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Home My WebLink AboutTract 30578, 30893Robert Stone & Associates, Inc. Engineering Geology • Soil Mechanics • Foundation Studies 19720 Ventura Boulevard - Woodland Hills, California 91364 213) 346-0565 - (213) 873-7382 E. L. Pearson and Associates 1551 West Redondo Beach Boulevard Gardena, California Subject: Monthly Report No. 3; Geologic Inspection and Soils Engineering Certification, Tract 30578, Diamond Bar, California Gentlemen: In compliance with the requirements of the County of Los Angeles, this report presents our opinions regarding the geologic and soils engineering conditions relative to the work performed on the subject tract between June 8, 1969 and July 7, 1969. CONCLUSIONS 1. The required geologic inspections were made during the above period. 2. Included in this report is additional data concerning stability of buttressed cuts in the vicinity of lots 16 and 17 on Steeplechase Lane, as requested earlier by the County Geologist. The data include a geologic map, cross-section and stability calculations. 3. Permanent cuts were started adjacent to lots 29, 30, and 44 along Rimfire Lane, and lots 22, 23 and 24 along Steeplechase Lane. These cuts are geologically favorable. E. L. Pearson & Associates July 8, 1969 68-301 MR-3 Page 2 4. Excavation and recompaction for the stabilization beneath lots 171-175 has been continued throughout this report period. In addition to the shear key design, total slide removal and recompaction in the vicinity of lots 25 and 26 has been undertaken. A separate report will be forthcoming and include detailed geologic and soils engineering investigations of this area. 5. Subdrains were installed under lots 104 and 105 adjacent to Kicking Horse Lane and lots 173-176 adjacent to Steeplechase Lane within the shear key. 6. .Filling has continued in the area of lots 171-175 and 24-26 along Steeplechase Lane. Filling has started on lots 104, 105 adjacent to Wagontrain Lane. These are not complete at this time. 7. Minor fill was placed adjacent to lot 75. This fill is not completed at this time. 8. The work done to date is in accordance with our recommenda- tions. Very truly yours, ROBERT STONE & ASSOCIATES, INC. Gene Hawkins, Engineering Geologist GH:RL:GG:rm Encl: And b} Geol. Map Cross-section Calculations Distribution: And b) 2 E. L. Pearson & Assoc. 3 County of Los Angeles Geology Section Robert Stone & Associates NO H N W N O w U 11 v J w IKW V 3 7 z ZH HN H HW 1 A Hw Ow W v u K WUaza ¢ N ow w 0 0VQ V a w zU ¢ Z Z yF F VI N 0M9 IOC fa. K 3 a 0 zwy3 N z 0. U/ l U; N HN O O z a a v H VH O 3 Lc) t3 Ov, h H h l III wA v I rn j S IA Y 2 6 j -9 YV7 aR, V; V a" VVV; nrW Ow 00 111?n tM 04V W&SISO Zeno in con 0101nM of into 173 V* ITS of ITOV 3AnT5 Q nw. 1 uncen aoy OrnavaMn nay lym was S"ns Avlowns sw 11upQ Wn M 1wevilow V? soub wCbVIACO TA10011" OV the VVI'Any 1510 low"WROVexagoOlm, zzymnant Ocoupred, wV "VaL =10 no" uAnt War? M20 Slarizzo wo"Y con to OVIVOWW' ryvWl plin? SAQ q AwKtes and Oww"nal Uri! and own ;rVAUVO so ful!... iorfn n in :* -101 1:7 of 140 20- ALOW to zrot W.; 30010an OT nh- Z11% Surfaus "Auralurd W Anyon;1IM qvoj'Q xv;O not unn K. Wl mr; Morynnsaw ;S00W4 too Zo 7orrnw. 1.V! Ohnn pnw•, w_ 11 SVAIOO to procaw: rp parmir Vint j.b vrnwv y of those Awt' n M qf pequany"A not! sm 11MOZA-Ma as, Von MOMON nw.: 41 ruvAlwa plans 4xv, 1""y noponvao, noll YCO horw p O"Istfor" Vn WO Atrsp "!wl WarAlwa ;a Mx-nnn 21-47;7, Moislor A US of mars :bonn o jounwim..; do: WOV IM7 YoNmi. ANA A. MMOVe CQUAT L AY.W Mon : . WIM"Inn QVIA Aminam UIST.91n, 010, VM] 9iM1 NICHOLAS R. JUSACK CxECUTw ON'ICER COUNTY OF LOS ANGELES PUBLIC \YtELFARE CO; IM,ISSION 1165 HALL OF RL'CORDS LOS ANGELES, CALIFORNIA 00012 TF.LEPRONE 028.OZII I.4ay 21, 1969 RECEIVED MAY 211969 B & S DIV. J. A. Thompson & Sons, Inc. 8330 Hindry Avenue Lou Angeles, California 90045 Attention: Md. Paul Ebensteiner Vice -President Gentlemen: COMMISGIONERS MRS. ANN n. T30YD PREAOENT MR. ELDRED MEYER, JR. 6ECRETRRY MRS. GOLDE OENSON MRS. GERTRUDE MAXWE11.L MRS. 13ETTY DE6S The Public Welfare Commission has approved your re- quest to'perf.'orm grading operations at Pathfinder and Diamond Bar Boulevard between the hours of 6:00 a.m. and 12 midnight- for a period of 30 days; normal hours only on the weekends. However, if the excavation of the key is completed prior to the expiration of 30 days,, the grading will return to the normal working hours. Sincerely yours, Nicholas R. Juback NR J: sw cc: Supervisor Bonelli Richard White, Chief Deputy William Jensen - Assistant Chief Deputy,,County Engineer San Dimas Building and Safety Division•. Sheriff's License Detail PWC File COUNTY OF LOS ANGELES DEF4,RTMENT OF COUNTY ENGINEER BUILDING AND SAFETY DIVISION PREPARE 10 TRTPLICATE) NOISE CONTROL ORDINANCE NO. 8594 Permission is hereby requested for performance of construction, repair or excavation work between the prohibited hours of/ 8:00 p.m. and 7:00 a.m. Location of Work l.e Work to be Performed Equipment to be used Date and Time of Work 56, T 41/<. Reason for Request: State basis for request under applicable category. a) Public interest b) Hardship, Injustice or Unreasonable delay d) Public defense Work performed prior to request - State reason why such work was necessary for the preservation of life or property: Requested by: Name Telephone l%b - e;'S Address Signatur Action of County Engineer: Q Permission granted Permiss on denied Date Copies to: Applicant Sheriff District Office Files 5-15-64:A COUNTY OF LOS ANGELES DEPARTMENT OF COUNTY ENGINEE BUILDING & SAFETY DIVISION 201 East Bonita Avenue San Dimas„ California 91773 Morning 9.128s, EDgewood 9-6281 John A. Lambie COUNTY E/NGG`INEEEER District :Engineer Dist. No. 41k Arthur G. SArnrinqendynt nf 00900 STAULIZITIM ON jyne 2, 1959 WS pry ?I,! jWq,y W SUU w of the Un d6lidn Mroon of y.'j 44P Q-Krqr PP AWN in -00410, NYC MUCH VS01n; MIMIS 54=15010d PhAint-', of n larkn shnir try not slown on the opproved gradinr.jnn. Sub- noguylb tv W07tinq of 01 PPY pycovinion, the nnCQnt'SQQ tc K norportod 1q, tip Qn-r koF Win to move Qzo Cho cRnivntion. Toi-sinvely, 1-001110- Ston US nuvCnOnL. A0 otop, orlyr wnn Wnn! 0 thn.lauter writunn Kny 22, 109 hy Wnn Por0o. MP looter idninod WonnMar novelopopno Aqppiny 01) nronved PQ fur0or y0h WN 000r 66 Ron 171-175 wbil-cartain sail 114 -nnizAn &ion 104 turn submitlyd Ind 117ro7ga. This anQ, as s hyhntrd iM win iwaitinj conrinHan K rn7iry Wo nyprninl to Vqw 21, MI. 7r. MrsDn Wn Wrtnirad, in My K Qn Lay 22 111z Rntrr whanka- to coild conkiv%e the 01101 operWon prior to fi-n! involvil of Wo ravisud raTarts ind yMns. No wAn Q- ilr, re nhit onlAW Dr. "inn Yon's nrrrDvv! of soils d7nn, to ripht W41or rv! v i A L! - nrUrs %-rdiny Q " gnalan: a imvivw 4c Yn can platat'! V 7-050— rnvnin- Aria A r17 rclukr- 7AMHOnn! 2ncor:=Ion p1dor nk M%] rn n of tho yrqdin- Mrondy !nWintad rq., At,- Pr, M.Ins r0milor! VAn opinion -A Fallcus: Wwirq I 70n.41 q-vpyorts Woo 5/27 Prd 5/21, ond wasinin,r, On- rn -M-nn- conlitin"s ire Mnd c0wr V%n UjinaM.-.' in tic -107- imonrLP, thr ov-r-nll f-clon of r4raw, Mar rVIS400- 40n W-Inn"Winar wSh M znynky Pool, nyp"Irs W Qinb A 400, ANG or KAY 0, - Pnort MW sq, winym a anny ryter or in, for t- 4rnrv- cit it h"A W of the inKarl sKin Mr M qppy ruporion "- y is rronuscf in thr ro"ASOK P100, The coycHun Mac- of ysf nacd in W" a-lenlition: nhouinn n 2,10 Whor is not 7nnridoryp to to rQVIP! %no n lywor v0i" closer LQ an neLunll rrHMA w0vurkh vn4r is vo:- rMaW. Mu Anylins the rrPvrn"- ont :n7 W! Yo 1MVP ind navn Won the rncovasiun as Wn alrandy horpqnr!(! it: IpW;r ptear hey, Weve", ac-norfing, to thn USCUSSIon, the qwnstidh of QnSty" of PersunnW, RAN tha-, ncivahip" " Wr Unny circunstnnipc in rrPrPpW by Stnte W,, ad rclyyntrd.oa ?x MILs7aard of InKsorial, Safky. Ph County MH jVWMWW:WQr Sc Mrond Sr Tcyclormeni-, Mopiny n7y well procand with excava- Wonfort" n upror go 111th nor 0SIUSHon and in 1ccbrdinze with rho 11drice- rounm0 tri them in the NAY 22 !Mtcr I Y .2 t 1?6-;.) Jun Pn7e 2 Thc ;K-Scurinz Gnolory Soctinn ntressos this auat be at their twn rist rundjan approvil GO the revised.grading rAns and thv, pnrA-vou TcRovic rapor; dated 5/27/0. it wDuli nrp:T Oat thu quolowic mp-does not show tic Wits, or V:ic- hounAries of the nnniant jandslido. , This is zn c&QxQA!z-Tt wouY Ad 811da'PlIna depicted in nq; of three tornsn-sMionn may only be the uppor slide nnnii Y7 dooper torirrn4 both A too hond of %he Aciant, slidn nnA no its.1uwar Voondnr7.nour the too. !K Smith, Senior Fujaworim Goolorist, toneurs in this opinion. TherWore, prior to npqravil A tna rrndinv plin, additionn! Wn will be naccasary to Mcw tho non-wAstonce of n denper slide p1nne thnn shown in rapci dinud 5/27M. P14,10 noto qabicgic Shal aGv Ari,'. hlr,- 3. cc: 7. L. MTSP-i Ro" w r5can nna Won. d to: Anst- hreW. 76G300-e-68 10 GEOLOGIC REVIEW SHEET Site Address Location Engineer Geologist Soils Engineer Review of: Grading Plan_ Building Plan_ Geologic Repo Soils Report_ Other Action: Remarks: Plan is approved Submit plans for recheck ENGINEERING GEOLOGY SECTION DEPARTMENT OF COUNTY ENGINEER SHEET 1 OF LOS ANGELES COUNTY DISTRIBUTION: Plan Check Dist. Engineer Grading Section File Geologist Soils Engineer Site Engineer DATE OF PLAN CHECK Plan is not approved (See Below) 1 Plan approved subject to conditions below In -grading inspection on June 17, 1969 noted that grading opera- tions in the vicinity of Lots 171-175 do not conform to the approved grading plan. As., of this date additi noa2!=fformation as requ'est-ed---, 1n fFie-`review sheet of 6-2-69 or a'revised grading plan has not been received or approved by the Engineering Geology Section. Based upon periodic field inspections during construction in the subject:area, specific comments on groundwater conditions and sub - drains will be required from the consultants prior to approval of the revised plan. RECF.:- JUN effiSoplSI Nio Checked by j/ 'ef: Approved by d ta Date 6-18-69 0 1 Mir'. Golemin Jenkins Arthur G. Keene Superintendent of Building LANMSUDE ST.AWLIZ TION O=Ju June 2, 1969 TATS 171-17 r;'le, ''" O tt^r, stillect of the landslide stibilinn- r_ o qn ,rirt. i!i: ;1 wnn :iisc:2ssed Present were Mr. Pearson OL d AnsoCirton, Dr. Stone and Jc. ry Gariln, _,oils s+ rn r; •.P .',';l.;i tf, Or problem rQsolvn6around unauthorized grnding of n l.nrrr; shear iov not shown on the approved grading plan. Sub- erm,rnnt to initiation of thn key excn,v?tion, the ancient slide to to nlprorted b; the sh^?r }`Qy hep'ap to move into the cxc;vntion. I.r,T-r,.nt,n1.-:. } ncl fillinn proceeded to stop the movement.stop ordar was is snod in the lettor writtr?n 1;!,:ny 21, 1969 by 'lle.nn irtin. ire lUter advised },inmand .:ar Developr..en't Company to proceed no further with the grading on lots 171-175 until certain soil and reolnr is into hod Loan submitted and approved. hiis data was snWitt:ari and rain awaiting- completion of review for approval on ?' i 100. ''Pr. Peirson then inq'.Il.red, in view of the Pay 22, 1;' lcttr,.,•rhr,t;}"..:" i'e could c:ontinge thn filling operation prior tofir- 1 nnnro'v'il. ^f th revised rcrorts and plans. Re was in- formed tVit rr'";•;:!_nn Di". "inn Yen's approval of soils data, he might r'rryrr ., r *r wY the the geologic review to }'C coNpleted v T- rsen•: rorninr Azne 1 nqy rR:!uirp addition?l informtFition! prior to POO nrrrnvil, end none of the vi.•odin," ilrnnrQ initiated may VIVO on to "nsonn. r r rrr&:i n71' . "r. V ..r W,s s4hinl'.trd Yin opinion as follows: i- rr, on tL,r rrrorts d.;W 5/07 and =/2", any? ?s,'_°'lmigi tick rn ^, q,,.ornp nnadj.`•.loWir^ found of}'nr thin indicated ed J_.i Q r j"ov, rrrartr, thn 1. v*r-ill fictor of Wet,;, after C on5t' r r`,ifon in lrr Nir,nr witl the roun'iy Code, nT'1 emirs to H7 thr, ro-WrN mini;ru of 1 °j1. lop .,r... or}. rl..rr., 5171 Andicites i sifety factor of 1..10 for the t amr ,_ rrY rut ;t t.;,,, Feld of t.',n „lrinrt sl.idn for the upper shvir 1qu is pr oposod In h- revised pl-n. ''hp tole slon vilar. of 3?' 0 ;nf ward ,thr colculntinns showing '1 1.10 factor is not considpred to herelichi^, and a lower value cloy?r to ,n 9ctunl r E1.!' 2't. mtrei l elm, is core nrobn This h l ,rr,h r r l;. 1i , irrplie the t,emrnr_ ry nut may wrl! h'r '1nstmbla and novc into the CY.cavation as Ws alrr-ndy Oppened at the lower shear key. J:owever, necording to the discussion, the cuestion of Safety of personnel doing the exe-vition, trader these circumstances in rreempted by State We and rr- lernted to ;:he jurisdiction of the State Poard of industrial Sof nt. The County bps no jurisdiction Linder these eircumstnnees. qT? Pigmord gar Development !'•f)iLr-n_y miy well proceed with excava- tion for the upper key in accordance with our discussion and in accordance with the "advice' presented to them in the ray 22 Letter. k i:r. Coleman Jen;:ins June 2, 196,9 Page 2 The Engineering Geology Section stresses this must be at their own risk pendinfi approval of the revised grading plans and the pertinent geologic report dated 5/27/6c). It would appear that the geologic map does not show the limits or the lateral boundaries of the ancient landslide. This is an emission. It would also appear that the slide plane depicted in any of three cross -sections may only be the upper slide until shown otherwise by deeper borings, both at the head of the ancient slide and at its lower boundary near the toe. Mr. Smith, Senior En'ineerinr Geologist, concurs in this opinion. Therefore, prior to approval of the grading; plan, additional data will be necessary to show the non-existence of a deeper slide plane than shown in report dated 5/27/(,9. Please note reolocic review sheet/attached. fe 7 cc: E. L. Pearson T.obert Otone and Assoc. d c : GEM CDs AGA 1-, n rrmen t: Arthur G. Keene Head Engineering Geologist iYilJ/eG is /967 G. DATE `- DONALD R. WARRENOO. JOB No. ENGINEERS 3BYLOSANGELES, CALIFORNIA 90012 SHEET t/51 i c'/GA pE l/ELO E/VT GO, s E BELAivSUBJECT-!! lREFERENCE__ f / / V ,4 Z- L G -z v Ztil ST M QTEo G ac, i o% of N5/ Ty j s j -r— EST / Q 6a L/tri/ Gp "EG oe 1vo. 9DwTFO 0:4-:jP7, /94k-:5 Bob Dickey Geotechnical Incorporated P.O. Box 694, San Juan Capistrano California 92675 714) 496-6102 May 15, 1978 Brimar Development 1312 Brooks Street Ontario, CA 91762 Attention: Mr. Gary Weber Subject: Geologic Review of Proposed Tentative Tract 34491 Formerly Lot 188 of Tract No. 30578), Alamo Heights Drive, "The Country", Diamond Bar, County of Los Angeles Gentlemen: This report summarizes the geologic work performed on Tentative Tract No. 34491. The site consists ofapproximately 7.5 acres of undeveloped 'hillside land located south of Steeplechase Lane and southeast of Alamo Heights Drive in the Diamond Bar area of Los Angeles County. The purpose of this investigation was to review the known geologic conditions of the site and to make conclusions relative to site development. A 30-scale grading plan by Loren Phillips and Associates, dated January 1978, was used as a basis for this review. Geologic notes i are plotted on a reduced version of this map, attached, with I' geologic sections also attached. SECTION Brimar Development - Alamo Heights Drive May 15, 1978 Page Two Geologic Findings Based on all geologic work.for Tentative Tract No. 3449.1, including various investigations for nearby areas, these conclusions are presented: 1. The site is considered to be grossly stable from a geologic viewpoint and suitable for residential development provided the findings of this and the soil engineering report are considered during site design and construction. 2. No evidence of active or potentially active faults was observed on the property. 3. No geologic hazards such as landslides, mass wastage, soil slumps, accelerated erosion or groundwater were observed on the property. 4.. No "Restricted Use Areas",as defined by the Los Angeles County Engineer, are considered necessary for this property and none have been designated. 5. Bedrock sandstone and interbedded siltstone underlie the surface at fairly shallow depth. These materials can provide adequate, support for structures and for structural fills. Bedding planes were found to dip easterly, into the natural hillside slopes, a stable configuration. 6. Surficial materials consist of slopewash and soil overlying the bedrock. These deposits are soft and porous, subject to settlement under imposed loads. Foundation excavation and sidehill fill keyways should penetrate the surficial deposits to avoid detrimental settlement. r Brimar Development - Alamo Heights Drive May 15, 1978 Page Three 7. The subject grading plan is considered to be geologically satisfactory and is therefore approved. Specific notes should be added as follows: a. Geologic inspections should be conducted during site grading, with geologic notes plotted on an approved grading plan. b. All sidehill fill keyways, cut slopes, and foundation excavations should be geologically inspected and approved prior to removal of grading equipment from the site. c. A Final As -Graded Geologic Map of Rough Grading should be submitted to the County Engineer at the completion of rough grading to provide a record of geologic conditions encountered. Thank you for this opportunity to be of continued service on this project. This study has been conducted in accordance with generally accepted practice in the field of engineering geology. No further warranty is offered or implied. Please call (714) 496-6102 if there are any questions. Respectfully submitted, BOB DICKEY GEOTECHNICAL INCORPORATED By R. H. DICKEY, E7 914, R.C.E. 9 5 RHD:mb Attachments: Appendix - Geology Geologic Map Geologic Cross Sections Distribution: Addressee (4 copies) Brimar Development - Alamo Heights Drive May 15, 1978 Page Four APPENDIX - GEOLOGY The topography on the site consists of gently to moderately sloping hillsides with east -west trending ridges and west draining canyons. Elevations on the property range from approximately 925 feet near the southwesterly corner to about 1045 feet near the northeasterly property boundary. The site is mantled with sparse to locally moderately dense wild grasses, oak trees, and chaparral -type brush. Drainage is mainly by sheet flow into west draining canyons or to the west within the northerly portion of the site. No seeps, springs, or unusually moist areas were observed on the property. No structures or significant fills were observed on the site. Engineering Geology The property is underlain by marine sedimentary rocks of the Puente Formation of upper Miocene age. These bedrocks consist of light brown to medium brown moderately hard to hard, well - cemented, medium to coarse -grained sandstone with interbedded, laminated, gray green, clayey siltstone. Slopewash deposits, ranging from 1 to 3 feet in thickness, mantle the majority of the property. The bedrocks in the proposed development dip downward to the east and north between 8 and 29 degrees. The geologic structure on the site is homoclinal. Variations and some reversals of this general pattern may be present as a result of minor folding, soft -sediment deformation, and minor faulting. Brimar Development - Alamo Heights Drive May 15, 1978 Page Five No faults were observed on the property. The closest known active or potentially active fault to the site is the Whittier Fault, located within 3 miles to the south. No landslides or areas of potential instability were observed on the site. Proposed Grading The proposed grading will create 11 level pads for residential construction with minimal grading required. The natural slopes above the proposed pads have bedrock bedding planes dipping into the slopes and should be stable as planned. In -grading mapping will be required to confirm this condition. 9 . 1 32165 Via Carlos, ,;.in .1•t rt Capi:;tr; to January 27, 1977 Duco Engineering 1170 Centre Drive, alnut, California California 92G75 714) 493-5207 '(213) 964-3440 1-/dAl Suite F V Q Attention: 'Mr. 11arvey Dufrenne C,61H Subject: Geologic Review of Proposed Single -Family Residence to be constructed on Lot 176 Tract 1,0. 30578, Steeplechase Road, The Country, Diamond Bar, County of Loa Angeles Gentlemen; This geologic review has been completed at your request to provide input for preparation of the development plans. This study has included a site reconnaissance, a revi(!w of previous geologic and soil reports by Robert Stone L Associates, review of "Grading Plan" by Travis L. Manning, R.C.E., dated 1-12-77, and preparation of this report. Geologic Conclusions and Reconmendations The proposed development is considered to be geologically feasible, provided the recommendations of this report are considered during development. 1) Tile proposed pad will be cut into bedrock lying beneath and dipping toward a landslide on the northerly slope. The "Restricted Use Area" designated for this and adjoining lots is on the landslide. Ledrock sandstone and siltstone beneath tLe slide dips north and northeast at 15 to 24o in existing e:po;ures rapped by Stone. I` The proposed grading will provide a lot pad supported on bedrock dipping beneath the slide to the north, a stable configuration. Tile proposed cutslope should expose into and along -slope dipping bedroc_lc, likewise a stable configuration. The cut pad and slope s;;ould be geologically napped during grading, with footing cavations also geologically inspected. Excavations in the rear corner of the residence nay require deepening, as determined dur- ing inspections. 2) The Dianond Bar area is considered to be about average or slightly below average for seismic shaking potential. Earthquakes hosted on offsite active faults can be enpected to cause ground shaking at the project site. This shakin— is anticipated to be comparable to normal Zone III seismic loading for building design. Actual ground rupture is considered unlikely. Secondary seisnic effects, such as lurching and liquefaction, are also considered to NGIIv! EERiNG ; vLest91. SECTION FEB 7 1978 b , un7.ibcrly. Thant; you for this opportunity to be study has been conducted in accordance practice in the Geotechnical field. ]io offe.red or implied. Please call (714) questions. Respectfully, Robert H. Dickey, G. G. 7 4 Attachments: References Distribytion: Original to Duco of service. Phis geologic with generally accepted further warranty is 493-5207 if there are any oniuj - I I.:,:iiase I nuary 27, 1977 p.1 ;c th rye 1. REFE1;1:1,CES 1:ovember 5, 1977 "Final As -graded Geologic Report, Rough Grading Completed, Tract 30578, Diamond Tear, California," by Robert Stone G Associates November 5, 1977 "Soil Engineering Report on Compaction Testing, Tract 3D578, Lots 1 through 183 and Tract 30289, Lots 6 through 8, Diamond liar, County of Los Angeles California," By Robert Stone 6 Associates December 15, 1976 Geologic Review Sheet: Lot 176, Tract 3o. 30578, Diamond liar, by Engineering Geology Section Engineering Geology; Soil and Rock Engineering, Geohydrology CI;®TECHNICAL CONSULTANTS, INC GRADING CGp Coast Construction Company 2082 Business Center Drive Suite 200 Irvine, California 92664 Attention: Mr. Mike Rowe Burbank, California Santa Ana, California Ventura, California May 8, 1973 MAY. 151016 Subject: Geotechnical Review and Inspection of Lot 175, Tract 30578, Steeplechase Lane, Diamond Bar, County of Los Angeles, California Gentlemen: Our Job S3088 Per your request, we have made an engineering and geologic evaluation of the subject lot based upon a cursory field inspection and review of available geologic and engineer- ing reports. study: The following references were reviewed during this 1) "Grading Plans, Tract 30578, Diamond Bar, County of Los Angeles, California", dated January 13, 1969, for E.L. Pearson and Associates, Job No. 68-301, by Robert Stone and Associates, Inc. This report presents the opinions regarding geologic and soils engineering factors affecting the grading plans for Tract 30578. No maps or sections associated with this report were available for our review. Under the heading "Landslide Northern Area", this report notes that three slides occurred in the vicinity of Lots 169 through 178. Topographic infor- 2001 East 4th Street, Suite 102, Santa Ana, California 92705 Phone (714) 547-5413 Our Job S3088 Coast Construction Company Page 2 I iI}LrL1 r mation on two of the slides suggesting that they are relatively recent, however, they have been inactive for a long time. The third and largest is apparently so ancient that soil creep and erosion have obliterated topographic features that characterize younger slides. Subsurface exploration, however, indicated that the head and western edge of this slide are marked by deep soil and firm debris composed of bedrock. At boring B-15, Lot 24, disrupted bedrock terminates along the shear surface at a depth of 20 feet. This is apparently the base of the slide. In bor- ing B-11, Steeplechase Lane, the slide base was not identified due to the presence of faulting and folding interpreting the tectonic origin. In borings B-13 and B-14, Lot 175, the base of both the younger and older slides is interpreted to be 40-1/2 feet and 37 feet, respectively. This section also discusses at length the reason for choosing a shallower slide surface base at 30 feet instead of a deeper 48 foot depth, noted in Moore and Taber's boring B-29. As stated, Robert Stone and Associates, Inc. interpret that 48 foot shear as being of tectonic origin and probably a bedding plane shear. Under the heading "Conclusions and Recommendations" it is noted that Lots 170 through 176 have restricted.use areas beyond the 100 foot line buildable area extending downslope from the outer edge of the road. This 100 foot wide area will be stabilized by removal and recompaction of slide material. Sta- bility calculations are attached to this report. 2) "Final -As -Graded Geologic Report, Rough' Grading Completed, Tract 30578, Diamond Bar, California", dated November 5, 19709 for E:L. Pearson and Associates, Job'No. 1-68-301-09, by Robert Stone and Assoc- iates, Inc. This report states that from a geologic standpoint, the rough grading is approved and that there is a safe building area on each lot. The majority of Lot 175 along the north side has been established as a restricted use area due to a landslide. As shown on sheet 7-A of the grading plans, bedding within the Puente formation is principally dipping in a north northeasterly direction at inclinations of 14.to 30 degrees from the horizontal. With regard to the landslide, the report states that.shear keys have been constructed on Lots 170-176. Our Job 53088 Coast Construction Company Page 3 3) "Soil Engineering Report on Compaction Testing, Tract 30578,.Lots 1 through 188, and Tract 30289, Lots 6 through 8, Diamond Bar, County of Los Angeles, California", dated November 5, 1970, for E.L. Pearson and Associates, Job No. 1-68-301-10, by Robert Stone and Associates, Inc. FiN 1, u ! This report again discusses the presence of a shear key and restricted use areas across Lot 175. According to this report, vegetation, brush, trees, debris and other deleterious materials were removed prior to the placement bf compacted fill. The canyon bottoms were cleaned of loose soils and/or alluvium as determined in the field during excavation by the supervising soils engineer. As shown in Table II "Analysis of Building Areas", the level building area at the south end of Lot 175 is composed of siltstone fill materials having a percent swell of 4.9 under a 60 pound per square foot load. GEOTECHNICAL CONCLUSIONS AND RECOMMENDATIONS We understand that a one- and/or two story sewered residential structure will be constructed on the south side of Lot 175. As shown on grading plan (dated March 26, 1973) no significant grading will be performed within the proposed build- ing area. A minor amount of grading will be conducted in the area now shown as "Restricted Use Area". This is primarily for drainage control and should.not effect the stability of this lot. The easement area for Los Angeles County slope pur- poses noted on the north of the lot as shown on the March 26, 1973 grading plan by E.L. Pearson and Associates is in a,restricted use area. No cuts should be made in the restricted use area or the future street area, since the stability calculations provided by Robert Stone and Associates, Inc. did not take into account cut at the -toe of the landslide. Geotechnical Consultants, Inc. has not considered any future street grading in its analysis of the data. The existing near level building area at the south end of the lot is presently covered with a heavy concentration of low growing vegetation. This vegetation should be removed from the pad I i 11 Our Job S3088 Coast Construction Company Page 4 surface prior to the start of grading. The upper six to eight inches of the previously graded near level portion of Lot 175 should be scarified, watered as required and recompacted to a minimum of 90 percent relative compaction. Basically, the general notes on the construction plan remain applicable to the proposed grading with the follow- ing exceptions: 1) The specific provision for a minimum' number of density tests to be taken by the sand cone method, will not be re- quired. 2) All fills should be compacted to a mini- mum 90 percent of the maximum density as determined by ASTM soils compaction test D1557-70T, modified to three layers. 3) The fill base should be approved by an engineering geologist and continuous grading control maintained on the fill placement:' Based upon our engineering review and site inspection, the following foundation recommendations are anticipated at this time: 1) Piers and continuous foundations can be designed for a bearing pressure of up to 1500 pounds per square foot. The footing width, however, should not be less than 12 inches. 2) Pier foundations should be 16 to 18 inches in diameter and should extend a minimum of 24 inches into firm compacted fill. 3) Continuous wall footings should extend a minimum of 18 inches below lowest adjacent finished grade into firm compacted fill, Our Job 53088 Coast Construction Company Page 5 4) Wall footings should be reinforced with minimum one No. 4 bar, top and bottom, 5) Concrete slabs on grade should have a minimum thickness of 3-5/8 inches with 6 x 6-No.6/No.6 wire mesh reinforcement. The base of the concrete slab should be protected with an approved moisture barrier such as Visqueen. 6) The expansion characteristics of the foundation materials should be verified at the completion of grading and the foundation recommendations revised, if necessary. 7) A footing inspection should be made by a qualified soils engineer and engineer- ing -geologist prior to the placement of steel. Any significant changes in the grading plans, dated March 26, 1973 should be reviewed by Geotechnical Consultants, Inc. Very truly yours, GEOTTECHNICAL CONSULTANTS, INC. Robert I. Misen, Engineering Geologist 658 CGG?uzi A. Siddiqui;. Civil Engineer 19915 RTM:SAS:gmm 6) copies submitted cc: E.L. Pearson and Associates Att: Mr, Gary Brewton Engineering Geology, Soil and Rock Engineering, Geohydrology CEOTECHNICAL CONSULTANTS, INC Burbank, California Santa Ana, California MAY 151973 Ventura, California MAY 151915 Ma 8 1973 ENGINEERING GEOyLOGYY SECTION Coast Construction Company 2082 Business Center Drive Suite 200 Irvine, California 92664 Attention: Mr. Mike Rowe Our Job S3088 Subject: Geotechnical Review and Inspection of Lot 175, Tract 30578, Steeplechase Lane, Diamond Bar, County of Los Angeles, California Gentlemen: Per your request, we have made an engineering and geologic evaluation of the subject lot based upon a cursory field inspection and review of available geologic and engineer- ing reports. study: The following references were reviewed during this 1) "Grading Plans, Tract 30578, Diamond Bar, County of Los Angeles, California", dated January 13, 1969, for E.L. Pearson and Associates, Job No. 68-301, by Robert Stone and Associates, Inc. This report presents the opinions.regarding geologic and soils engineering factors affecting the grading plans for Tract 30578. No maps or sections associated with this report were available for our review. Under the heading "Landslide Northern Area", this report notes that three slides occurred in the vicinity of Lots 169 through 178. Topographic infor- . 2001 East 4th Street, Suite 102, Santa Ana, California 92705 Phone (714) 547-5413 Our Job 53088 Coast Construction Company Page mation on two of the slides suggesting that they are relatively recent, however, they have been inactive for a long time. The third and largest is apparently so ancient that soil creep and erosion have obliterated topographic features that characterize - younger slides. Subsurface exploration, however, indicated that the head and western edge of this slide are marked by deep soil and firm debris composed of bedrock. At boring B-15, Lot 24, disrupted bedrock terminates along the shear surface at a depth of 20 feet. This is apparently the base of the slide. In bor- ing B-11, Steeplechase Lane, the slide base was not identified due to the presence of faulting and folding interppreting the tectonic origin. In borings B-13 and B-14, Lot 175, the base of both the younger and older slides is interpreted to be 40-1/2 feet and 37 feet, respectively. This section also discusses at length the reason for.choosing a shallower slide surface base at 30 feet instead of a deeper 48 foot depth, noted in Moore and Taber's boring B-29. As stated, Robert Stone and Associates, Inc. interpret that 48 foot shear as being of tectonic origin and probably a bedding plane shear. Under the heading "Conclusions and Recommendations" it is noted that Lots 170 through 176 have restricteduse areas beyond the 100 foot line buildable area extending downslope from the outer edge of the road. This 100 foot wide area will be stabilized by removal and recompaction of slide material. Sta- bility calculations are attached to this report. 2) " Final As -Graded Geologic Report, Rough Grading Completed, Tract 30578, Diamond Bar, California", dated November 5, 1970, for E.L. Pearson and Associates, Job No. 1- 68-301-09, by Robert Stone and Assoc- iates, Inc. This report states that from a geologic standpoint, the rough grading is approved and that there is a safe building area on each lot. The majority of Lot 175 along the north side has been 'established as a restricted use area due to a landslide. As shown on sheet 7-A of the grading plans, bedding within the Puente formation is principally dipping in a north northeasterly direction at inclinations of 14 to 30 degrees from the horizontal. With regard to the landslide, the report states that shear keys have been constructed on Lots 170-176. Our Job S3088 Coast Construction Company Page 3 3) "Soil Engineering Report on Compaction Testing, Tract 30578, Lots 1 through 188, and Tract 30289, Lots 6 through 8, Diamond Bar, County of Los Angeles, California", dated November 5, 1970, for E.L. Pearson and Associates, Job No. 1-68-301-10, by Robert Stone. and Associates, Inc. This report again discusses the'presence of a shear key and restricted use areas across Lot 175. According to this report, vegetation, brush, trees, debris and other deleterious materials were removed prior to the placement of compacted fill. The canyon bottoms were cleaned of loose soils and/or alluvium as determined in the field during excavation by the supervising soils engineer. As shown in Table II "Analysis of Building Areas", the level building area at the south end of Lot 175 is composed of siltstone fill materials having a percent swell of 4.9 under. a 60 pound per square foot load. GEOTECHNICAL CONCLUSIONS AND RECOMMENDATIONS We understand that a one- and/or two story sewered residential structure will be constructed on the south side of Lot 175. As shown on.grading plan (dated March 26, 1973) no significant grading will be performed within the proposed build= Ing area. A minor amount of grading will be conducted in the area now shown as "Restricted Use Area". This is primarily for rrainage control and should not effect the stability of this lot. The easement area for Los Angeles County slope pur- poses noted on the north of the lot as shown on the March 26, 1973 grading plan by E.L. Pearson and Associates is in a.restricted use area. No cuts should be made in the restricted use area or the future street area, since the stability calculations provided by Robert Stone and -Associates, Inc. did not take into account cut at the toe of the landslide. Geotechnical Consultants, Inc. has not considered any future street grading in its analysis of the data. The existing near level building area at the south end of the lot is presently covered with a heavy concentration of low growing vegetation. This vegetation should be removed from the pad Our Job S3088 Coast Construction. Company Page 4 surface prior to the start of grading. The upper six to eight inches of the previously graded near level portion of Lot 175 should be scarified, watered as required and recompacted to a minimum of 90 percent relative compaction. Basically, the general notes on the construction plan remain applicable to the proposed grading with the follow- ing exceptions: 1.) The specific provision for a minimum number of density tests to be taken by. the sand cone method, will not be re- quired. 2) All fills should be compacted to a mini- mum 90 percent of the maximum density as' determined by ASTM soils compaction test D1557-70T, modified to three layers. 3) The fill base should be approved by an engineering geologist and continuous grading control maintained on the fill placement. Based upon our engineering review and site inspection, the following foundation recommendations are anticipated at this time: 1) Piers and continuous foundations can be designed for a bearing pressure of up to 1500 pounds per square foot. The footing width, however, should not be less than 12 inches. 2) Pier foundations should be 16 to 18 inches in diameter and should extend a minimum of 24 inches into firm compacted fill. 3) Continuous wall footings should extend a minimum of 18 inches below lowest adjacent finished grade into firm compacted fill. Our Job 53088 Coast Construction Company 4) Wall footings should be reinforced with minimum one No. 4 bar, top and bottom. 5) Concrete slabs on grade should have a minimum thickness of 3-5/8 inches with 6 x 6-No.6/io.6 wire mesh reinforcement. The base of the concrete slab should be protected with an approved moisture barrier such as Visqueen. 6) The expansion characteristics of the foundation materials should be verified at the completion of grading and the foundation recommendations revised, if necessary. 7) A footing inspection should be made by a qualified soils engineer and engineer- ing geologist prior to the placement of. steel. Any significant changes in the grading plans, dated March 26, 1973 should be reviewed by Geotechnicai Consultants, Inc. Very truly yours, GEOTECHNICAL CONSULTANTS, INC. Im Wm Robert T. Misen, Engineering Geologist 658 A. • Siddiqui;"_--- Civil Engineer 19915 RIM: SAS: gmm 6) copies submitted cc: E.L. Pearson and Associates Att: Mr. Gary Brewton 211.1 south Mn,4 1`e .ice Siii1ona ..:`! California jantlemm MAY 2 6 i969 13ci3-r:s'c;"I0 11716 Tr'. _ LM MET= t .r.T, ITY will 171 'ci: r na .. •.,vr i`rr rf .`. r.. :.'.... :.. ri SAN DUO AS t. ':al': i':ctt}!t ,S`o;`! .. r': :a' .:a•:. t;h'1= M .1af.dsAI M 1,•1 M1 dt i.•.Mdii vors to tho •J"".'.:~intr of lots 271 to 275 of Tract r7 is not Bing .::'' rpli' heJ in .....:'FCfroancu with ''.'.he ts•rsa•i.4i'.:il Y}„.'"" E"C•".ynd 1$'.stya. A Mar 1: r;y -r"C.:tVi,tin i haw -illen .'.adn Pll.:vt rM:l::lco 47.7'an AU"w:from Yi-:?:•] of _aC c=cvvLk1cn Micated an the n.„ rQv:.. rill"•... t'p210eing :'.•.'2`•.. :t t` VEll;«"3:s:, ..::i`:',iy:140 1.".:rt':':.'.ent occurred., We mua is ?"at! i y you that "?fr}re this al a:`ri _Cs work • Yy :'. nil :i . i :'Sj'•rY::..A s^1avised plans must .j i..Y:.i.Yi -and i]:::•:iir'•r.4nn! s%.'t,.i. and t+.o J.agli:Vi, data •rovlu^:.r as WHO*: t.• 7:19"f: €! ,t,' the 710, 0 chn now w2jda no i,nat toc, J.tYi•as.41as ... the =Mu pa,j_f n`. can ;"e r! I:•'w(:twv',nt')v'.(i .rlJ. ... (' P .l i1n• y sp+drro .Paso ff4`:.logiC 1:apa and en '". Coll test inforKMon .. Itranesh i.t m f v: : tT.7'i. at IM wily 000000, 3vi ven vo rrv.. a n•n !'ti....v a...t.. r. .:+`. <t f.T 'r nn x .. ra •1. .PSU.S .. .e. .. ... .. .. . . L;.. i: r. . v- t:... wnt. Mtn i:n i. :$] l t requested 510and toologic Ma his hver i; :iafi..r °:: Ci are: otal'-1 •,' Cali !-:av'.. q J"Si;'.' :ill^. an ill'. iz 0,e0V r:oAnz tall c' undarzimd at tollphnno •;,2.. •A t`%ers :3'.'•..fi. c7 l?n Ott ::Cr. Mon A. saybto PRO! J( Siied Cam' ?ciC: c^L' 0000 4 1n1:300.:.0= ivar:fi n do : GEOLOGY, GRADING, DIST. ii10 , t'rE i, F1LL' 61 V 1. NICHOLAS R. JUDACK EXECUTIVE 0F1'ICLR COUNTY OF LOS ANGELES PUBLIC \1%E..rA)tE C01MM1SS10Y IIGG HALL OF RECORDS LGS ANGELES, CALIFORNIA 90012 TELEI'S011E G28-9211 May 21, 1959 RECEIVED MAY 211969 B & S DIV. COMMISSIONCRS MRS. ANN . DOYD PREmOENT MR. ELDRED MEYER•JR. SECRETARY MRS, GOLDS DENSON MRS. GERTRUDE MAXWE..L MRS. DETTY DEDS J. A. Thompson & Sons, Inc. 83S0 Hindry Avenue Los'Angeles, California 90045 , Attention: Mr. Paul Ebensteiner Vice -President Genolemen: The Public Welfare Commission has approved.your re- quest to* perform grading operations at Pathfinder and Diamond Bar Boulevard between the hours of 6:00 a.m, and 12 midnight for a period of 30 days; normal hours only on the weekends. However, if the excavation of the key is completed prior to the expiration of 30 On, the grading will return to the normal working hours. Sincerely yours, it •_ Nicholas R. Juback NRJ: s;a cc: Supervisor Bonelli Richard White, Chief Deputy William Jensen - Assistant Chief Deputy, 1 County Engineer San Dimas Building and Safety Division;, Sheriff's License Detail PWC File ME COUNTY OF LOS ANGELES DEPARTMENT OF COUNTY ENGINEER BUILDING AND SAFETY DIVISION PREPARE IN TRTPITEATE) NOISE CONTROL ORDINANCE NO. 8594 Permission is hereby requested for performance of construction, repair or excavation work between the prohibited/ hours of/ 8:0,r0 p.m. and 7:00 a.m. Location of Work Imo;, 1W/Ilyj Z,4,C Work to be Performed E Equipment to be usedFi Date and Time of Work 30 T Go 24Z!r ' Reason for Request: State basis for request under applicable category, a) Public interest b) Hardship, Injustice or Unreasonable delay 90 d) Public defense _ Work performed prior to request - State reason why such work was necessary for the preservation of life or property: Requested by: Name ,:T„ %>. tir • Telephone Z/G Address Signatur Action of County Engineer: Q Permission granted Permission denied Date / Copies to: Applicant Sheriff District Office Files 5-15-64:ak COUNTY OF LOS ANGELES DEPARTMENT OF COUNTY ENGINEER BUILDING & SAFETY DIVISION 201 East Bonita Avenue San Dimas, California 91773 Morning 9.1286, EDgewood 9.6281 John A. Lambie COUNTY ENGIN/EEEERj Z", District, —Engineer Dist. No. l . GEOTECNNICAL CONSULTANTS, INC. Burbank • Santa Ana • Ventura, California Bergum Construction Company 1023 East Chapman Avenue Fullerton, California 92634 Attention: Mr. Al Bergum Subject: Results of Field Density Tests in Fill and Foundation Design Recommendations, Lot 180, Tract 30578, Diamond Bar, County -of Los Angeles, California r Gentlemen: March 3, 1977 C-S77040 This letter presents the results of our field density tests performed in the fill placed on the above'lot in Diamond Bar, California. Included are conclusions and foundations design recommendations. The estimated locations of the field density tests are shown on Plate 1 - Geotechnical Map. The results of compaction tests on re- presentative samples of the soils used in the fills and the method of com- paction are presented on Plate 2 - Summary of Compaction Test Data. At the time of our testing of fill (March 2, 1977), excavation of the footing trenches for the structure was in progress. Results of field density tests performed, including those in the bottom of the trench, are presented on Plate 3 - Results of Field Density Tests. The tests were performed by the drive ring method. 2001 East 4th Street, Suite 102, Santa Ana, California 92705• Phone(714) 547-5413 C-S77040 CONCLUSIONS AND RECOMMENDATIONS GENERAL Test results (Plate 3) show relative compaction of the fill varies from 90 to 96 percent. This compaction should be satisfactory for support of the light wood frame residential structure as proposed, pro- vided the recommendations included in this report are followed in design and construction. Our inspection of the site indicates that some clearing of the weeds has been performed and a bridle path has been dozed in the restric- ted -use area designated on the lot. In our opinion, this is minor and not significant for the stability of the lot. DRAINAGE Drainage should be directed and maintained away from the foundations and slopes toward the street or approved drainage devices. FOUNDATION DESIGN Based on our inspection, classification and review of previous reports, the upper foundation soils are moderately to highly expansive. Considering this and the transition cut -fill lot, the following foundation recommendations should be satisfactory for construction: 1. Continuous foundations and piers can be designed for a bearing pressure of up to 1500 pounds per square foot. However, the footing width should not be less than 12 inches. 2. Continuous exterior and interior wall footings, tied to each other, should extend a minimum of 18 inches into firm compacted fill or Puente Formation materials. Piers should extend a minimum of 24 inches into firm compacted fill or Puente Formation materials. 3. Wall footings should be reinforced with a minimum of two No. 4 bars at the top and two at the bottom. 6 C-S77040 We3 4. The concrete slabs subgrade should be presoaked to a depth of at least 18 inches below the bottom of the slab to a mini- mum 90 percent saturation. This should be verified by a soils engineer. 5. Concrete slabs on grade should have a minimum thickness of 3-5/8 inches with 6 X 6-No.6/No.6 wire mesh reinforce- ment properly centered in the 'slab. The base of concrete slabs beneath the living areas should be protected with an approved moisture barrier such as Visqueen. 6. All footing excavations should be inspected and approved by Geotechnical Consultants, Inc. prior to placing building materials. An approved foundation plan should be provided to this office to facilitate this inspection. If you should have any questions regarding this, please do not hesitate to call us. Very truly yours, GEOTECHNICAL CONSULTANTS, INC. Q2W `91.n Robert T. Misen Engineering Geologist 658 S. A. Siddiqui J Civil Engineer 19915 RTM:SAS:cb 4 copies submitted Attachments: Plate 1 - Geotechnical Map Plate 2 - Summary of Compaction Test Data Plate 3 - Results of Field Density Tests C-S77040 SUMMARY r. Plate 2 Gf5 OF COMPACTION TEST DATA COMPACTION CURVE NO. S 0 1 L T Y P E OPTIMUM MOISTURE CONTENT IN PERCENT OF DRY WEIGHT MAXIMUM DRY DENSITY IN POUNDS PER CUBIC FOOT 1 SANDY CLAY (CL) with shale, 16 107 dark brown 2 SANDY SILT (NIL) with clay, 18 113 red -brown NOTE; Tests taken from Robert Stone and Associates report dated November 51 1970 (Job 1-68-301-10) METHOD OF COMPACTION ASTM STANDARD TEST METHOD D-1557-70 EQUIVALENT TO A.A.S.H.O. SOIL COMPACTION T180 TI80-57(1/30CUBIC FOOT MOLD,IOPOUND HAMMER FALLING IB INCHES,25 BLOWS PER LAYER), MODIFIED TO THREE LAYERS. C-S77040 Plate 3 RESULTS OF FIELD DENSITY TESTS TEST NO. TEST LOCATION STATION DEPBELOWTH SURFACE SURFACE ELEV. b COMPACTION CURVE MAXIMUM DRY DENSITY LBS./CU.FT. FIELD MOISTURE TEST DRY DENSITY LBS./CUFT. RELATIVE COMPACTION RETEST NO. 1 Footing 864 1 107 18.4 102 96 2 Footing 864 1 107 22.7 98 92 3 Yard Fill 864' 1 107 14.2 102 96 4 Slab Area 865' 1 107 20.6 99 93 5 Slab Area 865' 2 113 17.3 102 90 6 Footing 864' 2 113 14.3 97 86c b. Elevations are approximate. c. Test taken in original ground. Robert Stone & Associates, Inc. Engineering Geology - Soil Mechanics • Foundation Studies 19720 Ventura Boulevard — Woodland Hills, California 91364 213) 346-0565 — (213) 873-7382 May 28, 1969 tl L'- 8 In69 68-3015 E. L. Pearson and Associates ENGINEc:P NG G E 0 L O G r 1551 W. Redondo Beach Boulevard SECTION Gardena, California Subject: Additional Soils Engineering Information, Tract 30578, Lots 170-176, Diamond Bar, Los Angeles County. Gentlemen: This report presents our further opinions regarding additional soils engineering information for the subject reference. It supplements our eralier report dated May 27, 1969. FIELD CONSTRUCTION OF UPPER SHEAR KEY We have analyzed the translatory stability of the slide mass uphill from the upper shear key at.the time the construction cut will be made. We have analyzed this cut for two sets of shear strength parameters: a) Parameters obtained from-mu1-ticycle shear tests on slide plane materialI x-, 0 C = 320 psf1i) b) Parameters obtained by calculations which considered the geometry.of the slide ss-before—the earlier reported failure E Our calculations indicate adequate Factors of Safety will be present for the construction case. In the area of Section 1-l', we recommend an additional --five feet of material be removed in the area shown on the attached cross section; this is necess- ary to remove additional driving force, and provide an adequate Factor of Safety. E. L. Pearson and Associates 68-301S May 28, 1969 Page 2 Selection of Strength Parameters We have selected the above shear strength parameters based on the condition that the excavation will be open only for the minimum time necessary to perform the grading. In this short period, we do not believe progressive failure will develop due to loss of cohesive strength along the slide plane. Installation of the Shear Key To minimize the possibility of failure during grading, we recom- mend the shear key be installed in three sections (or slots). The middle section should be installed first, so as to receive lateral support from the two outer areas of the mass. We will provide inspection of the grading. We do not expect movement during this excavation, however if it occurs, it will be slow enough that equipment and workmen can be withdrawn. MINIMUM DEPTH OF FILL To. provide a firm mat of compacted fill for foundation, a minimum of 10 feet of compacted fill should be placed beneath all build- able areas. ADDITIONAL SOIL DATA Our laboratory determination of unit weight and moisture on pieces of the slide plane material gavethe following result I Unit Dry Weight 102 lb/cu f.t.. Moisture Content 27.0 percent. GG/ jl Distribution 2 E. L. Pearson 2 County of Los Angeles, Engineering Geology Very truly yours, ROBERT STONE SSOCIATlS INC. By Gerald Gorian, RCE 14698 Robert Stone & Associates E. L. Pearson & Associates May 28, 1969 68-3015 Page ANALYSES OF TRANSLATORY STABILITY DURING CONSTRUCTION FOR THE UPPER SHEAR KEY IN SECTIONS 1-l', 2-2' and 3-3' ON DIAMOND BAR Section 1-1' Angle Normal Slide Force Area Weight Plane Wt SirvC W Cosh. Segment Sq In. kips 0L SinoL CosaL kips kips A 0.62 124 20 342 94 42 117 B 0.40 80 16 276 961 22 77 Total 64 184 Length of the slide plane = 140 ft Computations for Factor of Safety F A) For C _ps•€ an QJ =50 tan =0.1 49 i Resistance = 184 x .149 + 140 x 0.32 27 + 45 + 72 F = 72 64 = 1.13 3) For C = 290 psf and = 90 tan (d = ..158 Resistance = 184 x .158 + 140 x .290 29 + 41 = 70 / Ax V F G Robert Stone & Associates E. L. Pearson & Associates May 28, 1969 Section 2-2' Angle Slide Area Weight Plane Segment Sq In. kips of A 0.92 184 17 B 0.85 170 14 68-301S Page Normal D.F. Force Wt SinA- W Cosa(. Sin aL Cos 4 kips kips 292 .956 54 176 242 .970 41 165 Total 95 341 Length of Slide Plane = 198 ft Computations for Factor of Safety F A) For C = 32 and 0 tan = 0.149 Resistance = 341 x .149 + 0.32 x 198 51 + 63 = 114 F =, 1- = 1.20 B) For C = 290 psf and = 90 tan _ .158 Resistance = 341 x .158 + .290 x 198 54 + 57 = 110 F 11095 Robert Stone & Associates E. L. Pearson & Associates May 28, 1969 Section 3-3' Angle Slide Area Weight Plane Segment Sq In. kips c4- Sind - A 0.29 58 20.5 0.350 Length of the Slide Plane = 80 ft 68-301S Page Normal D.F. Force Wt Sinck W Cosh Cos kips kips 0.937 20 54 Computations for Factor of Safety F A) For C = 320 psf, 0 = 8.50 tan 0 = .149 Resistance = 54 x .149 + 80 x 0.32 F = 34 20 = 1.7 B) For C = 290 (d = 90 tan Sd = .158 Resistance = 54 x .158 + 80 x .290 9 + 23 = 32 F = 20 = 1.6 Robert Stone & Associates M f r TRIAD FOUNDATION ENGINEERING 14 Foundation Engineering . Engineering Geology Material Testing . Construction Inspection 17231 CAST RAILROAD STREET. CITY OFIINDUSTRY. CALIF. 91746 TELEPHONE 12131 966-2213 Kramer -Johnson 5569 Muir Drive Buena Park, CA Subject: Gentlemen: I INTRODUCTION 90621 Final Soils and Geologic Report Tract 30578, Lot 177 Diamond Bar, California September 6, 1977 Job #76-105 Pursuant to your request, representatives of this firm have inspected and 1 tested the fill placed during grading operations on the subject site. This report presents the results of these tests and inspections performed on tG April 14 through September 2, 1977. A plan of the site showing geologic f(1 mapping during grading, test locations in the fill, and other pertinent data is attached to this report. Reference Data Used b Preliminary Soils and Geologic Investigation dated January 14, 1977. 411 SITE PREPARATION Prior to the placement of any fill, the site was prepared for grading in the following manner: A. Surface debris and vegetation was stripped and hauled offsite. B. No trees were existing on the portion of the lots graded. C. No surface structures were present on the site upon our arrival. D. No subsurface structures were encountered during grading. E. Benching into firm natural ground was provided where the slope to receive fill exceeded an angle of 5:1. F. Native soil was prepared to receive fill by scarifying the exposed surface to a depth of 8 inches and precompacting to minimum require- ments. ENGINEERING GEOLOGI SECTION SEP14 Job #76-105 Page 2 III GRADING A. Fill was placed in 6 to 8 inch loose lifts, watered and compacted to the minimum requirements. B. The method used for adding moisture and compacting was a water truck and rolling with a sheepsfoot roller. C. Fill slopes were overfilled and cut back to expose the compacted inner core. IV TESTING' A. Compaction standard used for minimum requirement was 90% of the ASTM Test Method D1557-70. B. Field densities during the construction of the fill were performed in accordance with the sand cone method (ASTM D1556) and the drive tube method (ASTM D2937) was used on the slopes. C. Expansion tests were performed on typical soils in accordance with the UBC Standard number 29-2 to determine their expansion index. Laboratory Tests are Summarized Below Classification Maximum Density Optimum Moisture Light Brown Silty Clay 117.2 14.1 Brown Silty Clay 107.2 16.0 Expansion Tests Location: Lot 177 Soil Type: Brown.Clayey Silt Initial Moisture Content: 14.8% Final Moisture Content: 26.9% Initial Dry Density: 95.5 p.c.f. Expansion Index - 39 Expansion Classification - Low V COMMENTS AND RECOMMENDATIONS' Rough grading has been completed on the lots and fills placed under our observation and testing. The soil is classified as slightly to moderately expansive. 0& Job #76-105 Page 3 Design Recommendations A. Footing Type - Continuous or spread. Perimeter footings should be continuous with minimum reinforcement of one No. 4 bar near the top and bottom. B. Floor - Concrete slab on grade with a minimum thickness of four inches and reinforced with 6x6 - 10/10 welded wire mesh placed at the center of the slab. C. For moisture sensitive floors, a vapor barrier membrane covered with a minimum two inches of clean sand should be placed below the slab. The allowable bearing capacity of the footings should not exceed 2000 pounds per square foot, with a minimum depth of 12 inches and a minimum width of 12 inches. This value includes dead and live loads and may be increased 1/3 for seismic loads of short duration. Geologic conditions encountered during grading as shown on the attached Final Geologic Map are similar to those encountered during the referenced Preliminary Investigation. Bedding planes are favorably oriented for slope stability and all recommendations in the original report should remain valid. Respectfully submitted, TRIAD FOUNDATION ENGINEERING Frank C. Stillman R.C.E. 16810 FS/cm Enclosures: Final Geologic Map Summary of Field Density Tests cc: Addressee (4) C_ A'4 William G. Uhl C.E.G. 502 Job #76-105 SUMMARIZED RESULTS OF FIELD DENSITY TESTS Moisture Dry Lab. Relative Test Content Density Max. Compaction No. Date Location Elevation 4) pcf) Density M 1 7-29 Lot 177 893 19.9 98.1 107.2 92 2 8-1 Lot 177 895 18.7 101.8 95 3 8-1 Lot 177 897 16.4 103.3 96 4 8-9 Lot 177 F.G. 13.0 108.9 117.0 93 5 9-2 Lot 177 Slope 15.1 96.9 107.2 90 C i zz AN 1.4.W69 EGS DISTRICT ENGINEER Grading Plans, Tract.30578 Diamond Bar County of Los.Angeles 4. tt: Robert Stone & Associates Robert Stone & Associates, Inc. Engineering Geology • Soil Mechanics • Foundation Studies 19720 Venlura Boulevard — Woodland Hills, California 91364 213) 346-0565 — (213) 873-7382 January 13, 1969 68-301 0 E.L. Pearson and Associates 1551 W. Redondo Beach Blvd. Gardena, California Attention: Mr. E.L. Pearson Subject: Grading Plans, Tract 30578 Wagon Train Lane - Steeple Chase Lane - Alamo Heights Dr. East of Diamond Bar Boulevard and Pathfinder Road, Diamond Bar, County of Los Angeles Gentlemen: This report presents our opinions regarding geologic and soils engi- neering factors affecting the Grading Plans for Tract 30578 prepared by E.L. Pearson and Associates., These plans form the base map for our Geologic Map. Our field investigation was undertaken in Dec- ember, 1968 and January, 1969. SCOPE OF INVESTIGATION Our investigation included: 1. Geologic examination of existing exposures, and of exposures produced by excavation of more than 200 backhoe pits. 2. Logging and sampling of eighteen 24 inch diameter bucket -auger borings. 3. Laboratory testing of samples for soils engineering data, and engineering analysis of the stability of slopes. 4. Review of reports, maps, and data resulting from prior investi- gations of Tract 30578, and adjacent area by Moore and Taber, and by James E. Slosson and Associates. E.L. Pearson and Associates January 13, 1969 63-301 Page 2 5. Review of U.S. Geological Survey Professional Paper 420-B Geology and Oil Resources of the Puente Hills, California". 6. Study of aerial.photographs of the site. Our report presents the results of this investigation, as well. as design of remedial measures to provide stable building sites and stable roadways. PROPOSED GRADING The proposed grading is primarily to provide roads to lots which are essentially natural. However, in certain areas, especially along the outer side of Wagon Train Lane, building areas will be provided on certified compacted fill. No high cuts or fills are proposed. Robert Stone & Associates I E.L. Pearson and Associates 68-301 January 13, 1969 Page 3 1 DESCRIPTION OF PROPERTY Location Tract 30578 extends eastward and southward from the intersection of Diamond Bar Boulevard and Pathfinder Road in the unincorporated, community of Diamond Bar, near the eastern boundary of Los Angeles County. Topography Most of the tract is hilly. Ridge crests are typically 100 to 200 feet above adjoining canyon bottoms. Ridge flanks generally descend' at the rate of 25 to 50 feet vertically per 100 feet horizontally. Canyons generally have narrow V-shaped bottoms; the exceptions are the nearly flat floor of Brea Canyon along the northwestern margin of the tract and a fairly broad gently sloping canyon in the east - central part of the tract. - Drainage The northwestern half of the tract drains west to northwest into . Brea Canyon. The southeastern half drains south to southeast toward Tonner Canyon which lies about one-half mile southeast of the tract. Vegetation Most of the,tract has been used for cattle grazing. It is mantled by grass stubble. Native black walnut and live oak trees are abundant over much of the tract. Dense sagebrush covers some slopes in the 1 southern part. The valley floor adjoining Diamond Bar Boulevard has been disced. 1 1 Robert Stone & Associates E.L. Pearson and Associates 68-301 January 13, 1969 Page 4 GEOLOGIC SETTING General Description Bedrock consists of the Miocene marine Puente formation. Bedding within this formation has been folded so that it tilts variously toward the northwest, north and northeast at low to moderate angles. Alluvium overlies bedrock along the floor of Brea Canyon and in the broad canyon in the east -central part of the tract. Topsoil mantles the natural ground surface nearly everywhere. tLandslides affect bedrock in three areas where erosion has undercut bedding. Shallow slumping and deep soil creep appear to be common on some northward facing slopes. Puente Formation - Rock Types The Puente formation here consists of thinly interbedded sandstone, siltstone and shale. The relative proportions of the three rock types vary from place to place, but in general sandstone is the most abundant and shale is the least. Sandstone: Sandstone is particularly abundant in the north -central, and eastern parts of the tract. The sandstone is dominantly com-. . posed of quartz and feldspar grains with interstitial silt. It is1 firmly compacted and locally cemented. Individual sandstone beds vary from less than an inch to several feet in thickness. Siltstone: The siltstone is micaceous to clayey. It generally occurs in beds an inch or less in thickness. • The siltstone is soft where -weathered near the surface, but firm and hard where pene- trated in the deeper borings. Shale: Diatomaceous shale occurs in thin laminated beds. Structure of the Puente formation The axis of the Diamond Bar anticline trends northwestward across lots 81, 55 and 6 through 11 in the western part of the tract. Robert Stone & Associates I 1 1 1 I 1 1 E.L. Pearson and Associates January 13, 1969 68-301 Page 5 To the southwest of the axis, bedding is inclined northwestward toward Brea Canyon at angles varying from about 6 to 20 degrees. To the north and east of the anticlinal axis bedding is generally inclined toward the north, northeast or east at low to moderate angles. Undulations due to open folding produce local variations in the strike and dip. Variations are also produced be sedimentary structures such as cross -bedding, channelling and pinching and. swelling of beds. Minor faults occur within the tract. None of the faults appear to have been .active during the recent past and none.pose an earthquake hazard. Faults: Faults of apparently small displacement were observed in a few places within the tract. Steeply inclined nearly east -west striking fault surfaces with nearly horizontal slickensides are exposed on the outcrops on lots 130 and 142 in the eastern part of the tract. The fault surfaces are preserved due to silifification of the adjacent material. The Geologic Map accompanying U.S.G.S. Professional Paper 420B shows an approximately located fault trending northwest across the northwestern part of the tract to a point on lot 113 where it termi- nates against a northward trending fault. Shearing and southward dipping bedding encountered in the lower part of boring B-11 may be associated with this fault; however no clearly defined discontinu- ity in geologic structure was noted in this area, except that due to landslides. Bedding Plane Faults: In addition to faults that cut bedding, faults parallel to bedding were observed in several borings. Faults of this type typically result from slippage between beds undergoing folding. Robert Stone & Associates E.L. Pearson and Associates January 13, 1969 68-301 Page 6 1 Joints: Steeply inclined joints occur in all of the bedrock ob- served. This is normal for the Puente formation and does not constitute a special problem on this tract. Alluvium The alluvium consists of dark brown to orange -brown sandy silty clay and sandy clayey silt which underlies the gently sloping.floor of Brea Canyon in the northwestern part of the tract. This alluvium is firm below a depth of about 3 feet where penetrated in boring B-1. Alluvium, which accumulated long ago underlies the floor of the broad valley and tributary canyons in the north -central part of the ' tract. The alluvium has a thickness of 36 feet where penetrated in boring B-2 on lot 161, and 29 feet where penetrated in boring B-3 on lot 135. The alluvium consists of sandy clay silt that is firm.below a depth of about 3 feet. Erosion has removed much of the old alluvium from the valley bottom in the southern part of the tract. Topsoil Topsoil consisting of dark brown sandy clayey silt and sandy silty. clay mantles the surface in most places. Where observed in backhoe pits and borings, the topsoil is generally 2 to 4 feet thick. Ex- tensive drying cracks, common in the upper two or three feet of topsoil, indicate that.it is expansive. See the results of laboratory expansion tests given below. Landslides iLandslides occur in three areas in the western part of the tract. All are due to erosional undercutting of bedding below slopes which developed essentially parallel to bedd'ing. Northern Area: Three slides occur in the vicinity of lots 169 through 178 in the northern part of the tract. The two smaller slides are easily recognized by arcuate scarps along their heads.. Robert Stone & Associates E. L. Pearson and Associates January 13, 1969 68-302. Page 7 I However, their relatively smooth topography and the presence of large upright trees suggests that they have been inactive for a long time. The third and largest slide is apparently so ancient that soil creep and erosion have obliterated the topographic features that characterize young landslide. Subsurface exploration reveals - that the head and western edge of this slide are marked by deep soil and firm debris composed of bedrock. At boring B-15, lot 24, disrupted bedrock terminates along a shear surface at a depth of 20 feet. This is apparently the base of the slide; below 20 feet the strata appear to be undisturbed. In boring B-11 the slide base was not identified due to the presence of faulting and folding interpreted to be of tectonic origin. In borings B-13 and B-14, the base of both the younger and older slide is interpreted to be at 40z feet and 37 feet, respectively. In Moore and Taber boring B-29, they interpreted the slide plane as being at 48 feet. However, we interpret the slide base to be at about 30 feet. The slide plane they reported at 48 feet is probably a bedding plane fault of tectonic origin. Evidence indicating it is not a slide plane is as follows: (1) if projected northward at the reported dips of 14 degrees in boring B-29 and 20 degrees beneath boring B-41, it would be more than 100 feet beneath the surface at the toe of the slide, and (2) if it is assumed to be the_same shear.plane as reported at 65 feet in Moore and Taber boring B-41, the shear plane would have an average dip of only 8 degrees, an inclination that seems too low for sliding in these materials; in addition, this 8 degree inclination is not consistent with the dips reported in the borings. Cross -sections M-MI, N-N' and 0-o',accompanying this report, represent our best interpretation of the configuration of the three landslides. Robert Stone & Associates L. Pearson and Associates 68-301 January 13, 1969 Page 8 iCentral Area: The landslide in the vicinity of lots 46, 47 and 48 is controlled by a synclinal undulation in the northward dipping strata. A soil -filled graben was exposed in two backhoe pits at the head of the slide. Although no slide plane was recognized in boring B-26 by Moore and Taber, our interpretation places the base of the slide at about 20 feet at that location. Bedding upslope from the head of the slide strikes directly into the slope and should provide adequate support for residential structures. The landslide in the vicinity of lots 51 through 54 is also controlled by a synclinal undulation in the northward dipping strata. The slide is 31' feet deep where penetrated in boring B-27 by Moore and Taber. The configuration of the slide is shown in cross -sections I -I', J-J' and K-K' along with the remedial grading designed to support the area upslope from the slide. Southern Area: In the vicinity of lots 58 through 68, the natural ground surface slopes toward Brea Canyon at an angle equal to or slightly greater than the inclination of bedding in the underlying e strata. There are no scarp or other well-defined physiographic evidences for landslides in this part of the tract. However, a soil and debris -filled graben was exposed in our backhoe pits on lots 61, 77, 78 and the adjoining roadway. This revealed the existence of an ancient slide. The graben is 7 feet wide where exposed on lot 78 and only slightly wider to the southwest. This suggests' that the'total slide displacement was small, on the order of 10 feet. Our interpretation of data from borings B-7, B-17 and B-18, and from backhoe pits indicates that the slide has a maximum thickness of about 30 feet within the tract. The configuration of the slide is shown on cross -sections F-F', G-G'.and H-H' along with remedial designs. 1 1 Robert Stone & Associates E. L. Pearson & Associates January 13, .1969 68-301 Page 9 1 1 slumps Shallow slumping appears to have occurred on many of the steeper northward facing slopes. The slumps are indicated by hommocks below small indentations in the slope.. They probably formed during exceptionally rainy periods after the soil and underlying weathered bedrock became saturated. Material affected by slumping is generally poorly compacted and subject to creep. It must be removed prior to placement.of compacted fill. If it. is left in place, foundations require specific design for the specific site. Groundwater No springs were observed within the tract during the course of this investigation. No groundwater was encountered in any of the 18 borings made by us and none was reported in the 7 borings made by Moore and Taber during their earlier investigation of the tract. u n J 1 1 Robert Stone & Associates E. L. Pearson and Associates 68-301 January 13, 1969. Page 10 1 SOILS ENGINEERING Soils engineering analyses were performed to determine (1) rotational stability of the steepest natural slopes and (2) design of compacted fill shear keys where these are required by unfavorable geologic conditions. The locations of the proposed shear keys, slide removal and recompaction, and buttresses are shown on the cross sections and geologic maps accompanying this report. ROTATIONAL STABILITY Natural Slopes: Stability analysis of three of the highest and steepest natural slopes were performed. All three of these analyses show Factor of Safety well above 1.50. Strength values used in our analyses were derived from laboratory tests on saturated samples of typical materials obtained during our investigation. The analyses were based on the conventional method of slices. Proposed Slopes: Because proposed grading will be limited to low slopes necessary for roads, we deem analysis of these slopes to be unnecessary; our rotational stability.analyses of much higher natural slopes show adequate Factors of Safety. Shear Key Design and Slide Removal To correct unfavorable geologic conditions, compacted fill shear keys have been designed to support bedding on lots on the outer side of Wagon Train•Lane (See:Sheet:3). All the shear keys have been designed for a minimum Factor of Safety of 1.50. tWhere slide material is present, removal and recompaction of the debris has been included in the remedial design. This occurs on Wagon Train Lane and Steeplechase Lane. 1 Robert Stone & Associates E. L. Pearson and Associates 68-301 January 13, 1969 . Page. 11 This remedial grading is designed to provide buildable areas 100 feet wide on each of the lots, as well as stable roadways. The buildable area would be uphill of a 1:1 plane projected up from the toe of the key (or a lk:l plane if a fill is built above the existing ground surface). Calculated Driving Force: Driving forces were calculated for a wedge resting on the potential failure surface along the.bedding plane, from the rear of the shear key uphill along the plane to its intersection with the existing ground surface (or proposed grade). The driving force was computed as the inclined component of the weight of this wedge acting along the plane. Resisting Force Along Failure Surfaces: Resisting shear strength parameters along potential bedding planes are based on laboratory tests described below, made on remolded samples of plastic clays obtained from a pre-existing failure surface. The parameters assumed in our design are as follows: 0 = 9.0 Degrees C -u 500 lbs/sq.ft. Compacted Fill Shear Keys_ Shear keys have been designed in all cases to extend through the lowest potential failure surface to a surface where bedding is supported below the canyon bottom. In ecertain cases double shear keys have been designed. The upper key is designed to support unfavorable bedding within the upper portion of the slope, and the lower key to support the entire potential slide mass. Shear strength developed by the compacted fill keys'was calculated as the cohesion and internal friction of a column of soil overlying the potential shear surface. The total resistance was assumed to consist of the resistance along the failure plane and the resistance of the shear key. - Shear strength of the compacted fill was determined by laboratory tests on saturated samples. Typical shear key designs are shown.on the attached cross -sections; our calculations are attached. Robert Stone & Associates E. L. Pearson and Associates 68-301 January 13, 1969 Page 12 Compaction of Soils in Slide Areas Consolidation tests described below were performed on typical undisturbed samples of soil -like materials obtained from within the slide zones. The tests indicate that these materials are well - compacted from a soils point of view. However, we have designed the shear keys, buttresses and remedial grading to include removal•and recompaction of slide material from the roadways,_ 1 and extending far enough from the road to provide 100 feet of buildable area. Buttressing In addition to the shear keys described above, an equipment -width stabilizing fill will be required along the 'south side of Wagon Train t Lane, between the west end of the tract and Lot 79. These cuts, a maximum of 24 feet high will daylight unfavorable bedding (dipping about 126 to.140). Recompaction of Existing Ground tThe existing surface soils in building areas include mainly dark brown silty and sandy clays, which are dessicated and cracked to a depth of 24 to 30 inches. These soils should be cleansed of vegetation, brought to proper moisture control, and recompacted to a minimum of 90 percent of the laboratory standard prior to being used for support of foundations, or appropriately designed foundations be engineered for specific buildings on specific sites. The soils are expansive. Recommendations for design of suitable foundations are given in our "Conclusions and Recommendations". e Robert Stone & Associates E. L. Pearson and Associates 68-301 January 13, 1969 Page 13 LABORATORY TESTING Classification Soils were classified visually according to the Unified Soil System. Classifications were supplemented by index tests, such as hydrometer analyses, mechanical analyses, and Atterberg Limits for representative specimens. Unit weight and moisture determinations were performed for each undisturbed sample. Results of density and moisture determinations, together with classifications, are shown on the Logs of Borings included in this report. Laboratory Standard for Compacted Fill The maximum density and optimum moisture content was determined for two major soil types encountered in the borings. The recommended laboratory standard is ASTM:D-1557-64T, modified to three layers. Moisture density relationships obtained for these soils are shown on the attached curve. Direct Shear Tests ` In order to determine the shearing strength of the soils, direct tshear tests were performed on representative.undisturbed andremolded. samples. Samples of remolded fill were tested at 90 percent of the laboratory standard. To simulate possible adverse field conditions, the samples were saturated prior to shearing. A special saturating device was used which permitted the samples tested to absorb moisture while prevent- ing volume change. Graphic summaries of the test results.are attached. I I Robert Stone & Associates E. L. Pearson and Associates 62--301 January 13, 1969 Page 14 Testing of Slide Plane Material To determine shear strength parameters for resistance along bedding or shear planes, our field engineer obtained hand samples of typical materials from the shear surface observed in Boring 41 (made by Moore and Taber, Inc.) at a depth of 62 feet. To assure that the moisture contents of the samples were typical, the outer four to six inches adjacent to the hole were removed before samples were obtained. Composition of the Samples The samples consisted of pieces of shale and siltstone in a matrix of plastic clay. Laboratory examination of the samples indicated that the plastic clay matrix would exhibit much lower shear strengths than the samples as a whole. To obtain a conservative.set of shear strength parameters, we therefore, reconstituted a single test sample 1.00" high by 2.62" in diameter) using only the plastic clay matrix at field moisture and density. Test Procedure and Values This single samplewas then cut to form a pre -determined shear plane and sheared three times at progressively increasing normal loads. The resulting values are as follows:. 9. 0 Degrees C = 1100 lbs/sq.ft. Since the cohesion could depend on moisture content, however, and because moisture and drainage conditions might be different in other portions of the slide plane, we have used a lower cohesion value of: C = 500 lbs/sq.ft. in our analysis. 1 0 Robert Stone & Associates I I 1 1 1 1 1 1 1 1 1 1 1 t 1 E. L. Pearson and Associates 68-301 January 13, 1969 Page 15 Load -Consolidation Tests To investigate the settlement of soil -like materials within alluvial and slide zones, five load -consolidation tests were performed on an undisturbed sample of natural ground. Axial loads were carried to a maximum of 8000 lbs/sq.ft. Moisture was added in each case at an axial.load of 4000 lbs/sq.ft. to hasten consolidation and to simulate possible adverse field conditions. All of the samples tested were found to be in a well,compacted condition and exhibited very low compressibility. Expansion Tests Potential expansive action of two typical soils was 'studied by remolding bulk soil samples to 90 percent relative compaction. The samples were then air-dried, and saturated for 24 hours under a surcharge of 60 lbs/sq.ft., the approximate load imposed by a four -inch concrete slab. Results indicate that although the sand- stone and siltstone bedrock is non -expansive, the upper existing soils are moderately to highly expansive. Our results are attached; suitable foundation design parameters are given in our "Conclusions and Recommendations".. 1 Robert Stone K Associates I E. L. Pearson and Associates 68-301 January 13, 1969 Page 16 1 CONCLUSIONS AND RECOMMENDATIONS 1. From a geologic and soils engineering standpoint, Tract 30578 is suitable for development as shown on the grading plans prepared by E. L. Pearson and Associates. These plans form the base for our Geologic Maps accompanying this report. 2. After the grading, which includes construction of compacted fill buttresses and shear keys, as well as removal and recompaction of some slide material, each.lot will contain adequate building area. The roadways will be on stable bedrock or on certified compacted fill. 3. The rules and regulations of Los Angeles County require geologic inspection during grading and submission of a final geologic report. If at the end of grading any areas are left with significant unfavorable geologic conditions these must be called out in the final report as not suitable for normal development (i.e. as restricted use areas). Of course, the specific plans for each specific lot must take the topographic geologic, and soils conditions into account, and must comply with the rules and regulations of Los Angeles County. At the present time, the only restricted use areas we anticipate are as follows: Off Rim Fire Lane -- Lots 34', 35, 36, 37, 38, 39, 40, 41 and 42, the slide areas shown on Sheet 2 of our Geologic Map are restricted use areas. 1 1 Robert Stone & Associates 1 E. L. Pearson and Associates January 13, 1969 68-301 Page 17 Off Wagon Train Lane -- Lots 46, 47, 48, 49, 50, 51, 52, 53 and 54, as well as lots 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67 and 68 have restricted use areas beyond the 100' wide buildable area extending downslope from the outer edge of the road. This 100' wide area will be stabilized by remedial grading which.includes construction of shear keys and removal and recompaction of slide debris. Off Steeple Chase Lane -- Lots 167, 168 and 169 have a restricted use area beyond the 180' wide buildable area extending from the outer edge of the road. Lots 170, 171, 172, 173, 174, 175, and 176 have restricted use areas beyond the 100' wide buildable area extending downslope from the outer edge of the road. This 100' wide area will be stabilized by removal and recompaction of slide material. 4. We understand this tract will be sewered. 5. The underlying materials include expansive soils. Expansion tests should be made before individual foundations are designed. For typical flat pads or gently sloping lots we recommend the following foundation designs: Foundations --.Exterior and interior foundations 18 inches deep, and continuously reinforced with one No. 4 bar top and bottom. Slabs -- Soils beneath the slabs should be at or above optimum moisture content to a depth of at least 18 inches,'and should be compacted to 90 percent of the laboratory standard. Robert Stone & Associates 1 E. L. Pearson and Associates 68-301 January 13, 1969 Page 18 A moisture barrier should be placed beneath the slabs. The slabs should be 4.00" thick, and reinforced with a minimum of 6x6/10x10 welded wire mesh. As noted in the body of our report, the upper 24 to 30 inches of existing soils in building.areas are desiccated and cracked. These should be recompacted to a minimum of 90 percent of the laboratory standard at proper moisture content before they are used for support of foundations. 6. Compacted fill is to be emplaced on the tract. Prior to the placement of any fill, all debris and surface vegetation should be stripped and removed from the site. All unsuitable material should then be removed to firm; natural ground or bedrock. 7. Soils used in compacted fill should be cleansed of any debris, brought to proper moisture content, and recompacted to a minimum of,90 percent of the laboratory standard ASTM D:1557-58T, modified to three layers). 8. on slopes steeper than 5:1, a minimum width of 12 feet of compacted fill is recommended. The base of compacted fills should be founded in horizontal benches cut into firm material. The heights of benches should be controlled in the field by the soils engineer. 9. Fill slopes should be compacted to 90 percent relative compaction t to within 6 inches of the finished fill slope. The outer 6 inches should be compacted to a minimum of 85 percent relative compaction, under our control by grid rolling or an alternate method (subject to our approval). 10. Compacted fill buttresses will be built where street cuts under- cut inclined bedding (or the cuts will be flattened to correct the situation). Robert Stone & Associates I I I E. L. Pearson and Associates 68-301 January 13, 1969 Page 19 11. The fill slopes should be planted and maintained to minimize erosion. 12. We are available for consultation with you or officials of the County of Los Angeles at your convenience. We appreciate this opportunity to be of service to you. Very truly yours, ROBERT STONE & ASSOCIATES, INC. By Robert Stone, Ph.D., President and by - (O /t%c- W1 L Perry L,/ lig, Ph.D. Er;Jq'r. Ge logist and by Gerald Gor'ian, RCE 14698 RS:PLE:GG/dwt Distribution 4 E. L. Pearson and Associates 4 County of Los Angeles Enclosures: Geologic Map Cross Sections Buttress Calculations Logs of Borings Laboratory Data Robert Stone & Associates J 1 U v YI Y Y n l F N I Y, r Q :I A A v v CIJ nun N G r o 0 H fUl 0 t E' i Ci 00 p0 JOO 1Hu0 u J I' IMF H pNW l; CLy U FIFPJ. IL ff, L l" a I I I i• a v l i 1 7 IIC` v U O.: IW F2FUWmcoF/( ii E. H V, V' f4 l II I i OHMN H V H III HV, cco. .. I N I i I 4 n I 17 po f H I I I I M j H O ?: E' M I n E I I i I I I IIj? j: • I I I I I I c\ f Nl to 7'. I j(U i C C C a n fl yl4y Ja, a. yay L C U yls LI C J rC I Q N 1 O CN F a H W rr. r I IjI 5 I I C. 1 N N OU U I 0 H I u Z l rnHuFu to COII V corR C.0 loI C i I Y C N I X 0o` I N H hh 11 II0Q H H N 0._ y p I 1 I I H j v i off I OH m In 9 f-, 5l O iO O N JH co r O i I I I I I II1r Iso fi n I' j A f- IU 1 i F- L I OF J Q H H 0U i y 4 o o O a I IH -Hro N 0 0 0 IGl rv-f F U F H I C v I1ul 1 co 00 0jco 0 I I aI-, m lhlvi I I Y O Q I O j I y y M o i Ii f r1 M F n I LQ I I II I 1 i I I P1 I 4 oacc 1 F G Qf0 O, O O J U y y V V v n L U 7 Lo r n I F F v N N C l U i0 4700 leao j 1 cc U 1 hlL 1 f I I I C yO v% f U •< C.l U u C o r' G VI VVi 11tiO J1 r i j r I I I 0 0 O I— x c 4 H 1 O00 Ol N_ v Czu0N I I I 1: 2acnt` M o i I t H IsyaIII1VlI 7: r~ 1 I Ln H Cq I c0 CO o IV) I i i I I I II I I I I • I I 4X 11111 I I 0 I t ' 1 I o cH F+ I V7ylil 1 C tCV OI J O J a o a aoa o eft ; i H N 4 E CIC. u CC W 0a U H n fbl z L i4 M 1-! Ll C I• I I i a Imo') r._ .: i I I I` I I I FC I•• I i Imo• U• C• F •S p• H CILn y r M I M 0 r— u 1 I E4 0 F cy0 I l) to ff Ll N M II co o H L J ao F F i o vi to Ino n. nl. N i I I I 3• ir• l 0 I I i I a l b I I 1 M 11 V 9 c• C t;N N a\ u c\ m N II_.I I I II 1 U U U C r a r~ V H1ryYOcoti O y, ;l• i G i MW f J Z fI O O U 11 r r I I I I i r I r I 1 0!u IEsc: in i f r- O H '• H H O H H M inan nl 6 N Q• U O I I o I ll: I i O o ICO0 1' I11- Y `J U O oo` N M Ci 1 1 O0 G TO G 0 111O 0 M : •, C 1`n I f 1 j` I U i I r 0 0 o c 00 o 0 o C9 o m m C7jQ Cd a__ , Z ON j O 0 0 0'0 O m N G a - :.5 c \ M )(,j-rA-7ioc.a5 S-'oR YAQ )A,E 1 Exc,gvrt-I'to aGTto[l tII A t p. A G,, E _ 1 Ihoo toQ 72-0•,Ooo' N C 8O Zv o 6 0 o c L 2001 3 7 00 O G Cn l O 2 tC O z- 0 0 Oi 61 3 o O 1 rr j2 o Go I 19,g o 0 o 1.- zoa -rs 15"00C, 1 1 I G tip UNl i'3v aRRFss SHEAR-K6'y S Goan pflcTlo 1 I A1 ovE liGQovr t EVEL Z FOOTI-TOT AII- S%Co00 NCA•., A-TION F ok- F'CW3-C,RAKJC- R f J TOTAL- 000. 0 0_ i S Oo0 I I QAr",—VI 3 Aoa & 8 ez I Rc\S CEFQEQ@CE — eWGG-T -Z5 GxGkvA-v- oM ARE A | \4\ A co A@l6sio» ASo,LF Qo jw& &QVEL7 E | vwR bAa G 2' t0 O 0.9 CGS i yo SOILS ENGINEERNG DATA Typical Fill Materials t MAXIMUM DENSITY CURVE M Moisture Content in Per Cent of Dry Weight LOCATION BoringNo-..__...4........................... Depth, in feet ... .... 20..r..I.... I ............. REPRESENTATIVE FOR Remoled Puente Sandstone and Siltstone SOIL CLASSIFICATION Soil Type and Description — l Sys Poorly Graded Silty Sand METHOD OF COMPACTION ASTM Standard Test Method D-1557-64T(Modified) 4" Diameter mold; 1/30 cu. ft. volume 3 layers 25 blows per layer; 10 lb hammer. dropped 18 inches OPTIMUM MOISTURE CONTENT, In Per Cent of Dry Weight 15..0................ MAXIMUM DRY DENSITY, In Pounds Per Cubic Foot ......1..16.0..... ........ ...... GRAIN SIZE DISTRIBUTION Sieve Sizes -U. S. STANDARD 10 16 40 100 200 Hydra eler100 111n11 IIn11 w1111 IIIIIII IIIIIII mm1 1n1r11 1111111 111111 1111111 1111ni 1111111 1111111 1111n unit 11111t1 1111111 101 1 1111111i 1111111 111n11 1m 1 11n111 t1111111 Illn 111I 1 11n111 w1111 IIIIn1 a111111 n11t1 11nI 1111111 1n1111 11n111 1111111 1111 ATTERBERG LIMITS Liquid Limit"N.P. % Plastic Limit N.P. % Plastic Index N.P. EXPANSIVENESS Swell from Air Dried to Saturated. Remolded to 90% of Laboratory Standards. Surcharge( lbs./sq. ft.) 60 , 400 ; 650 CoarsG Mediumv y• Fincy 1" %$ well 2_6 Gravel; Snnd Send i Snnd Silt I Clay— SOILS ENGINEERING ®fi.6"A i 1 Typical Fill Materials LOCATION BoringNo—....,7............. ................ Depth,'in feet.. Surface ............. MAXIMUM DENSITY CURVE Moisture Content in Per Cent of Dry Weight REPRESENTATIVE FOR Upper Natural Soil I I 170 - t I j SOIL CLASSIFICATION 105 Soil Type and Description — CL o I ! s Silty and Sandy Clay METHOD OF COMPACTION ' ZI! ASTM Standard Test Method D-1557.64T(Modified) 90I_ ... - ' -- e" Diameter mold; 1/30 cu. It. volume I .3 layers 25 blows per layer; 10 Ib. hammer dropped 18 inches 5 10 15. 20 25 OPTIMUM MOISTURE CONTENT, In Per Cent of Dry Weight 20.2... MAXIMUM DRY DENSITY, In Pounds Per Cubic Foot 97........................ i GRAIN SIZE DISTRIBUTION Sieve Sizes -U. S. STANDARD t t tt tt Nli ntn:1 IIIIIII IIIIIII t1111 11111111 lIn11I IIIIIII IIIIIII IIIIIII Im ul IIIIII IIIIII`IIIIIII IIIIIII IIII I IIIIII IIIIIII IIIIIII\IIIn1I IInIII IIIIIII IIIIIII nA111 pall IIIn1I IIIIIII IIII. nIIIII IIIIIII IIIIIIn IIIn11 r IIIIIII IIIIII IIIIIII IIIIIII IIIIIII IInIII IIIIIII IIIIIII r Porlicle Diameter- Millimeters* tineGravel;5ond S nidMedum i Sand Silt j Clay- 0 1 ATTERBERG LIMITS Liquid Limit 47 1 Plastic limit 79 1 Plastic Index 22 I i EXPANSIVENESS t % Swell from Air Dried to i 'Saturated. Remolded to 90°/. of. Laboratory Standards. Surcharge( lbs./sq. ft.) 60 400 . 650 Swell 8.40 jos No. 68-301 1.. —I Stnne & A :nciatPc AEBUL'TS OF SHEARING STRENGTH 'TESTS 1 i 9000 0001 i 6000 i H Cn an N 5000 m_ i r cc n 4000 rnc 0 LN i 3000 1 i 2000 1 1000 1 i Bulk Samples Remolded To 90% and Sa?ura:ed ii i O 0 1000 - 2000 3000 40110 50110 ,6 i EXPLANATION: Nocmol Load(LBS/SQ FT.) 8-9012'- Somplo taken '"from ' :,.ROBERT STONE & ASSOCIATES Zorinp 9 u1 i7 Feat in 000tit Job No. 68-301 , RESULTS OF SHEARING STRENGTH TESTS Undisturbed, Saturated Samples 4000 RIENTE S NDSTONE I m 3000 2000 B6 @ 20.. 33' 1000 --... —t— rn 0 i.. o = 34' 2000 C 700 psf l000 a 0 1000 2000 3000 4000 5000 6000 Normol Load(LBS/SQ FT.) EXPLANATlOM B-9@17'= Somple taken from• ROBERT STONE & ASSOCIATES, INC. Borinq'9. c.r 1; Peer. In Depth Job No 63-301 RESULTS OF SHEARING STRENGTH TESTS Undisturbed, Saturated Samples 4000 SANDY CI AY SYBSOI L 3000 _ 2000 O- B15 @ 5' C 17' 1000 C_==-800 W m 4000 c PUENTE SILTSTONE & SANDSTONE f a• 3000 z000 — B15 @ p . I. 350 C = 550 Psf 1000 ... t0 0 3000 4000 50I 60001000 EXPLANATION: Normal load(lBS/SO FT.) B-901'= Sample taken Isom •::+• ROBERT STONE & ASSOCIATES, INC. of 12.FeeY' Oeplh Job NaBoring•9 68-301In _ 40c 300 J. 200 100 V) Nm ' 406 O1. 0 0 300 RESULTS OF SHEARING STRENGTH TESTS Undisturbed, Saturated Samples 17 @ 10' 33° 2000 —._... I Q=670 sf• 0 1000 2000 3000 4000 5000 600C Normal.Lood(LBS%SQ FT.) EXPLANATION: ROBERT STONE & ASSOCIATES, INC. t'• B-9@12'a 5ompte taken from Job NO. '08-301Borinq'9 W 11 Fett In Depth.. ss r•:AJ' I E- 7 J :0"'7'._'C::-:ll il• y._ti1 ' J 7 Undisturbed Samples at Field Moisture EXPLANATION: Normal Load(LBS/SO FT.) B-9@ 1Y • Sample taken from ROBERT STONE 6 ASSOCIATES -• Boring 9 at 12 Feet in Depth. 10b No,68-30% 1" 1 c 0 C 6.0 x 4.0- z.o C0 4.0- 6.0- 0 a a 8.0- 0 co lo.o- 1 d 12.0- i 14.0- 16.0- 18.0 L®A© C©MSOLQ®A-TOCNI u F-S 6 S i.. IT. f.. . _. il... . III i:...E.:. .I Ld..l.:.`a..i i I 11 I I I,; I IIII I I Illi I TI. I I 1 I I I I •I 11 I+' I I'.._fI w I. I i1 L. i..i ifl,_jIj::i.!:.: I; I ffI'..r' L..+. i:.l::. L t. aliri:' 1. Lii: I1„-I:I 1. t iL!.!......;.:-L. I . I i tl,!':J 1I •i' fi!I, Ii...l ..' 1 I;... I 71 I:.I'. Il.l.:.r i'i:rl.: I I_ i•r; 1: it. r;i IL..,.....u•,;, I III Ii,.. LI.I I i, - f I I 1 I11liiTi I I I I s I t I:::f::.i;. t ` : I 1_;: .; . I IL_ 11`-i,' J' ' I I fil II I , I• 11'I I 11• j'I 1. 1 I I:......... I::' I' I i:!.E. it i iiil LI I: It15 1 1E ;-, . i!; t L.. 1{ ii; i • "'7...j.;.....i... I,..• III I I ii: l f i Ir f I .' I . I'.. I I , II I j ! II I I I I I I f• i I { : . • Ii. I•.: ;• i 1 ' I: I I I I I! I I, i•. 1p I I. III .. {: 0 0 0 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 N Iq O N p p O O O N t1 O N O O O O 0 O O O 0 0 0 Normal Load(LBS/SQ.FT.) O FIELD MOISTURE ROBERT STONE & ASSOCIATES. 0\, EFFECT of ADDING MOISTURE Job No. 68-301 REBOUND - - 1 0 1 NC 6.0- aO. xW 1 4,0- U 1' z.o- 4.0- 6.0- 0i •° s.o- o 0 10.0- V 12.0- v, ao 14.0- 16.0- 18.0- L®A® C©NJSOLODA79ONJ TES;Y5 I :I: I I I 1 I - I j I , • I i L:; i , ::,1- 1. I J i I.'ll: f i i L I I I P. I—* I FA1 T;11 ! ir r F I .iI 11. I!,LII!II 1,1.1 1 II I II II, I jiff I I ;II I I. I. l i I I I 1 ILj L.J1 I I r 1 7 I I I L. 11"..... LLI; I:. la i..l.l I J. i.• I i I I I" I !• L..I, 11 I. 1; I I 4 i ,'., I IIILjI_ I I• I.. 1 0 0 0 0 00...,0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 rr a .n o o n a0 00 0 0 0 0 Normal Load(LBS/SQ.FT.) 1 O FIELD MOISTURE ROBERT STONE B. ASSOCIATES EFFECT of ADDING MOISTURE Job No. 68-30 REBOUND r o c 6.0 Oa x W 4.D U V 2.01Lva! moo 2.0- 4.0- I! 6.0- C O B 8.0- O o 10.0- d 12.0- V L' a.14.0- 16.0- LOAD CCP\ISCLI®AITEON -rZ—S u !S r I I;::..I:...: I- 1 f I I I..i'lil: I is ..i.I r I I 1l'I 11 i! r 1 I iii'i I I;:.i; I ii 1 I I.T. I,„.. 1 1 1 I, t I i I .. 1_ II I I III'LI I I iIP r 1'I 1 I r I III Ii.:. J 1 I ~I 7 i ... LI! 1IIIIlr'I I 11 I I i I 1 I I I I 1 I rIII I LI I III 11 I r I 1 I I I I n 1 d I , I I I 11 I 1i I 1 III. I Il.—, 111Iil I tl. Ill III I,I J, I;I 11' II',' r< '—i• J' I J 1 Ill{III. I I{.. I' r it I {i141 I l,I ,1 I j rrll I li r l r I I I III" Ili 1 1 I i r l I I' II jII L llil:. it llll I i','i { 1' 1 1 I f 1 I I I III(. 11 L;IIi 1, 171 Ir 1 I 1; 1 1. II Ii..l rrr.. ....1. L.. I dl'.:, 1 I• I I I:':.L I:I 1 I• I j 1 • I :. i... ..I 1 I I 11I li IIIII I 1 1i.LLl. J I I1 I I I I hl I 4, l.' I,I I., rllllr •1 I111II.1 r i.i I I1 0 0 0 0 0 0 o o 0 0 o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 n 1'I V N o 0 0 0 0 0 0 0 0 0 0 Normal Load (LBS/SQ.FT.) O FIELD MOISTURE ROBERT STONE ASSOCIATES O EFFECT of ADDING MOISTURE Job No. 687-301 . REBOUND O_®A® CONSOILO®A-TOON u. LES7S 0 C 6.0- I1D , ' I'•I I I '`I '' (' I Ili 1 I'llIIa ( + 1 t I 'I ill 1 II' II rl'i IIIIIII I J + AliI % ;i W 4.0— ._ - I ,— i+ 20 0' i, l 7 I 20 I, l I{ 4. 0- + li III i ' lrI I I I O C I I D B.D— O O 10.0- I 1 , LIIIIL d14.0-T per. I l L 1 Ii I1 I 16. 0-- IIII II L."I I.I I,II I I , j1. r `. 1 I {` ,IrIII IIII I' I II t I I I , I' .I 1I _ I I , 1 I I I I I I I 1 I I I I r a I I d 1 O O O •O O O O O 0 3 O O O O O O O O O O O Q N O H 17 Q vOj O N O O O O IV 17 Q N Normal Load fLBS/SQ.FT.) O FIELD MOISTURE ROBERT STONE E; ASSOCIATES A EFFECTof ADDING MOISTURE Job No. 68-301. REBOUND I ,..., L,.,•. '.,.; I li I' I I. I I.: i.: j t..: I. i.:j^'ili:il ail Il., il'I L:, I II L L.. i ii! i L:6..i; itii I:,, jf. 1 I I I, i l j I. l L'I:i'i ::..... L..:-, I`I. 1 Ii'',.., , 1 J { I 1 i.ii j. I L. 1 ! 4.'_..i.-L.i. I...,. I.i L.: j r i:::: is f j' it I i J:3 l}' 1 f! L:i:l i' I I:i':':I::: i:: i_J!.;j: 1!; F_{- I I i I I! Ii I :. I I i iif I i I III; I 1 1 V I I Ij.;':'.I i• ''•: I :: (`ill I iI j i I I i, eJ' El',1 X.. J: Ia.'i:..:;iji i::.I:. I 1 : ':.:.i :J.:...1 j, I ! IIII+' I LI_r i11I I1'•• r•j I i I l I 1 1! 1 D p^IIBSIO@1`30If '] L. L,Illrl '., III",•'j„j., 1':: l l!;V:"I iii-j.• 1I:,•. il i!:, rJ:;,:. 1 il _i%Tl I I , i I1 ! Cj;.•,. ::i.._, I.I:.;1 1 I'I"I,' I„ it;ll;r•:.I E'°`:L. I!= n !!!' I ill 1' el '. I.jl: I'll11: li. I i i 1 I1! f i ar' j:an:. ii i. 1•: ` 1 ai. ...:I i' n, - I f..; L i..•.!...1. I i.,I! L i•j- I.: {1 I Ii I.1:`:Ir-..,.:. 1 III i I I II I I JI l II I Ir ICJIFyI II7j O C O 0 0 O O O O •7 b O pO O O O O O O O O O ry O a n O O o p O O O O O O O 0 0 N Normal Load(LBS/SQ.FT.) O FIELD MOISTURE 0 EFFECT of ADDING MOISTURE - ROBERT Job STONE No. E?< ASSOCIATES 68-301 REBOUND SUE-SU.RFACZ DAYA Log No........1........................... PROJECT: ........ ...... Pe................................................_.....arson - Diamond Bar - Tract No. 30578 Alethod of Drilling:....... i4n....................................logged by ........ M.ER................... Job No. ...... 68.-30.1..................... Ground Elevation;.......s.± See Map 12/24/68location:...............,..................................................................................Date Observed: .......... ............ _....... o-A ti h J A b2 + O` O`'\` ° by o°` SP q yP 0`02 off° 240[ ` DESCRIPTION SO IL TESTS J J of v TOPSOIL: Brown -dark brown, silty, a slightly sandy medium to plastic CLAY CL Illllll 12.3 106 with some sandstone fragments dry, cultivated to l'; moist, firm 15.3 105 SUBSOIL - ALLUVIUM: Brown silty mediun 1 IIIIIII CLAY with scattered shale fragments moist, firm to stiff but slightly CL porous) c Dark red brown silty medium to plastic CL II111 17.2 113 CLAY (moist, stiff to hard) Some hairline cracks IIBM 18.6 106 Locally porous a I wn sandy CLAY (moist to very moist, ff)with sandstone and' shalerafrofi g ments.. I t CL I 11111111 1 19.51 106 I Total depth 26'.' No ground water,_no caving.' g I LogNo.......2......._....................... PROJECT:........P2arSOn - Diamond. Bar...- Tract No. 30578 Method of Drilling: ........ 24" ..... Bucket-auger Logged by.....1 Fr .....................Job ho.......8.-. 0. ...................... Ground Elevation: ....950.t..................location: S M.......... ........................................ Date Observed:_12/24/68.. Ot °F 1 ` c `; qi' O ovO Q`0 J C Oo- n DESCRIPTION SOIL TESTS ALLUVIUM: Clayey SILT ML! ry, J.rm, porous) r JCL TOPSOIL: Brown plastic CLAY moist, stiff -hard) 5 CL I11111 15.3 110 SUBSOIL - NATURAL FILL: Red brown sandy CLAY moist, stiff, slightly porous) lmulIIIIII 13.8 100 Reddish brown clayey SAND and SILT moist, firm) t ML i, Brown to dark brown sandy SILT -CLAY moist, firm) 3 Mottled orange, brown, tan silty SAND SC. IIII 19.1 105 with interbeds of SILT and CLAY. CL moist, medium -dense) tMottled grey, orange sandy clayey SILT (moist, to very moist, stiff) CL Illll 14.4 1.04 Merges between sandy silty CLAY and sandy clayey SILT 16. 3 1091111111. 35 Continued @ 351 c\ 5ov^•_5e=,r•r.r,^,_ ^ar.-• T '1'. 2 Cont' ROJECT:....... Pearson....-... Diamond.... Bar....-...Tr1.act..No..:....30578................:............................................................................... Method of Drilling: .... 24.... ...Bucket-.auger.................................Logged by ........ M a .................. Job No.... ... 6,8•-30.1..................... Ground Elevation; .......9.50±........ Location:............................................................................ Date Observed; 12 24 68 OC `` P, J ,,, 'O Y; p 02 e, a i' DESCRIPTION SOII. TESTS rT. j Same as before BEDROCK - PUENTE FORMATION: Yellow i brown, orange, grey SHALE, SILTSTONE t and some SANDSTONE bed SM { Good bedding @ 37':N80 W,21oNE Jto Total depth'411. No ground water, no caving. i tSUB -SURFACE DATA '"a, No . ...... 3 ............................... peaKs.o.n .... ...... D.i.am.qnd ... Ran., -,,,Tract„ T.r.a.c.t. ... No ...... 12.0-5.7.8 ..... I .......... .. Diamond... .... .. .. ... .. .. ... .. ... .. .. ... .. .. . .. .... . ... ... * ... *** ...................... Method of Drilling: .... 24• ...... Bucket auger .........logged by....-MER .....................Job .................... Ground Elevation: ..... 1.0.2..5..± ............. Location: ........................ ....... I .................................. Date 0bsorved;..1...2...-/27/68 1 1 q DESCRIPTION IL 19STSSO TOPSOIL: Dark brown sandy SILT withMLIIsomeorganicfragments I Zver moist to 1', slightly moist-moi.,t, KL ro s. belo ALLUVIUM: Brown sandy SILTto slightly moist, firm, porous) CL 7.1 107 Red brown sandy clayey SILT to silty clayey SAND Sc moist, firm, slightly porous) to 9.5 103 CL 11111 111111i, 12.8 108 IIIIII 13-2 110 19.0 101 BEDROCK PUENTE FORMATION: Tan, grey 13.0 106 orange SHALE, SILTSTONE, some fine grained SANDSTONE (slightly moist, Direct Shear moderately hard) - annd 0hpdding@311-.N20 WF22 0 NE ii Total depth 33'. No ground water, no caving. 5Ua-5Li ZCAC: DATA LogNo..... i...................... _...... Pearson - PROJECT: .................. ..................................................................................................................................................................................................................... Diamond Bar Tract No. 30578 Method of Drilling:.......2.4,, Bucket.-auger Logged by............MF..R............... Job No........ ................ Ground Elevation:.... 10U.t............. Location: ........................ See Mai...................................................Date 0bserved:J1 zV,61. DESCRIPTION SOIL TESTS 0 n g TOPSOIL: Brown sandy CLAY rT,,, rillIp 11 41 1 1 n T_moist-slightly moist, hard, porous) CL SUBSOIL - RESIDUAL SOIL: Red brown sandy CLAY 5 CL ppll 21.4 100 Silty'to sandy CLAY, red brown SM, moist, stiff) SM' Rg an silty fine/medium SAND dry -slightly moist, loose) P BEDROCK - PUENTE FORMATION: Tan fine/. medium grained SANDSTONE (slightly ML moist, slightly cemented) top 9-12' jointed, f$ulted - Approximate CLi III 6.4 115 rt•NF ota,21 Nr r+ r + Direct Shear- SHALE and SILTSTONE with Maximum Densi mounts of SANDSTONE with some AtterbergSMLiEnteddedmoist, hard) Bedding distorted Limits offset to 6" Mechanical Analysis ExpansionIDistortedbedding@15':N50 w,20-30 N Tan SANDSTONE (slightly moist, slightly Remolded emented ener Total depth 20'. No ground water, no caving. . I 5 5ULS-SUR ACE DATA LoglVo...... 5 ....... I ....................... PnoJ: CT:........Pearson - Diamond Bar - Tract No. 30578 Method of Drilllnp:.... 24, ....... RII1Ck.At77.d.l,ger................................topped by ............ E.R............... Job No....i6an3.0.1 ....................... Ground E:evation:.... 1147± ..............See Map..,...................................................Date Obzerved:_12/27Y68.... location:....., ........... O ` yi O`' c 0 fQ` tJa'2 Wi a DESCRIPTION /SOII. TESTS RESIDUAL SOIL: Silty SAND porous) moist, SM t BEDROCK - PUENTE FORMATION: Grey- ML+ white SANDSTONE slightly moist, slightly cemented to friable) 1illll! 8.7 101 Grey,' brown, orange, SILTSTONE and SHALE ( moist, moderately hard) Direct Shear d Bedding @ 6':N750W,5-70NE SM f i911f1f1 5.2 106 Buff -white SANDSTONE (slightly moist, x ? friable) ' Jointed locally loose. kk Joint @ 10':N100W,75-80oNE ii ML! P i! ID! 141.6 101 Interbedded SILTSTONE and SHALE with 7 minor amounts of thinly bedded SAND- STONE Bedding @ 16':N450W,140NE Bedding @ 18':N500W,140NE i Total depth 20'. 9 No ground water, no caving. p J O s I S;S,-;'u° ;:=Act A: ^ Log No.........6.......................... Pearson - Diamond BarPROJEC7:....................................................................................................................................................................................................................................... Tract No. 30578 Alothad of Drilling:.... .4., Bucket—auger.................................logged by ......... MER.................. Job No..... ....................... 1102t.......... location:'........................SeeGrounoElevation : ....................... Map .................................................... Date Observod:,12/27•(68- i Jc J OJ \v^ DESCRIPTION SO ]I TESTS TOPSOIL: Dark brown Silty CLAY moist to slightly moist with depth, stiff, porous) L Direct Shear 1 CSI1111I1 BEDROCK - PUENTE FORMATION: Grey SANDSTONE, fine grained Bedding @ 3' :N20. W, 29 NE a range, brown,SILTSTONE and SM grey SHALE with some caliche (moist, t fractured, moderately hard) Grey -white fine grained SANDSTONE wit ML UU1111 13.6 107 occasional thin siltstone bed Bedding @ 61,':N250W,240NE Interbedded grey, brown, tan, orange 1i SHALE and SILTSTONE with occasional thin SANDSTONE bed (slightly moist - moist, moderately hardb Bedding @ 12':N10°E,13 SE' Bedding @•19':N200W,100NE Total depth 21'. I No ground water, no caving. t R 1• SUB-SU RFACS DATA Loy............................... PROJECT:..............P'.arson - Diamond Bar Tract No. 30578 Method of Drilling: .... 2A........ ................................logged by ........ MF'..R................... Job No. ....... ..A-.101................. ". Ground Elevation:......1040.+...........location:..............................See Map..............................................Date Observed: l2/27/68 0'` o-ti a •a` s` 1 so- o q`o-s. Jr. DESCRIPTION SOIL TESTS CL TOPSOIL: Dark brown plastic CLAY Maximum moist -slightly moist, stiff, porous) Density ML Expansion to Remolded DirecFracturedSILTSTONEandSHALEwith CL caliche streaks - locally caliche Shear 5 IIIIU 25.2 98 replaces bedding.,. Mechanical. Analysis Bedding @ 4':N30oE110oNW Atterberg Limits SANDSTONE (hard, open fracturesV4ding@16':N20OW,13OSW sm 3.5 131 CLI CLAY and SHALE-SILTSTONE (moist, some slicks) SM Tan SANDSTONE (very hard) a• Stopped by hard sandstone @ 18'. I No ground water, no caving. 1 I I E 12 13 5J3-5L °F;C"_ I7ASA Log PRO'ECT:......,,Pearson - Diamond Bar -Tract No. 30578. Method of Drilling:.......2.4 Bucket —auger .............................Lofl}7ed by ........ P2k 2..................Job No........ .8.-3Q.1............... ._ Ground Elevation; ....... 1086±.......... Location: ........... See Mai ............................. .........................Dore Gbserved:_l2/27.(68.-, W J DESCRIPTION /SOIL TESTS TOPSOIL: Dark brown silty CLAY CL moist, cracked, porous, rootlets) 10.7 105 dBEDROCK — PUENTE FORMATION: Interbedd grey, brown, orange, white SHALE and CL 13..6 101 SILTSTONE with caliche streaks andi1111111IM01beds .(slightly moist, fractured, moderately hardy Bedding @ 4':N5 W,150gw Bedding @ 9':N55°E,21 NW S Orange brown limey SILTSTONE well cemented, some open fractures ML to 1/8") to Interbedded grey, brown SHALE and SILTSTONE (moist, hard tight) 9 Bedding @ 131:N150E,166NW i Near refusal @ 141. j No ground water, no caving. 1 1 I I Y SUS -SURFACE DATA Lao NO. ..... 9...................... PROJECT:.....Pearson - Diamond Bar - Tract No. 30578 Mothad of Drilling:.... 4" •Eucket—auger Logged b•............ MR Job o.....68.-...3..01 Ground Elevation: .................locariow.................See Map 12 28/68DatoObserved:..... 2 ,r O.0 T}V`LO'r 2, W\ DESCRIPTION $011 TESTS j J 0J n D I 1 1 1 I I TOPSOIL: Dark brown sandy CLAY CL T I RESIDUAL SOIL: Red brown sandy CLAY CL with some shale fragments. Ip Grey,•brown, buff SHALE and SILTSTONE ML! moist, fractured) Approximate beddin to, @ 8':N70°W,25°NE Yellow SANDSTONE (slightly moist, friable to slightly cemented) piljp 6.5 109 8-14': fissures, fractures open to td 3a" to ", locally broken up and ravels Grey, brown SILTSTONE and SHALE moist to.locally very moist, fractur(d fissures) 14h: 6" porous, very moist, soft SILT orange, very thin clayey seam @ base of SILT Attitude '@ 14h-15':N700W,35°NE CL IIIIIIII 27.8 93 18-191: very moist, porous, orange SILT, some irregular clay stringers d. startpd BEDROCK - PUENTE FORMATION: Tan to SM yellow SANDSTON9 and grey SILTSTONE ' interbeds (slightly moist -moist, tight -hard below 221) Contact 9 22': planer;•continuous N800W,23 NE Bedding @ 25':E-w,250N Bedding pinched out and distorted I below 27' in sand and shale, very 711111i1 I 24.2 96 tight t t I I Near refusal in sandstone Total depth 35'. J No ground water, no caving, slight i! ravelling in fractured sandstone 8-14 S ,.. '._+ -. -.. •', cam' . n 5:)"-5l9.rACr DA A LogNo ...... 1.0........................... 12 W7 4 PROJECT; ..... Pearson ... 7... Diamond..,Bar ....-... Tract ...No. ....30,578................................................................................................... 24" Eucket-auger................ .......Logged b.....MER......................Job No....68-301MethodofDrilling: .. ..................... ............................_. Ground Elovotion:....... 99.±.. See...r:1................................................... 12 28 ULocation : ........................... .........Date Observed:........1......,.......... 1 o p y 4, y y yn .,00` J7;. TQ`h,J, Off' yJdbv ' C bP O P y' J pJ eGO A DESCRIPTION SOIL TESTS Brown sandy SILT (moist to 11, MLE dry, porous below) E CLl Red brown sandy CLAY slightly moist, hard) t PUENTE FORMATION: White -light brown ML j silty fine SAND with shale and silt - to stone fragments SM slightly moist, disoriented shale 4.0 113 fragments) ll': Attitude on irregular shale bed thick, N-S,180W t Orange SANDSTONE (dry, friable, SM jointed,.roots) White fine/medium grained SANDSTONE 19': some open fissures and matted roots, bedding irregular 21': bedding slightly irregular,- SM some open fissures - N50W,70W 0111111 11.4 106 Predominantly buff, grey, brown ML SILTSTONE and SHALE to I CL f ; Yellow SANDSTONE l SMi t I• Contact:N200W,5°SW, some roots and 8E open fractures ML Interbedded.SILTSTONE and SANDSTONE to grey and orange SM Buff SANDSTONE with occasional shale SM; interbeds (slightly moist, friable to slightly cemented, some open fracture!) Continued @ 35'. ctca_s IR-ACrJVLJLJ :: ,V l. D.:t Yi PnOJcCL......Pearson - Diamond Bar - Tract No. 03578 Lco S\o....10... Cont.'........... Method a, Drdling:...... .4....... Bucket —auger ..................Logged by,AgR.....••.. ... lob No......6..&.-.3.DJ...................... Ground Elevction:.........943± 7............ Location: ......... O 2l Q>P>5>4 O > 3 See Map „ ......... Date Observed:•.12 28 68 DESCRIPTION SO1I TESTS S. 27. 88 Same as before Bedding @ 35' on slightly irregular SHALE bed, N350W,200NE y Clayey SHALE with SANDSTONE interbeds CL Bedding @ 381:N100W,50NE to Light brown SANDSTONE (slightly SM moist,, moderately hard) Predominantly'yellow SANDSTONE with S I I some grey SHALE and SILTSTONE inter-- beds. I Interbedded SILTSTONE, SHALE, SAND- STONE MLj to 19. 102 521: very moist clay zone about 4" CL thick with thin plastic grey cla @. base, continuous around hole N35 W 13 NE Interbedded grey SILTSTONE and SAND= STONE and dark grey brown SHALE less oxidized, harder and darker 52- 60') g Bedding @ 57':N-S,180E R s Total depth 60'. No ground water, no caving.. s 9 I u if I I Iit I. I 1 35- 1 SUB-5;jRFACE DATA too IN' I. PROJECT:....PearsonDiamond Bar Tract No. 30578 11 ........... ............... ................................. .. , . . ....................... Method of Drilling: .... 2A ...... .................................Logged by ........ ME .................. Job N . . ....6....8-........301............... I .............. Ground Elavation; .... ................ Location; ........................ nM ................................................... Data 40 Z, V%41 NV 41 13 DESCRIPTION SOIL TESTS RESIDUAL SOIL: Red brown sandy plastic CLAY (moist, hard) CL uuu2 1. 6 9 3 PUENTE FORMATION: Interbedded SHALE, SILTSTONE and SANDSTONE, grey, orange brown, buff (moist). lull[ 15.4 104 ML Distorted bedding, some open fracture to to 1/8" CL Approximate bedding @ 14': some disoriented shale fragments, N10 0 W,23 NE 26.71 94 White to auff silty fine/medium smi SANDSTONE Orange limey SILTSTONE (hard cemented MLI fragments but broken) hard on SW side of hole, orange moist, SILT on NE sid Bedding irregular 25-28''. Interbedded SANDSTONE, SILTSTONE and SMI 1111IJ 20.6 100 SHALE. Approximate bedding-@ 32': N-S,2.40 E in clay shale - Grey brown SHALE, MUDSTONE (moist,firr), ML to CL 37': Slicks and thinly bedded shale and siltstone, irregular digtorted Approximate bedding: E-W,22 S 39-40':Numerous sheared rock planes various d ;rect ons; most prominent sh ar plane N30 W,21 SW, plunge SW (downdip Continued @ 401. SUS -Su FACE DADA Log No:...-. 11 Cont". PROJECT: ................. r......... .i . , d,,,Bar - Tract.... o. 30578earsonDiamon Methodof Drilling; .......24...... logged b. 2................. Job Nc.....6.8.-3.01...... ............ ; Ground Elevation:....... 943±............ Locution .........................See......R................... Deto observed l2 ..6181..... I OTC i•..;. `QOyP J`F .W `,ia pWy J o w DESCRIPTION Soa TESTS SM to ML 12.0 123 ame as a ore 43': shear zone, no continuous planes bedding still distorted billllil 3.8 104 Merges to dark grey and brown SILT- STONE, and (slightly moist, to SHALE hard, brittle) SM Bedding @ 46':N50°W,18°SW Bedding @ 47':N45°W,.20°SW 1 Some moisture on fracture surfaces o Very hard drilling 50-521. Total depth 52'. Near refusal. No ground water, no caving. p 3 f 3 6 SUS-5U :+EE DAiA Log 110:...-12.... ................... . PROJECT: ........ Pearson - Diam p.ft...J sjgX...-....T.Zaat...NaV.-,..5,7.......................... ... ............. .... _..... Me -hod of Drilling: 2.....erBucket -au. ..........................logged b.....MER..................... Job No....b...-. Q1....................... b Ground Elevation; ....... 927.".. I......... Location...............See...Map Data 0bserved:..12/29/68.. ML SM ML SM 10 & a CL 411 3.8 105 DESCRIPTION vvLR: brown sanay siLar moist slightly moist, porous below) PUENTE FORMATION: Buff to yellow.sil fine/medium grained SANDSTONE slightly moist, friable to slightly Interbedded SILTSTONE and SHALE, some open fractures Interbedded SANDSTONE and SHALE, silty (fractured, ravelly to 10') distorted Same but tight, uniform bedding elow 10'. Yellow SANDSTONE,.fine/medium grained locally merges to white (dry, slightl moist, slightly cemented, tight Contact @ 12': good attitude.- unifor N-S,400E 20':Joint, open to 1/8"± N50oE,78oNW 20-25'':Joints offset occasional shale beds about 6" Same but orange, includes 6" broken lime SILTSTONE bed with.fracturesto , irreaulax bedding Channeling @ 35, with interbedded sandy SILTSTONE and SANDSTONE 35-40' irregular bedding with cross bedding 40+.:.Open fissure to"'N550E,750NW Continued @ 40'. SOIL TESTS 1 r•n'..:'• Cr:. ,y L'v :u 1,.1JJ/L.—.. ..C—J Log No...12.... Cont..'............ Person .Diamond Bgr Tract... No.cod06 78 M.ER....... PROD:CT:...........................................................................................,.........................,.....,........... Method of Drillin 24" Bucket -au er flJ y......• ................. Job No. ........ 6.8.r3.0.1................... 1 Ground Elevotion:....927+............•...Location:..................See..............Mp ......................................................... Date, 12 29 68Observed:...............1.......... a`' =` y P P \ \ Jc` p J O\v' 4 Al 5; z W, GI fit DESCRIPTION SO II TESTS Same as before Interbedded SILTSONE and-S fA'i1— Bedding @ 41':N-5,22°E SM to Primarily yellow SANDSTONE with fre- ML quent SHALE and SILTSTONE interbeds Approximate attitude on thin irregular CLAY bed @ 49':N100W,400E Grey SHALE and SILTSTONE with a few SANDSTONE interbeds, irregular, quite hard MIS 541: crushed SILTSTONE, fairly soft, moist, some slicked clay 55-561: 'sheared rock, shear plane @ 551, not continuous N600W,290SW 56': on slick surface N200W,250NE 591: on shear surface N15°E,50°SE Grey mudstone-shale stringers, irregu lar in yellow SANDSTONE MATRIX 1I SM 1111111 21.7 103 63' : Fault plane continuous round to holad then turns up nearly vertical Sc N75 E,50 NW, plunge of most striation is'down dip but some vary I depth 67'. Total I 1 i No ground water, no caving. r J SU--5 U ::A--E DAU.41 Lord No......13......_.................. PROJECT: Pearson - Diamond Bar - Tract No. 30578 I ......... ................ 1— ....... Method of Drilling;.....24 ....Bucket••-duggz..............................Logged by ...... .MER.................... Job No...6.a...3.0,1......................... 908+ See Ma 1 2 69GroundElevation:...............-................Location:...................................................p.............................................Date Observed:......... ti40o .P yi' 4• Jc J 0J w TOPSO DESCRIPTION SOIL TESTS IL: Brown -red brown silty CLAY CL; slightly moist -moist, porous) SM i PUENTE FORMATION: Interbedded and, mixed SANDSTONE and SHALE 4 SM It Buff silty fine grained SANDSTONE with scattered local shale interbeds Antithetic fault plane N-S,630W SMIlllll 3.9 102 Buff fine .grained SANDSTONE (dry, highly jointed, open fissures) Interbedded SILTSTONE and SHALE ML i slightly moist, crushed, fractured, distorted) Bedding @ 14':E-W,17°N on sheared SMq ( surface Bedding @ 17':N85 W,22 NMilI y Interbedded SANDSTONE, SILTSTONE and CLa SHALE in about 1' intervals of each 20-21': hard sandstone bed; continuou N850W,24°N Root @ 24' in chewed up material 3" thick with shear plane @ base Shear plane N500W,460NE Several faults in various orientation between 20-35' y 6" brown sandstone bed @ 321' 1 I 4 Fault attitude @ 351: sandstone on one side, clay -shale on other N350W,5 NE . I Continued @ 351. f 5?f5-5L .P.CCG D A"a Pearson - Diamond Bar - Tract No. 30578 aoJ:CT:.........................................................................................................................................................................:......................................._.................... Method a' Drilling: ... ,.24" Bucket -auger Lo red by ......... MR,.,,,,,•,,,,,.. -„Job Jo... 68-301,...................,. Ground :Icvction:.......9Ta±............. • .............See n2................................................ Date Observed:_1a/.6-9 -... Sy`Sa` J° 3 a e WO W O W OF bQWDESCRIPTION SOIL TESTS S OJ GO 2•• 2 O`er Same as before Thin slick plane -continuous @ 405', N500W, 110NE, parallels bedding below Well bedded, harder, less oxidized below gy 8.3 114 411: some micaceous beds, dark grey 111111below: 4'2' . i{ g Bedding @ 43':N800W,120NE S j Bedding @ 46-47':N600W,120NE a 4 MI II! 6.5 112 Total depth 501._ i' No ground -water, some ravelling and caving, in jointed sandstone 9-13'. I i I SUB-Su^r^.C_ DA.TA Log No...14............... _............. PROJECT: ............. Pearson - Diamond Bar - Tract No. 30578 24" Bucket -a ugerofDriilin.:........................ .g...............................Logged by ...... RIP' ........................ Job No.-U=1O........................... t Ground E!cvation:..•••$.....8.± See. Mai 1 2 69Location: Observed:....._.._ ....... DESCRIPTION SO n TESTS TOPSOIL: Dark brown sandy clayey SILT ML Tm-oist in upper few inches) ML Thin bedded SILTSTONE and SANDSTONE 5 SM affected by creep SM7 i E Bedding @ 7':N10 E,22 E Yellow brown SANDSTONE with siltstone interbeds (open fissures as much as 4" wide) . e ing with slicks Thinly interbedded SILTSTONE and ML SANDSTONE, a few open joints'as much as 4 inch wide SM° Bedding @ 19':N-S,29°E Crushed SANDSTONE and SILTSTONE Slick plane oriented N20°W,12oNE,' 1 SMI pods of clay gouge up to 1" thickE ML f I Greenish, gray SILTSTONE with thinly interbedded yellow -brown SANDSTONE; firm. j Bedding @ 31':N650W1100NE Slick plane oriented N500W,160NE withI 4 to k" of clay gouge, slicks down di parallel to bedding 39'':Slick plane oriented N45°W,18°NE aboe 1' sandstone bedv Continued @ 401,- ct ^UR"AC;_ n^n 14 Cont' 5-S. t : _ DATA Log E 3o..............I.......I................. PCOJEC7:........ Pearson Diamond Bar - Tract No. 30578 Method or Drilling:..2.4.11.....BUCkEt=4%je.K...................................Logged by ...... RZ........................ Job No. ..... 6.5.-au................. _... Ground Elevation:..... 8 ,,,,,,,,,,,,,See Ma 1 2 69location:...........,.,..............P..................................................Date Observed;........./.......__...- O LeC`c SY\ 2J?'ry ' \9`O'o\o \Q\,a' DESCRIPTION SOIL TESTS J° J eJ `o` . . 4 Same as before Thinly interbedded SILTSTONE, SAND- SM STONE and DIATOMACEOUS SHALE; firm, slighotly TTToist) Bedding:N50 W,17 NE @ 421. Fa 3I Total depth 471. 9 No ground water. J DAA7A Log No. ...... 15........... PROJECT: ......... Pearson....-..._Diamong.... Am ... . ..... .X.s1Ct...N4.r.....305.7.$.............................................................................................. Mothod of Drillin 24" Bucket -auger MER 68-301 g:.........................................................................................Logged by.....................................Job Na................I.............................. Ground c'Ievation: ..... 960.. ............... Location: ............ &Q.0..... MAD ............................................................... Dato Ob:orvod:..1ZZ/§_9 V \ tia O' f`0 f`f' 1J J` J pJ Co DESCRIPTION SOIL TESTS j i TOPSOIL: Dark brown sandy SILT MLIdrytol'; moist, porous below) CL SUBSOIL: Reddish brown sandy CLAY 4 I moist, very stiff) ME I 15.1 107 h S PUENTE FORMATION: Mixed up SANDSTONE SILTSTONE and SHALE, disoriented fragments ( moist, fairly soft to firm e with depth) SM 11117 10.7 106 10': orange limey SILTSTONE bed, locally very hard cementation, broken j n up with some fragments disoriented - open fissures to -Y" • 1I0 0 Approximate bedding @ 10':N50 E,40 SE MIIIIIII 17.4 95 1 Crushed, disoriented SILTSTONE gg i i Sli&k pl$ne - continuous M N50 W117 NE 17. 2 103 Grey to brown caly SHALE and SILTSTON with local thin fine SANDSTONE beds moist, very firm to hard) Att tudeeon slick planet N50W,17 NE, plunge:N10 W 25' on uniform bedding:N40W,16 a E 28' on uniform beddingcN42 W,17 NE'` I MI} 888 J1111111 2 2 . 1 103 E Total depth 31'. g No ground water, no caving. oa tio. 16 Pearson - Diamond Bar - Tract No. 30578PnOJECT................................................................................................................................................. ........................................... 24" E,ucket-auger MER 68-301Methodo,r 'Drilling:.........................................................................................logged by ...... ............................... Job ho...... ......................................... 858+ Location:.,................... eMa1/2/69 &Ground Elevation: ,,.,,......................p.....................................Dare Observed:... DESCRIPTION SOIL TESTS O` Ja ,> a oJe 4 `.r O`er+ CL I TOPSOIL: Dark brown plastic CLAY slightly moist, stiff) 1 i MLf BEDROCK - PUENTE FORMATION: Calcareous hard cemented) IISILTSTONE M? Ql11111 13. 9 98 Bedding almost horizontal ML tttttt Be ing @ 4 :N8 W,3 N I Interbedded yellow SANDSTONE and grey SILTSTONE (slightly moist-moist,firm) 6-15': f issure open locally to ;" N45W,85 SW 711l111 17. 4 102 9' : bedding N400E,110NW 9". sandstone bed @ 11-12' base:N60°E,8 NW Hole fairly tight, some small fissures Primarily grey to buff SILTSTONE and SHALE with local 6-9" SANDSTONE inter- ML II1111 18. 6 97 beds @ about 3' intervals and local thin SANDSTONE beds (slightly moist- moist, firm) 181: bedding N600E,70NW Ij ML full 19.0 96 211: bedding N650E,3-50NW to 23- 241: orange SILT with thin buff to SM a grey: SHALE and CLAY,beds (1/16) plasti J CLAY, slicked, sheared 1 @ 24' N35°E 10°NW Primarily buff to yellow SANDSTONE with occasional grey CLAY .SHALE interbeds 281: bedding with some.slicks N500Z 120NW M Illifl 25,5 6 Primarily grey CLAY SHALE and SILT - STONE -with SANDSTONE interbeds CL{ 307331: bedding slightly irregular nearly horizontal' 33'':N45 E14 NW ML? 9 39- 401: hard, orange limey SILTSTONE bed J J A Illll!! 18.0 113 continued j. 4 0 1 . n. 16 . PearsonROJcCi:.................................................................................................................................................................................................... Ciamond Bar - Tract No. 30578 Method of Drill: ng:............... 5mckS'.t.-.aujeX:....................... Logred b/......... M E.... I ............. Job No..... .................. Ground "clovarien:.... 8`.8± See MdP...........................................................DQ'OLocation:....... .............. Oh:Drvod:,la/.6 k i V'a a4Cay O\' J Ewa' Jva' OP Oa DESCFIMON /SO :1 TESTS CLl!I MLr II 9` E 4 I I Same as before 42': bedding N550E,100NW 42-43': hard limey SILTSTONE bed, some fractures 44': bedding with slicks N70°E,5°NW, trend of slicks N400E Primarily grey CLAY SHALE with somel II CL SILTSTONE and cross bedded SANDSTONE i ML 118 J 21.0 106 interbeds 49': bedding N20°o,12°IW 49': bedding N220 E, l NW SMi I 52: bedding N30 E,13 NW rV Total depth 55'. No ground.Water, no caving. F i f e 7 5Lu 5 U R F A-Ct DATA Log 1\0......:......I...................... PROJECT: ... ... Pea.......rson - Diamond Bar - Tract No. 30578 24" Bucket —auger A1Jthad of Jriliing:........................................._....................,.,........,,,....,,......Lorped by....M..........ER ....................... Job No. ..... 68-301 I....... Ground F, 1051± .Location :......................See Map .......Date Gb:orved:..la/§2 V\. DESMPTION SOIL TESTS TOPSOIL: Dark brown plastic CLAY CL slightly moist -moist, hard but slightly porous) CL Illllll 1 19. 5 100 PUENTE Fm.:.- Mzxe up SILTSTONE, CLAY, and SHALE with caliche streaks and pockets (dry) y PUENTE Fm.• Light brown, buff IML 6 SILTSTONE and SHALE with caliche pockets ( bedded but highly'fractured- 3 fissures fissures to ;", dry) Illlill 16.5 94 61: approximate bedding N150W,450SW Direct Shear 9- 101: open fissures to 35", bedding Consolidation 1 variable, fractured - fissures from 5- 15' generally trend N20 W, nearly i vertical jI 6 I Everything pretty broken up to 181. Thin sheared 136 1 ; I2 NWHard brown..SANDSTONE (cemented) a 011111 13.2 106 sin llasstic CLAY, same orientation I & Li nV ML BEDROCK - PUENTE FORMATION: Inter- bedded SILTSTONE and CLAY SHALE with local thin SANDSTONE beds (slightly moist- moist,'fi'rm, tight) 201: verythin CLAY, sheared N35°E ll NW MLI Orange limey SILTSTONE (cemented, I. very hard) Light. grey to white SANDSTONE with local thin SHALE interbeds (slightly moist, very hard) 27': thin sheared ISMsICLAYbuttightaboveandbel2Total depth 30'. No ground water, no caving. j Hole fractured with open fissures to 181. Tight with bedding continuous llfaroundhole18-30': 5 LJS JL.I r'i'A C'E DAY A Pearson - Diamond Bar - Tract No. 30578 Lod vo....... 18. 24 Bucket -auger E Jay .o,....,6,8.-.3.9. Method of Drilling: ................................................g......................................Logrcd by.............P.4B.3......,..... ..................... Ground @Iovation:......... 1015±......... Location; ..................See...MaP................................................. ....Date ob:erved:..h13Z*6.9.......... O DESCRIPTION SOIL TESTS U CLI 9 TOPSOIL: Dark brown plastic CLAY moist, stiff) R ML Light brown to tan SILTSTONE and SHAL with SOIL pockets to 4' and caliche a stringers and pockets and beds to 7' dry -slightly moist, locally cemented porous) S Light brown to grey SILTSTONE and ML SHALE with local thin SANDSTONE beds fractured, dry) 12' open.fissures - bedding @ 12': NIS5aE,26°NW 4 to 6" SANDSTONE bed @ 12'. 3 r I Brown to'buff SANDSTONE (fairly hard, cemented blocks with open fractures SM( between) ML. SILTSTONE and SHALE brown SANDSTONE (moderately hard MLp cementation, some fractures) S CL y ppp111111 27.6 90 Consolidation Light brown to grey SILTSTONE and SHALE' (pretty well fractured, dry) 20,-21': fissure trend up and down hole @ about N70 E - nearly vertical tt offset f Same but tight below 21' Approximate bedding @ 21':N40°E,15°NW 21,21i: 6" diatomaceous shale bed, ha d- siliceous cementation - continuous 1 Stria CL 9111111 S d 20.8 87 221: very thin cl$y, sheared, paralle bedding (N400E,15 NW) 23;': bedding N35°E,9°NW - continuous around hole o 0 25': bedding N35 E,12 NW - continuous s Consolidation 1 14 around hole f j Interbedded SANDSTONE and CLAY SHAL slighter moist, firm-tight)31':N30'E,12°NW 3 InterbeddedSM CL i i SANDSTONE (cemented, very hard SANDSTONE and CLAY SHALE slightly moist, hard) 35': bedding N40°E,9°NW u Total depth 40'. No,ground'water, np cav nq Fractured to 211 t:;rrht hcJnw D` X III _ I EIGHTON and ASSOCIATES INCORPORATED SOILENGINEERING TESTING GEOLOGY October 6, 1978 ENGINEEpiNG GE 5ECTIO i ENVIRONMENTAL SCIENCES Project No. 678146-02 TO: Mr. Vincent Szeto 1625 Old Mill Road San Marino, California 91108 SUBJECT: Geotechnical Grading Plan Review of Lot 182, Tract 30578, Diamond Bar, County of Los Angeles, California Reference: Geologic Review Sheet, Lot 182, Tract 30578, 2503 Razzak Circle, Diamond Bar, California; County of Los Angeles Department of County Engineer, dated September 26, 1978 Introduction As requested by you, we have reviewed.the 40-scale grading plan prepared for the development of Lot 182, Tract 30578, Diamond Bar, California. This plan review is based upon previous reports prepared by Robert Store and Associates, Inc., and our geotechnical review of Lot 182. dated March,17,•1978. For -pur- poses of this report, additional data was obtained in the field. The data is presented on a printed copy of the Grading Plan prepared by Larry Jack 'Wood, Architect, Claremont, California. The Grading Plan is dated September 18, 1978. Accompanying Maps and Appendix Index Map - Page 2 Geotechnical Map (40-scale) Appendix A - General Grading 1 I Plate I and Earthwork Specifications 1 7265 JURUPA AVENUE, SUITE 8, RIVERSIDE, CALIFORNIA92504 714)7860156 (714)698.3848 IRVINE 6 WESTLAKE/VENTURA • REDWOOD CITY • DIAMOND BAR/WALNUT •SAN BE RNA RDINO/RIVERSIDE- SAN DIEGO 678146-02 l • .J r u' Ya S L E.I9• xa '1a „i p f e•, f . d6 yTT(( T of • : ;.". 6 ` 2f ' =: Yz =_ T 2•• 'L ``TJe ' . °Poi 40 e •'ems • '.o F tr EP-' Y '~ ° E e • '1 • T 's•` .I Zvi 'd• a ^" . E + a i .+ " : o '• ^ .• ••.•..+ '• T•`. 3 x of ' P. •Ti o 3 wy •af '+ y a,J gy • '• '°'°`' e, i I 1 i . Ve •+ 1. 4 ' ri ti•~' t u M1" 200'" 0 zoo 400 60o $Do ro0o 1200 kale -feet INDEX MAP OF . LOT 182, TRACT 30578 DIAMOND BAR, COUNTY OF LOS ANGELEScA • •[ow90 nxc. xv9 Iavmivx IaR xn-•ua Subject Lot Shown In Yellow) 1 2- LEIGHTON and ASSOCIATES INCORPORATED Ij$ i 1 678146-02 t Proposed Grading Proposed grading will be limited to the northeasterly portion of the lot. A south -facing cut slope which is designed at 2:1 or flatter with a height t of 12± feet will be developed along the northeasterly portion of the site. A building pad will be constructed resulting in a 2:1 fill slope that ranges in height to as much as 8± feet. tGeologic Conditions Additional geologic mapping was conducted by us along a cut slope present on adjacent Lot 183 (see Plate I)., Bedding attitudes taken along the slope show that rock units across the proposed building site should be inclined slightly east of north as previously reported. Those indicated orientations should be favorably oriented with respect to the proposed cut and fill grading for building site development. 1 1 1 1 1 3 _ I u LJLJ LEIGHTON and ASSOCIATESmconaoanYeo 678146-02 CONCLUSIONS AND RECOMMENDATIONS Conclusions Based upon our geotechnical review of the grading plan of Lot 182, we are of the opinion that the site can be satisfactorily developed as designed. How- ever, the recommendations presented in our report dated March 17, 1978 and those discussed below should be incorporated during site development. tRecommendations Cut Slopes Cut slopes should be geologically inspected during grading to confirm antici- pated geological conditions. If the proposed slopes are found to be poten- tially unstable, a buttress will have to be designed and constructed for slope stabilization. 1 Fill Slopes A minimum equipment width sidehill fill key should be provided for the north portion of the proposed fill slope (placed on natural ground steeper than 5:1) descending from the building pad. The key excavation should be inspected during grading to verify geologic conditions along the natural slope. Inspection and Testing 1. All grading should.be performed in accordance with the County of Los Angeles requirements and our General Grading and Earthwork Specifications see Appendix A). 2. Geologic inspections should be conducted as necessary to verify whether the anticipated geologic conditions do exist. 3. Construction inspection should be performed by the soil engineer during the following stages of grading: A. Upon completion of clearing and during excavations. B. During all rough grading operations including removals of unsuitable tmaterials, recompaction, benching and filling operations. 4. All footing excavations should be inspected by a soil engineer and engi- neering geologist prior to placement of forms or steel. Presaturation of slab subgrade should be tested by a soil engineer. 4 _ I ILILJ LEIGHTON and ASSOCIATESIN40APORATED 678146-02 1 1 1 1 1 5. A final report and as -built geologic map should be prepared after comple- tion of rough grading. FK/lvs Distribution. (4) Addressee Joh fully submi ted, n F. Hoefferle Engineering Geologist EG 799 10 S. A. Siddiqui RICE 19915 LEIGHTON and ASSOCIATES INCORPORATED I 1 1 1 1 1 H 1 1 1 i 1 1 1 1 1 1 1 1 APPENDIX A lf'T;Ift LEIGHTON and ASSOCIATESINCOPVOPAIEO 6%814b-DY APPENDIX A GENERAL GRADING AND EARTHWORK SPECIFICATIONS Scope a) This section contains general specifications for work relating to the following construction: Site Clearing and Grubbing Preparation of Subgrade in Areas to be Filled Placement of Fill Subdrains Trench Backfill b) The owner shall employ a qualified soil engineer to inspect and test the fill as placed to verify the uniformity of compaction to the specified density requirement. The soil engineer shall advise the owner and grading contractor immediately if any unsatisfactory soil related conditions exist and shall have the authority to reject the compacted fill ground until such time as corrective measures necessary are taken to comply with the specifications. It shall be the sole responsibility of the grading contractor to achieve the specified degree of compaction. 2. Clearing, Grubbing and Preparing Areas to be Filled a) All brush, vegetation, rubbish and desiccated top clay soil shall be removed, piled, or otherwise disposed of so as to leave the areas to be filled free of vegetation, debris and desiccated top clay soil. Any soft and swampy spots in the canyon areas shall be corrected by draining or by removal of the unsuitable materials. b) The natural. ground which is determined to be satisfactory for the support of the filled ground shall then be plowed or scarified to a depth of at least six inches (6") and until the surface is free from ruts, hummocks, or other uneven features which would tend to prevent uniform compaction by the equipment to be used. The scarified ground should be compacted to at least 90 percent of the maximum laboratory density. Where undisturbed bedrock is exposed at the surface, scarification and recompaction may not be required. c) Where fills are made on hillsides or exposed slope areas, the existing top unstable materials "should be removed. If existing slopes are steeper than 5 horizontal to 1 vertical, horizontal benches shall be cut into firm and competent undistrubed soil or bedrock in order to provide both lateral and vertical stability. d) All areas -to receive controlled fill, including all removal areas and toe -of -fill benches, shall be inspected and approved by the soil engineer and/or engineering geologist prior to placing con- trolled compacted fill. 21;*g A-i LEIGHTON and ASSOCIATES i NCORPORAfCO 3. Fill Materials and Special Requirements The fill soils shall consist of select materials approved by the project soil engineer or his representative. These materials may be obtained from the excavation areas and any other approved sources, and by blending soils from one or more sources. The material used shall be free from organic vegetable matter and other deleterious substances, and shall not contain rocks or lumps of greater than eight inches in diameter within a distance of ten feet from any finished compacted surface. If excessive vegetation, rocks, or soil with inadequate strength or other unacceptable physical characteristics are encountered, these shall be disposed of. During grading operation, if potential problem soils are found, these soils shall be tested to determine their physical characteristics. Any special treatment recommended shall become an addendum to these specifi- cations. Boulders greater than eight inches but less than or equal to two feet in diameter should be uniformly distributed in the compacted fill areas but no closer than ten feet from final grade and should be surrounded with sufficient amounts of compacted finer -grained materials. No nesting will be permitted. Boulders greater than two feet in diameter shall be placed in approved disposal areas no closer than ten feet from final grade and shall be placed in windrows in such a manner that voids will not exist around boulders. Continuous inspection by.the project soil engineer is required during rock disposal operations. Placing, Spreading and Compacting Fill t•iaterials a) The suitable fill material. shall be placed in approximately level layers which, when compacted, shall not exceed six inches (69. each layer shall be spread evenly and shall be thoroughly mixed during the spreading to insure uniformity oftmaterial and moisture in each layer. b) When the moisture content of the fill material is below that specified by the soil engineer, water shall be added until the moisture content is near optimum as specified by the soil engineer to assure thorough bonding during the compacting process. c) When the moisture content of the fill material is above that specified by the soil engineer, the fill material shall be aerated by blending and scarifying orc.other satisfactory methods until the moisture content is near optimum as specified by the soil engineer. d) After each layer has been placed, mixed, and spread evenly, it shall be thoroughly compacted to not less than 90 percent of maximum density in accordance with ASTM D1557-70 (five layers). Compaction shall he accomplished with sheepsfoot rollers, multiple wheel pneumatic -tired rollers or other approved types of compaction equipment. Rollers shall be of such design that they will. be able to compact the fill material to the specified density. e) Special mixing and watering effort may be required where diatomaceous materials are encountered to achieve the recommended moisture content and density. 1 o. A-ii I u ILILJ LEIGHTON and ASSOCIATES INCORMRNTCO f) Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compacting of the slopes shall be accom- plished by backrolling the slopes in increments of three to five feet in elevation gain.or by other methods producing satisfactory ' results. Relative compaction shall be at least 90 percent to the finished slope face. g) The soil engineer and/or his designated representative shall observe the placement of fill and shall take sufficient tests to provide an opinion on the uniformity and degree of compaction being obtained. 5. Trench Backfills a) Trench excavations for utility pipes shall be backfilled under engineering supervision. b) After the utility pipe has been laid, the space under and around the pipe shall be.backfilled with clean sand or approved granular soil to a depth of at least one foot over the top of the pipe. The sand backfill shall be uniformly jetted into place before the controlled backfill is placed over the sand. c) The onsite materials, or other soils.approved by the soil engineer, shall be watered and mixed as necessary prior to placement in lifts over the sand backfill. d) The controlled backfill shall be compacted to at least 90 percent of the maximum laboratory density as determined by the ASTM compaction method described above. e) Field density tests and inspection of the backfill procedures shall be made by the soil engineer during backfilling to see that proper moisture content and uniform compaction is being maintained. The contractor shall provide test holes and exploratory pits as required by the soil engineer to enable sampling and testing. A-iii I o LEIGHTON and ASSOCIATES NCOF>ONATEO I I t BENCHING DETAIL TOE OF SLOPE SHOWN ON GRADING PLAN VARIABLE FILL f PE HEIGHT PROJECTED TOP OF FILL SLOPE I:I MIN. FILL - - - J i NATURAL - I SLOPE - P=E ptER 1 - 4'TYP. 6zNCH UNSU\4IIGHTl ( VA RIE9 15 T Y P. ---- + BENCH WIDTH i r 2'MIN DOWNSLOPEKEY DEPTH 15' M IN J SASE KEY WIDTH INCLINED 2%D MIN. INTO SLOPE) I n nnp s A- . v ILJIJ LEIGHTON and ASSOCIATES INCORPORATED TYPICAL, BUTTRESS SECTIONS General Buttress Fill Section 4" diameter outlet pipes at 100' horizontal intervals 201 max. typ. i 1' Clr. j- 19 V1 20 VA Benching mi nF— 30" comuacted fill blanket as needed Subdrain - See "Buttress Subdrain Detail" b = 1 max D and W DETERMINED BY DESIGN Small Buttress Section 4" diameter outlet pipe at 100' horizontal intervals max = 20 ft. / 1' clr L1- I L 12' 30" compacted fill blanket as needed Benching Subdrain - See "Buttress Subdrain Detail" LEIGHTON and ASSOCIATES INCOPPORAlfD TYPICAL SUBDRAIN DETAILS FOR SIDEHILL FILLS $ BUTTRESS FILLS compacted fill 4" min. osolid outlet pipespacedaat100'lioritontal Min..3ft3 per lin.f intervals. Filter Material METHOD B 4 min. approved A perforated pipe perforations down) minimum 2% gradient to outlet. radijent A Bench inclined toward drain Min. 12" cover oved solid outlet pipe Typical benching 112" llin DETAIL A -A Filter material to meet following specification or approved equal: Sieve Size Percentage Passing 1................ 105 3/ 4............... 90-100 3/ 8 ............... 40-100 No. 4.............2S-40 No. 8.............18-33 No. 30............ $-IS No. SO............ 0-7 No. 200........... 0-3 D. - - Temporary fiil level Compacted backfill 6" in. select bedding backfill Approved Pine. Tunes: i. Schedule 40 Poly -Vinyl - Chloride 2. Corrugated Metal Pipe 14 9,1. 6" AC dipped 3.- Aluminum Corrugated Pipe 1000 psi AC dipped 4. Acrylonitrile Rutadinennc Styrene Schedule 40, 900 psi u I • A-V1 LEIGHTON and ASSOCIATES iNCOPVORPTEO e URBAN GEOLOGY / D SEISMICITY GRADING CONSULTANT ENGINEERING GEOLOGIST Phone (113) 883-5169 July 26, 1977 Project #77176 TO: Gordon Builders, Inc. ,el 1130-F North Kraemer Anaheim, CA 92806 Ib Attention: Mr. Gordon J. Pivonka i FROM: C. Michael Scullin SUBJECT: Engineering Geological Evaluation Lot 183, Tract 30578 2505 Steeplechase Lane The Country in Diamond Bar County of. Los Angeles, California SCOPE In accordance with your request, an angineering geologic study and evaluation of the subject property has been conducted to determine geologic safety for the proposed single family residence. An areal geologic site location map has been included with this report. The map is a reproduction of a portion of the geologic map within the U.S.G.S. Professional Paper 420-B, "Geology and Oil Resources of the Eastern Puente Hills Area, Southern California", 1964. ENGINEERING GEQLQ UGO1 SECTION 6422 TONY AVENUE • CANOGA PARK, CALIFORNIA 91307 Page 2 July.26, 1977 Project #77176 This investigation was based upon: 1. Geologic field reconnaissance and detailed mapping conducted July 25, 1977. 2. Review of pertinent reports and geologic maps of the adjacent areas prepared by this office and others. 3. Review of "Final As -Graded Geologic Report, Rough Grading Completed, Tract 30578, Diamond Bar, California", Robert Stone and Associates, Inc., November 5, 1970, 1-68-301-09. 4. Review of "Soil Engineering Report on Compaction Testing, Tract 30578, lots 1 through 188, Diamond Bar," Robert Stone & Associates, Inc., November 5, 1970, 1-68=301-10. 5. Review of Grading Plan prepared by S. W. Bradford & Assoc. of Placentia at a scale of 1"=30', undated. ACCOMPANYING ILLUSTRATIONS Area Geologic Location Map Seismic Index Map Page 5 Page 10 Table I - Maximum Probable Earthquake Page 11 Table II - Seismic Parameters Table III - Earthquake Recurrance Intervals Site Geologic Map Cross -Section A -A' PRINCIPALS Owner: Gordon Builders, Inc. 1130-F North Kraemer Anaheim, CA 92806 714) 524-0177 Page 3 July.26, 1977 Project #77176 Page 12 Page 13 Appendix Appendix Soil Engineer: Hanunond Soil Engineering 199 N. State College Orange, CA 92668 Phone (714) 634-4801 Engineering C. Michael Scullin, EG 170 Geologist: 6522 Tony Avenue Canoga Park, CA 91307 Phone (213) 883-5269 PROPOSED DEVELOPMENT Acreage: Number of Lots: Type of Development: Adjoining the Site: Existing Condition of Site: Sewage Disposal: Gross area - 1.2+ acres One parcel Single family residence N'ly - range & Razzak Circle S'ly - range & Steeple Chase Lane E'ly - intersection - Steeple Chase & Razzak W'ly - range Range and heavy gras's and trees Sanitary Sewers Access to Development: Steeplechase Lane to Razzak Circle PHYSIOGRAPHIC SETTING Geomorphic Province: Landform: Topographic Relief: Maximum Relief of Site: Average Natural Slope: Maximum.Thickness of Fill: Thickness of Topsoil: Colluvium Drainage: Rainfall: Climate:, Vegetation: Intiltration: Erosion Hazard: Page 4 July.26, 1977 Project #77176 Peninsular Ranges Head of a ravine Highest: 853'+ Lowest: 8101+ 43'+ 2:1 to 5:1 None 6".to 3' - average of 1'' 3' to 5' W'ly down the side slope 16"+ mean annual during 29 year base period; 1933-1962 Mediterranean Rye grasses, wild flowers, trees Low Moderate r N %\X l n\ \ t 7\ @ /ram" ` 7l' j• l/ r iz ('r 11. 57 \ ,.i JJf I: Ix za XV v v Nl 2421.;,spc. 22.- Al 752 ------ Ul 7 k "I if-, Vii .':_4 1> 24 60 k, Pm 7'0' 1"0 0, 5;/ 16; It IZ 12NS X16 -A PS 1 T6131 17 k 13 2/20;, -4- 4 1. . ..... 2 r%lU2la 29 0' 4 It 2- 4 S7- 3 Sol 4 05 30 40 7...: LT ENGINEERING GEOLOGY GENERAL SETTING Page 6 July 26, 1977 Project #77176 The subject site is located at the head of a westerly trending ravine or canyon easterly and above Brea Canyon. The site drainage is contributary to the Brea Canyon water- shed. The site is within the northerly foothills of the Eastern Puente Hills, situated within Diamond Bar. The subject site is undeveloped range land containing mostly trees and tall grasses. No structures within the site as yet. EARTH MATERIALS The subject site is underlain by a thin soil mantle, Colluvium (Col) and the La Vida member of the Puente Formation (Tpl) of Miocene age. TOPSOIL A thin veneer of topsoil, 6 inches to three feet thick, averaging one and one half feet, mantles the site. The top- soil is a brown, clayey silty sand and clayey silt (adobe). It is generally moist and firm. The topsoil appears to be slightly expansive. Page 7 July 26, 1977 Project #77176 COLLUVIUM (Col) The topsoil grades into colluvium of three to five feet thickness. The colluvium is composed of dark to light brown I sand clay and clayey silt, moist and tight. Ityyyyg appears to have expansive characteristics. BEDROCK (TPO The entire site is underlain by the Puente Formation of Miocene age. The bedrock on this site contains siltstone, thin bedded shale and medium grained sandstone, yellow brown to buff colored, soft and well bedded. The rock types correlate with the LaVida member of the Puente Formation. They are generally moist, dense and well bedded. GEOLOGIC STRUCTURE The site is located within the Diamond Bar Anticline. Bedding planes are consistently to the north and northeast throughout the site. Bedding planes have a general near east -west to N30W trend and a north -northeasterly dip of 80 to 251 within the site area. It appears that the Diamond Bar Anticlinal axis may pass through the proposed 2:1 cut slope within the site. Bedding planes are anticipated to dip favorably into the proposed cut slopes on the site. Page 8 July 26, 1977 Project #77176 SEISMICITY Historical records of earthquakes indicated very minor seismic activity within the immediate area of the site. Several earthquakes of a magnitude less than 3.9 have been recorded with adjacent areas. Only one of these minor earthquakes was strong enough to be noticed by residents of the area. The Seismic Index Map of Los Angeles Basin shows epicenters for earthquakes greater than 4.0 magnitude, occurring between 1934 and'March 1973. Many of these, depending on their distance, were large enough to be felt at the subject site. The Whittier Fault is known to displace late Pleistocene deposits of the general Puente Hills -Whittier area which in places might be as young as 10,000 years of even younger. However, it has nowhere been observed to disrupt the recent alluvium of the present drainage system. The preponderance of geological evidence would seem to indicate that the Whittier Fault was most active during the last Miocene and Pliocene epochs, and that it has probably not been as active since the late Pleistocene. Recent survey investigations with sensitive seismic instruments have indicated that the Whittier Fault is exhibiting some (Microseismic) activity at depth. The general conclusion is that the Whittier Fault should be Page 9 July.26, 1977 Project #77176 considered potentially "active", however, it is relatively inactive as far as significant earthquakes are concerned. The most probably major earthquake sources of significance for the subject site are the San Andreas fault zone located about 27 miles to the northeast and the Sierra Madre and San Jacinto fault zones which lie 8 miles and 23 miles to the north and northeast, respectively. These faults will most likely be associated with future moderate to major earthquakes and are considered the controlling faults relative to the seismic design of the subject site. (See Table I for their Maximum Probable Earthquake Parameters). The Norwalk Fault, because of its tentative nature, and the Whittier Fault, because of its apparent relative inactivity as far as significant earthquakes) are not considered as important in terms of earthquake generating potential, and therefore, are not classified as controlling faults. The acceleration of 0.44g noted in Table I is a peak ground acceleration anticipated during a magnitude 7.0 earthquake 8 miles from the site. The repeatable high ground acceleration used for design purposes would average 65% of the (peak) 1. acceleration. Therefore, the 0.44g may be reduced 35% for design purposes. 1 f}1r d ( sh ( \v C. In v " \ I1 i f It `x1r : i:1 c — age 0 .o' 0 r 1' , TW(% 1 ^ I t oojeC #77F76 PA I YJ GOB y If /i./ i HnOJ 1 \ O to.\\ { C, i2 W O W, 1 Ir T /i Ili ' 0 ,•c--I lL l 1••1 O N N O goo 41 2 ear .•__ I n n i O .'1. / I . j ? — Zi l `• r. Q. J t \ ,\ N\` 1 aci lz All Luji. o L / u < /n 'v1 vl JCLI LO V1. J'!•.-.. 1 ' yam IGi !On COO ram'O G ri M © CO i MN WEiH z toO'd omv O M pg O i Nn Dm UCO ZA b d o O o., fj H O O I 1 1 O o WPWi N ccq MaO w 0 0 0 zO k H OM' N N O O O 0 z ho 1 I 1 t 0 N cl N N 0 q O O O O W N 0 in L'I q n n H t 1 I 1 O to 0 O q t\ n 0 Oi W W NN n q Cl) c'1 d., N N N EH-+ Hd N rn A d V W Sr L N td O to D a o u N 1 oN UN ti co o 0 4.) 4 H q 71 C Z d d ci H Cd a) O vi [4 W O t=, cn C=, 2 H 44 Page 11 Ply 269 1977 Project ` 77176 m m 2 m 3 8)w o 9 m to 0 mm 0 x to 2 2 m r 14 w w w bf Qw x\. Qn OD Q)= e/ 1 x— Q/ CD to w w Id: w A ocl 2 j c E 4 r A UV 2 9:In= s RJAJ eavqa IwgSS 2=1.31;s Ok21o5I&oa a vRC man Page 12 July 25, a 97.7 aPro ect 1177 S( j 0 bb CD W . LO4)® 2± t w « 0 zz w& E/® In Cs 7 kd\ k5/ 3 4 G E . 2\ cs N u tb re In +J ro o ro J w w 1 H O N uU00 G Cvv 4 4 O y fa :< T 14 00 v v _ to 41 e-•t r-1 ro o w WW 1 G O H u U GV •.d G OUGL D sJ ro7 U LJ 0 ro 0 Co 0 0 0 0 1 1 t 0 Co Co IT o 0o M 0 0 0 0 0 r-1 r•1 ON 1 1 1 cn O O t O N E o O co O N xO O O O O O N O O N D Rf. 0 O. O V O O t a N O O O r4 O O ra M w 0 0 r4 D. I { 0 0 0 0 o In cn x 00 OO% O o O M M 0o O ri r--1 t 1' O N N O O O O O %D cn TO O O (D D N O O O cr) n oo Page 13 N N July 26,.1977 0 o Project. "77176 0 0 0 co co o 0 0 0 0 In o b " 1 1 lI O O O . O O U O r•1 Ux 0 0 o O k ON r-1 O O O N O M rl N C G" O O O 0 O O Co c0 41) . . It to h co r'1 U rl ra iJ NO y T TQ O O O n•) N O O O O O r-1 raCL x rup G W E x v o In N rn lonN vMi rn co O. d C7 O N co O O e-i ro E c7 O O O O O O v 1-1 G O r-1 fJ 5. lb w-1 d fn W tll U ra 1.1 1 4.+ ro ro cn m L C y C .-•i 1 to ro to O iJ rl j d 4i 1.1 r•t 41'. 1J L U ro W 1 o o v o ro w k. ro k' aGi a aGi H H m D 1 H o S+ ro 1I W U G W to ro ro uui N Gi 3a G y v O tll i7 U 61 d O Page 14 July 26, 1977 Project #77176 1. FAVORABLE ENGINEERING GEOLOGIC CONDITIONS 1. No gross landslides nor surficial slumps present on the site. 2. No major or active faults transect the property. 3. Groundwater problems are not in evidence nor anticipated. 4. Liquefaction, ground lurching and differential compaction hazard potential is considered low in the subject site areas. 5. Bedding planes dip favorably into proposed cut slopes. 6. Earth materials can be readily excavated with modern earthmoving equipment. UNFAVORABLE ENGINEERING GEOLOGICAL CONDITIONS 1. Thick colluvial soils will probably exist in the area of the proposed toe of fill. 1. Expected ground shaking from possible future earthquakes Page 15 July 26, 1977 Project #77176 are summarized in Table I. The structural design should consider the following seismic parameters: Acceleration Period Duration 0.44g 0.32 seconds 30 seconds The repeatable high ground acceleration used for design purposes would average 65% of the 0.44g (peak) acceleration. 2. Bedrock dips favorably into the slope. Cross-sectionA-A' is enclosed to show the subsurface conditions. 3. The building pad drainage should be directed to and dispersed into the drainage course. 4. A brow ditch drain is not considered necessary at the top of cut slope due to the minimum of 15' to 50' of con - tributary watershed above the cut. Razzak Circle diverts the major watershed away from the site. 5. Foundation design should be recommended by the Soil Engineer. 6. Toe of fill key should be excavated 2' into bedrock.'' Topsoil and colluvium should be removed from.areas to receive fill or be tested and approved by the Soil Engineer. Page 16 July.26, 1977 Project #77176 FINAL CONCLUSION The subject site is considered geologically favorable for residential development. We appreciate being of service to you. If you have any questions, please do not hesitate to call. Respectfully submitted, C. MICHAEL SCULLIN Engineering Geologist, EG 170 xc: (6) Gordon Builders, Inc. 1) File Encl: Site Geologic Map (Based upon the Stone Geological Map with additional Structural Attitudes) Cross -Section A -A' 4?C'. S LEIGHTON and ASSOCIATES 0INEERIN6 CEOLC3 i EC T ION 17975 Sky Park Circle, Suite H, Irvine, California 92714 March 17, 1978 TO: Mr. Vincent Szeto 1625 Old Mill Road San Marino, California 91108 ENGINEERING, GEOLOGY ENVIRONMENTAL SCIENCES, RESEARCI AND GEOTECHNICAL PLANNING SUBJECT: Geotechnical Review of Lot 182, Tract 30578, Diamond Bar, County of Los Angeles, California Introduction Tel:(714)556.1421 556.1422 Project No. 278146-01 t As requested by you, we have reviewed the geotechnical conditions pertaining to residential construction on the above described property. Our review is based upon previous reports covering the area during tract grading, a site reconnaissance and preparation of this report. Robert Stone and Associates, Inc., were the geologists and soil engineers during tract development. Although no site plan or grading plan is available at this time, we understand minor grading is anticipated to provide a building area on the lot. Accompanying Maps, Illustration and Appendix Index Map - Page 2 Geotechnical Map - (40-scale) - Plate I Geologic Cross -Section A -A' - Plate II Appendix A- Referenced Reports &_ q1 N E E R 1 N G GEOLOGY ISECT10N AVG 3 11978 1 1 11 1 1 1 1 I 1 e. i iA. d' / scale feet INDEX MAP PREPARED .. OF 111. REARED. . .,°c,.. LOT 182suoceiEOuioE^Dsoi , TRACT 30578 DIAMOND BAR,_COUNTY OF LOS ANGELES Subject Lot Shown in Yellow) 2 - Leighton & Associates 278146-01 Site Conditions Lot 1.82 extends down a westerly -sloping nose of a ridge near Diamond Bar Boulevard. Except for street improvements (Razzak Circle) provided for access to the top of the lot, the property is in a natural condition with no Restricted Use Areas., Natural slope gradients down the lot range from 5:1 or flatter near the top to 3:1 or flatter near the bottom. A municipal sewer system is provided for the tract and onsite sewage dis- posal will not be required. echnical Conditions Geology According to previous mapping performed on and near the subject lot, bedded rock units in the area are inclined slightly east of the north (see Geotech- nical Map). Local variations occur along the north flank of the ridge east of Lot 182, however, they do not appear to affect the integrity of the sub- ject lot (see Referenced Report 1). Earth Materials According to Referenced Report 2, surficial soils exposed on the lot consist of sandy clays which are expected to exhibit swell characteristics of 9.50 percent under a surcharge load of 60 psf. Topsoils are expected to be on the order of approximately two to three feet thick. No data relative to expan- siveness of the bedrock units for the lot are presented in that report. How- ever, based upon our previous experience in the area, bedrock units are expected to be moderately to highly expansive. 3 - Leighton & Associates II 278146-01 I I 1 1 1 1 1 I CONCLUSIONS AND RECOMMENDATIONS fnnr lnci nnc 1. Based upon our review of the pertinent available data relating to Lot 182, we are of the opinion that the site can be satisfactorily developed for residential purposes providing the recommendations discussed below are in- corporated for lot improvement. Our recommendations are premised on the possibility that minor site grading will be required for adequate drainage and proposed building construction. 2. If grading is required for site development, the grading plan may have to be reviewed and verified by signatures of a qualified engineering geologist and soil engineer according to Los Angeles County requirements. 3. Components of northeasterly inclined bedding are expected to be neutral or inclined slightly into natural slopes. Natural slopes should be stable. Recommendations 1. Cut Slopes: Cut slopes -should -be graded at inclinations of 1.5:1 or flatter.. Any proposed north -facing cut slopes should be avoided as they will pro- bably expose daylighted bedding components in underlying bedrock units. This should not present any design complications since south -facing slope development would appear to be most likely for. level building pad construc- tion. 2. Fill Slopes: Any proposed fill slopes should be designed at inclinations of 2:1 or flatter. Stability analyses will be required for slopes steeper than 2:1. Based on the data available to us, there are no restrictions as to location for fill slopes on the site from a geotechnical standpoint. 3. Retaining Walls: Any proposed walls retaining compacted free draining level earth should be designed for an equivalent fluid pressure of 30._pcf. A passive pressure value of_300-pcf-equivalent fluid pressure and coeffi- cient of friction of 0.4 is recommended for design. - 4 - t I Leighton & Associates 278146-01 The drainage for retaining walls should consist of a perforated four -inch diameter plastic pipe embedded in at least three cubic feet. of gravel per t lineal foot. 4. Foundation Design: Based on our engineering review and considering medium to high expansion potential of the soils, the following general recommenda- tions should be considered for design and construction. Expansion charac- teristics of the soils exposed at final grades should, however, be verified upon completion of grading. a. Continuous interior and exterior footings tied to each other should extend a minimum of 18 inches into _compacted fill and/or through inches firmanytopsoilandthenaminimumof18into Puente Forma- tion (bedrock). Any pier foundations should extend to equivalent depths. At this depth, the footings and piers can be designed for a bearing_pressure of 1500_p5f. b. Any footing excavations proposed for construction on slopes should be stepped according to standard procedures. c. The footings should be reinforced with a minimum of two No. 4 bars at the top and two at the bottom. d. Slabs -on -grade should be a minimum of 3-5/8-inches thick and rein- forced with minimum 6x6-6/6WWF placed in the center of the slab. The slabs should be provided with 6-mil visqueen properly protected with sand. e. The subgrade beneath the slabs should be presoaked to a depth of at least 18 inches to minimum 90 percent saturation. S. Drainage: 1 a. Subdrains should be constructed for any proposed retaining walls. 5 Leighton & Associates 278146-01 11 1 1 I 1 1 1 1 1 1 b. Surface drainage should be directed away from foundations and slopes toward the street or approved drainage devices. 6. Inspection and Testing: a. All grading should be performed in accordance with County of Los An- geles requirements. b. Geologic inspections should be conducted periodically and as necessary if grading is required. c. Construction inspection should be performed by the soil engineer during the following stages of grading: 1. Upon completion of clearing and during excavations. 2. During all rough grading operations including removals of unsuitable materials, recompaction, benching and filling oper- ations. d. All footing excavations should be inspected by a soil engineer and engineering geologist prior to placement of forms or steel. Pre - saturation of slab subgrade should be tested by a soil engineer. e. A final report and as -built geologic map should be prepared after completion of rough grading. R ectfully submi ted, John F. Hoefferle Engineering Geologist EG 799 S: A. Siddiqui RCE 19915 ja Distribution: (4) Addressee - 6 - Leighton & Associates I 278146-01 1 t 1 I 1 I APPENDIX A REFERENCED REPORTS Leighton & Associates j 278146-01 1 I APPENDIX A REFERENCED REPORTS 1. Robert Stone and Associates, Inc., 1970, Final As -Graded Geologic Report, r Rough Grading Completed, Tract 30578, Diamond Bar, California, dated November 5, 1970. 2. Robert Stone and Associates, Inc., 1970, Soil Engineering Report on Com- paction Testing, Tract 30578, Lots 1 through 188 and Tract 30289, Lots 6 through 8, Diamond Bar, County of Los Angeles, dated November 5, 1970, 1 1 1 1 1 A-i Leighton & Associates Sth ANX! Wq- 4A ANN AV140 40- AW Al/ VR% PERU Aofl 1 1 1 1 1 EN,glNEERING GE0,4JGSECTION .::._,u_Y_; MR. VINCENT SZETO Geotechnical Report of Rough Grading Lot 182, Tract 30578 Diamond Bar,,County of Los Angeles, California Project No. 678146-03 T! II • I ag LEIGHTON and ASSOCIATES INCORGORPTED I • III II a (/ December 4, 1978 TO: Mr. Vincent Szeto 1625 Old Mill Road San Marino, California 91108 1NEER N ENVIRONMENTAL SCIENCES Project No. 678146-03 SUBJECT: Geotechnical Report of Rough Grading, Lot 182, Tract 30578, Diamond Bar, County of Los Angeles, California REFERENCE: Geotechnical Grading Plan Review of Lot 182, Tract 30578, Diamond Bar, County of Los Angeles, California Leighton and Associates, dated October 6, 1978 Introduction This report has been prepared to summarize the geotechnical conditions of grading performed to develop Lot 182 of Tract 30578 and to present our recommendations for proposed residential construction. The subject lot and t geotechnical data gathered during grading is shown on the accolrlpanying 40-scale Geotechnical Map. The base map was prepared by you. Accompanying Maps and Appendix Index Map - Page 2 Geotechnical Map (40-scale) - In Pocket Appendix A - Laboratory Test Data and Summary of Field Density Tests 7265 JURUPA AVENUE, SUITE 8, RIVERSIDE, CALIFORNIA 92504 1714) 785.0156,• (714) 888-3848 IRVINE • WESTLAKE/VENTURA • REDWOOD CITY • DIAMOND BAR/WALNUT. SAN BERNARDINO/RIVERSIDE • SAN DIEGO 1 1 t 1 1 1 1 1 rC L` it OfJ r P•iJ r ^ . so f•'—•— 1. J 1 SJD D SOD .DD 6V !CD i000 ISDD scale feet INDEY. MAP OF LOT 182, TRACT 30578 DIAMOND BAR, COUNTY OF LOS ANGELESunsann :m sehut, Subject Lot Snown In Yellow) 2- I I I • LEIGHTON and ASSOCIATESINCORPORATED 678146-03 SummaU of Geotechnical Conditions 1. Areas to receive fill were cleared of all significant vegetation and deleterious material was removed as recommended. 2. Rough grading was performed in accordance with the As -Built Grading Flan prepared by you. Recommendations included in our referenced report were followed during rough grading. 3. A southwest facing cut slope inclined at 2:1 or flatter with a height of 12± feet was constructed along the easterly portion of.the lot. Geologic mapping of the cut slope is shown on the Geotechnical Map. 4. A 2:1 south and west facing fill slope was constructed along the westerly side of the building pad. The maximum height of this fill slope is on the order of 28 feet. A key approximately.15 feet wide and extending 2 to 3 feet into the under- lying bedrock was excavated for the fill slope. Benching into bedrock was maintained during fill placement. Estimated limits of the key are shown on the accompanying As -Built Geotechnical Map. Minor fill grading was also performed to support the driveway leading from the existing Razzak Circle as shown the map. on 5. The cut portion of the proposed building area was overexcavated to a depth of at least 30 inches and replaced as compacted fill. This was intended for uniform foundation support for the proposed structure. 6. The compaction standard used for the minimum requirements was 90 percent of ASTM Test Method D 1557-70. Results of the tests are attached as Appendix A. The estimated locations of the tests are shown on the accompanying Geotechnical Map. 11 I 1 1 I n nnu3 - u ILJLJ • LEIGHTON and ASSOCIATES INCORPORATED 678146-03 CONCLUSIONS AND RECOMMENDATIONS Conclusions 1. Geotechnical conditions encountered during rough grading were, in general, as previously anticipated. 2. Cut and fill slopes were graded at 2:1 (or flatter) and are considered stable. All graded slopes should require planting with approved ground cover as soon as practical. Irrigation of slopes should also require careful control to minimize overwatering and saturation. 3. The pad for Lot 182 is considered suitable for the construction of a single-family residential structure. Based upon inspection, the foundation soils should be moderately to highly expansive. Recommendation included in our previous reports should be followed during construction. These are repeated as follows. Recommendations 1. Foundation Design A. Continuous interior and exterior footings tied to each other should extend a minimum of 18 inches into compacted fill and/or through any topsoil and then a minimum of 18 inches into firm bedrock. At this depth, the footings can be designed for a bearing pressure of 1500 psf. 1 B. The footings should be reinforced with a minimum of two No. 4 bars at the top and two at the bottom. C. Slabs -on -grade should be a minimum of 3-5/8 inches thick and rein- forced with minimum 6x6-6/6 WWF placed in the center of the slab. The slabs should be provided with 6-mil visqueen properly protected with sand. D. The subgrade beneath the slabs should be presoaked to a depth of at tleast 18 inches to minimum 90 percent saturation. 2. Drainage 1 Surface drainage should be directed and maintained away from the slopes and structures toward approved drainage devices. I nn 4- u I• LEIGHTON and ASSOCIATESINCORPORATED 1 678146-03 1 3. Inspection and Testing All footing excavations should be inspected by a soil engineer prior to placement of forms or steel. Presoaking of slab subgrade should also be tested by a soil engineer. i t sb Distribution: (4) Addressee 1 1 1 1 1 1 Respectfully submitted, John F. Hoefferle Engineering Geologist EG 799 S. A. Siddiqui RCE 19915 5- I ILJu • LEIGHTON and ASSOCIATES INEOPPOHPTEO I I, I 1 1 i 1 1 1 1 h 1 1 1 1 1 1 1 1 I 1 APPENDIX A PT;ft LEIGHTON and ASSOCIATES INCORPORATED Project No! 678146-03 Plate No: A-i 331A (9/77) Leighton & Associates 1 SUMMARY OF FIELD DENSITY TESTS Project No. 678146-03 Tract No.:30578,Lot 182 Test No. Test Dote Test Location Soil Type Comments TestnElev. Dry Dens., pcf Moisture, % Relative CompactionFieldMaximumFieldOpt. 1 11-17 A 810 97.4 104 17.2 17 94 2 A 812 98.4 104 18.9 17 95 3 B 849 104.2 111.5 16.0 16.7 93 4 C 815 93.4 100 23.2 20 . 93 5 C 818 92.7 100 25.1 20 93 6 11-20 C 822 92.6 100 20.5 20 93 7 A Retestby8 86. 9 104 18.3 17 84 8 b A Rete825of 7 95.7 104 18.7 17 92 9 s- B 828 100.8 111.5 16.8 16.7 90 v ar10 11-21 B 831 100.7 111.5 17.2 16.7 90 11 11-27 A 837 100.2 104 18 17 96 12 C 838 93.0 100 21 20 93 13 A 839 98.3 104 19 20 94 14 11-28 C 839; 90.6 100 18 20 90 Field density tests were performed in accordance with ASTM D1556-64 Denotes Driven Sampler Method of Testing, ASTM 02937-71 Maximum densities and optimum moistures were determined in accordance with ASTM D1557-70 Form 202A (8/77) A-ii 1 0 A ........:.. .... 5 COUNTY OF LOS ANGELES DEPARTMENT OF COUNTY ENGINEER BUILDING ANTSAFETY DIVISION SUPERVISED GRADING INSPECTION VERIFICATION To be filed.in duplicate at the local Building and Safety Office) Job Address or Tract No. Lot 182, Tract 30578 Locality Diamond Bar permit No. W/.Y _ Owner Mr. Vincent Szeto Contractor Walter White ROUGH GRADING VERIFICATION 1BY SOILS ENGINEER FEA) I verify that the earth fills placed on the following lots were installed upon competent and properly prepared base material and compacted under my supervision in compliance with requiremer of Building Code Section 7010. 1 further verify that where the report or reports of an engineer geologist, relative to this site, have recommended the installation of buttress fills or similar . stabilization measures, such earthwork construction has been completed in accordance with the approved design. Fill slope surfaces have been compacted in accordance with my recommendations. Sub - drains have been provided where required. LOT NOS. 182 See report dated 121 for compaction test data, recommended allowable soil bearing values and other specia r-1ecommendations. FXPANSIVE SOILSZZ(NO) LOT NOS. 182 BUTTRESS FILLS (YES) ((NO OT NOS. __182 Remarks: Engineer _ C_J / tOr e CiL i(GL. neg. No. 19915 Date 12/05/78 Signature) BY SUPERVISING GRADING ENGINEER B) I verify that rough grading of the lots listed below has been completed under my supervision and in conformance with plans therefor marked "APPROVED" by the County of Los Angeles. The work verified as correct includes: grading to approximate final elevations; staking or property lines; location and gradient of cut and fill slopes; location, cross -sectional configuration and flow - line gradient of drainage swales and terraces (graded ready for paving); berms installed where indicated; and required drainage slopes provided on building pads. LOT NOS. Complete one of -the -following: As - built plans have been prepared 1. Latest plan revision date oOu. % 131k County approval date OThere have been no changes in design subsequent to permit issuance. Remarks: Engineer Reg. No. I &0 Date 12 t FIP ll GRADING VERIFICATION (Signatur C) I verify to the satisfactory completion of grading in accordance with the approved plans. All required drainage devices have been installed; slope planting established and irrigation systems provided ( where required); adequate provisions have been made for drainage of surface waters from each building site; and included herewith, if required, is evidence of an effective rodent control program, LOT NOS. Remarks: Engineer Reg. No. Date Signature) DEPARTI•: ENT USE ONLY: Tract No. Permit No. Date Report approved by: Title _ Date Items approved: A - Lot Ambers B - Lot N:ambers G - Lot Numbera 5oits Report Dated Approved by _ Date Remarks: SGR- 00414/75 Revised t i i.. , cV R`1n,nS T.;.y.71nG.•nanv—al i I ENGINEERING 66N t SECTION SEP 14 1982 tRETAINING WALLS DESIGN RECOMMENDATIONS PROBED STORAGE ROOM ALONG SLOPE AT THE REAR OF EXISTING RESIDENCE; L-OT—T7 TRACT 30578 (22225 STEEPLECHASE LANE DIAMOND BAR, LOS ANGELES COUNTY September 8, 1982 Project No. 6820414-02 1 Prepared for: David Lee Landscape Company, Inc. 538 Somerset Drive Placentia, California 92670 Attention: Mr. David Lee I LEIGHTON and ASSOCIATES INCORPORATED U O 1 SOIL ENGINEERING TESTING GEOLOGY ENVIRONMENTAL SCIENCES September 8, 1982 Project No. 6820414-02 TO: David Lee Landscape Company, Inc. 538 Somerset Drive Placentia, California 92670 ATTENTION: Mr. David Lee SUBJECT: Retaining Walls Design Recommendations, Proposed Storage Room Along Slope at the Rear of Existing Residence, Lot 173, Tract 30578 (22225 Steeplechase Lane) Diamond Bar, Los Angeles County Introduction As authorized by you, this report presents the retaining wall design recommendations 1 for the subject storage.room construction. The room will be constructed by excavating into the fill slope above the concrete ramp, descending from the rear of the house, to the lower area on the lot. We understand the proposed room will be located very near or along Section A -A', just above the "Post -Graded Ramp", as shown in our re- view report dated July 26, 1982. The maximum height of the retaining walls will be on the order of nine feet. Accompanying Map and Appendix Index Map - Page 2 Appendix A - References Utilized 7265 JURUPA AVE., SUITE C, RIVERSIDE, CALIFORNIA 92504 (714) 785-0156 IRVINE . WESTLAKE/VENTURA . DIAMOND BARIWALNUT . SAN BERNAROINO/RIVERSIDE . SAN DIEGO 0 PALM DESERT v 1*eajr r N • ryf. i wry f' O ! +../, N fC. 1 N e • a s c' _ . S. 1. b H b - •_ mob k / ! • ry w Y -'•• ry .\ t, ' '/-' Cry. IS 61 rl`o•GC o J ^I BBp J S• _01M1H wf ••U O_ b ' A N \1. w .f N ry i. w ` • \ ` ` pia y - o • w \ 111 r; _ 200 0 200 400 600 600 1000 1200 scale feet LOT 173, TRACT 30578 DIAMOND BAR, COUNTY -OF LOS ANGELES Subject Lot Shown in"Yellow) InV.w(0 fY C. L IC+q OY ! /JJOCUC<S III ]I ]II-ISp-.110 C-. N W Z_ [!T;ft LEIGHTON and ASSOCIATES INCORPORATED 1 6820414-02 IRECOMMENDATIONS Wall Design 1 Based on our review of the previous reports by Robert Stone and Associates, the following recommendations can be considered in design and construction of walls retaining free draining level backfill. 1. Active Pressure: 45 psf EFP 2. Passive Pressure: 350 psf EFP 3. Coefficient of Friction between Soil -Concrete Foundation: 0.35 4. Soil Bearing: 1500 psf Minimum 18 inches embedment of footings into compacted fill Drainage The drainage behind the retaining walls should consist of a perforated four inch diameter pipe. The pipe should be wrapped in Mirafi 140 filter fabric and em- bedded in at least 3 cubic foot of gravel per lineal foot. Inspections and Testing r1 footing excavations and.retaining wall cut should be inspected by Leighton and sociatespriortoplacement of_steel. Backfill of the retaining wall should be mpacted to at least 90.perc6nt per the maximum dry density determined by ASTM D1557-78, and should be verified by the soil engineer. Respectfully submitted, o John F. Hoefferle Engineering Geologist EG 799 / S. A. Siddiqui RICE 19915 Distribution: (3) Addressee 1) Reagan & Kramer, Structural Engineers Attention: Mr. Chris Hansen t & 3 — LEIGHTON and ASSOCIATES INCORPORATED APPENDIX A LEIGHTON and ASSOCIATES INCORPORATED 1 6820414-02 APPENDIX A REFERENCES UTILIZED Leighton and Associates, 1982, Geotechnical Review, Proposed Rear Yard Improvements, Lot 173, Tract 30578, 22225 Steeplechase Lane, Diamond Bar, County of Los Angeles, California, dated July 26, 1982 (Project No. 6820414-01). Robert Stone and Associates, 1970, As -Graded Cross -Sections, Diamond Bar Tract No. 30578, dated January 9, 1970 (Job No. 1-68-301-02Z).- 1970, Final As -Graded Geologic Report, Rough Grading Completed, Tract 30578, Diamond Bar, California, dated November 5, 1970 (Job No. 1-68-301-09). 1970, Soil Engineering Report on Compaction Testing, Tract 30578, Lots 1 through 188, and Tract 30289, Lots 6 through 8, Diamond Bar, County of Los Angeles, California, dated November 5, 1970 (Job No. 1-68-301-10). 1 0 ITIM gip• LEIGHTON and ASSOCIATES INCORPORATED Tip. \ `, •/pGluui`Illll 1 i I ENGINEERING GE040 SECTION GEOTECHNICAL REVIEW;k 2 PROPOSED REAR YARD IMPROVEMENTS 9 19 1 LOT 173, TRACT 30578, 22225 STEEPLECHASE LANE, DIAMOND -BAR, COUNTY OF LOS ANGELES, CALIFORNIA 1 - July 26, 1982 Project No. 6820414-01 Prepared For: DAVID LEE LANDSCAPE COMPANY, INC. 538 Somerset Drive Placentia, California 92670 ATTENTION: Mr. David Lee ENVIRONMENTAL SCIENCES July 26, 1982 Project No. 6820414-01 TO: David Lee Landscape Company, Inc. 538 Somerset Drive Placentia, California 92670 ATTENTION: Mr. David Lee SUBJECT: Geotechnical Review, Proposed Rear Yard Improvements, Lot 173, Tract 30578, 22225 Steeplechase Lane, Diamond Bar, County of Los Angeles, California Introduction As authorized by you, we have reviewed the geotechnical conditions relating to back yard improvements proposed for the subject property. Our review is based upon the as -graded site conditions as reported by Robert Stone and Associates in 1970. The back yard site improvement plans (5 sheets) were prepared by Michael Ray Pool and Yards Concepts, and bear a date of June 1982. Accompanying Maps, Illustration and Appendices Index Map (200-.scale)- Pa e 2 Geotechnical Map (40-scale - In Pocket Cross -Section A -A' (20-scale) - In Pocket Appendix A - General Earthwork and Grading Specifications Appendix B - References Utilized 74304 HIGHWAY Ill, PALM DESERT, CALIFORNIA 92260 714) 568 1338 IRVINE • WESTLAKE/VENTVRA • DIAMOND BAR/WALNVT 6 SAN RERNARDINO/RIVERSIDE • SAN DIEGO • PALM DESERT obZU414-U1 Qo l 1 i'' •'4 / 200 O 200 400 600 800 1000 1200 scole feet LOT 173, TRACT 30578 DIAMOND BAR, COUNTY -OF LOS ANGELES. Subject Lot Shown in Yellow) 1 unto e1 Y. 1. [wt0/ / A$SO[li[[J rDy W •[DO+DD +U[n +La4 Ixr]I ]xl•09 ILY 3iEdxia LEIGHTON and ASSOCIATES INCORt'ORATED 6820414-01 SUMMARY OF FINDINGS 1 1. Summary of Graded Site Conditions Based upon our review of grading reports, the approximate upper half (south half) of.Lot 173 was developed into a split-level area during mass grading of Tract 30578. The remaining lower half (north half) remains in a natural condition. A satisfactory building site was provided on the graded upper level portion facing Steeplechase Lane. The graded lower level portion of the lot (approx- imately 13 feet below) and the remaining natural portion of the lot farther north are included as part of a Restricted Use Area. The restricted use consists of areas of extensive remedial grading performed in landslides to provide stabilized residential construction sites. Restricted use also encompasses natural areas composed of contiguous landslides which are unaffected by building construction. The graded lower level portion of Lot 173 was developed during the construction of a shear key to support upper level portions of the lot. The remaining down - slope portion of Lot 173, farther north, exists as a landslide (see Section A -A'). 2. Summary of.Site Conditions t Since the time of tract grading, a concrete ramp was developed along the fill slope descending from the rear of the house to the lower level area. The history of this ramp is not known to us. The graded lower level portion of the lot is presently utilized as a horse corral . tAn approximate 25 foot high side lot fill slope descends from the west side of the lower level portion of the lot. The slope is inclined at approximately 1-1/2 horizontal to 1 vertical, and was developed in conjunction with the shear key graded for the lot (see Plate 1). Drainage across the lower graded portion of the lot is directed to the west I/ and over the 1-1/2:1 side lot fill slope. Some serious erosion has occurred along the top of the slope. The rear of the lower level portion of the lot appears to consist of fill whereas it was apparently natural upon the completion of tract grading. The trunks of oak trees have been covered with spoil, and rodent holes are prevalent indicating loose earth materials. 3. Proposed Development The graded lower level portion of the lot is proposed for yard improvements in the form of a recreation area. It is our understanding no improvements are considered for natural portions of the lot. n n u LJLJ • LEIGHTON and ASSOCIATES INCORPORATED 1 6820414-01 1 According to the plans provided for us, improvements will consist of con- structing a swimming pool, a spa, a concrete sp_or--t court, and a teahouse with a w2 doencateahouseanddeckwillbesituatedastridethetop ofthe approximate 25-foot high 1-1/2:1 west -facing side lot fill slope. The construction layout and elevation plan indicate grade ductions for the recreation area on the order of 30 inches increases and re- and 18.inches, respectively. We assume "zero" grade is intended at the northwest corner of the pool and is considered existing grade -bench grade. See Sheet 3, t Construction Layout and Elevation Plan). Block walls and wrought iron fencing will be used to enclose the improvements. We understand that the pool walls have been designed considering expansive soil conditions. Drainage across the designed recreation area appears to be directed toward the top of the 25± foot high side lot fill slope. . 1 4_ n&n I u IuLJ• LEIGHTON and ASSOCIATES INCORPORATED 6820414-01 CONCLUSIONS AND RECOMMENDATIONS tConclusions 1. Based upon our review of data relative to site grading, we are of the opinion that the development of the backyard area f6r recreational purposes is feasible as proposed. 2. Indicated removals of existing earthwork for pool, spa, and site development are not significant with respect to the intended use of the underlying shear key. 3. Most excavations are expected to be achieved in existing fill. The sport court and perimeter wall will be -situated on transition cut and fill, some of the latter of which could be uncompacted., The tea house is also expected to be situated on transition cut and fill. 4. Previous data (by Robert Stone and Associates) suggests that the fills should have medium expansion potential.(4.9 percent expansion under surcharge of 60 psf). 1 Recommendations 1. All of the proposed recreational facilities should be constructed on compacted fill, and according to our General Earthwork and Grading Specifications pre- sented in Appendix A. 2. Drainage over man-made slopes should be.prohibited. Approved drainage devices should be utilized to.drain.site runoff. 3. To provide a uniform compacted fill mat for the sport court and wall, the area including the court area and -extending three feet outside the wall should be undercut a minimum of 24 inches. The material should then be replaced as compacted fill. 4. Eroded areas.of the fill slope should be repaired prior .to construction of the.' teahouse and appurtenant deck. Downslope foundations for both facilities should be embedded such that a horizontal distance of at.least five feet is obtained from the face of the slope to the outside edge of the foundation. 5. The concrete court slab should be a minimum four inches thick and provided with 6-6/6x6 mesh reinforcement. Four inches of gravel base is advisable below the slabs. The use of low slump concrete is recommended. 6. All site preparation and fill placement should be inspected and/or tested by, y Leighton and Associates. All footing excavations should also be inspected .- prior to placing building materials in the excavations. A final report may be prepared subsequent to work completion. 5 - TT;0% LEIGHTON and ASSOCIATES INCORPORATED 6820414-01 It has been a pleasure to work with you on this project. If you have any questions, please do not hesitate to call. Respectfully submitted, John F. Hoefferle Engineering Geologist EG 799 C.. S i j/ RCE 19915 JH/SAS/ja Distribution: (6) Addressee 6- a I u luu• LEIGHTON and ASSOCIATES INCORPORATED I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 APPENDIX A 1E LEIGHTON and ASSOCIATES INCORPORATED 6820414-01 APPENDIX A GENERAL EARTHWORK AND GRADING SPECIFICATIONS 1.0 General Intent These specifications present general procedures and requirements for grading and earthwork as shown on the approved grading plans, including preparation of areas to be filled, placement of fill, installation of subdrains, and excavations. The recommendations contained in the geotechnical report are a part of the earthwork and grading specifications and shall supersede the provisions contained hereinafter in the case of conflict. Evaluations performed by the consultant during the course of grading may result in new recommendations which could supersede these specifications or the recommendations of the geotechnical report. 2.0 Earthwork Observation and Testin Prior to the commencement of grading, a qualified geotechnical consultant (soils engineer and engineering geologist, and their representatives) shall be employed for the purpose of observing earthwork procedures and testing the fills for conformance with the recommendations of the geotechnical report and these specifications. It will be necessary that the consultant provide adequate testing and observation so that he may determine that the work wos accomplished as specified. It shall be the responsibility of the contractor to assist the consultant and keep him apprised of work schedules and changes so that he may schedule his personnel accordingly. It shall be the sole responsibility of the contractor to provide adequate equipment and methods to accomplish the work in accordance with applicable grading codes or agency ordinances, these specifications and the approved grading plans. If, in the opinion of the consultant, unsatisfactory conditions, such as questionable soil, poor moisture condition, inadequate compaction, adverse weather, etc., are resulting in a quality of work less than required in these specifications, the consultant will be empowered to reject the work and recommend that construction be stopped until the conditions are rectified. Maximum dry density tests used to determine the degree of compaction will be performed in accordance with the American Society for Testing and Materials test method ASTM D1557-78. 3.0 Preparation of Areas to be Filled 3.1 Clearing and Grubbing: All brush, vegetation and debris shall be removed or piled and otherwise disposed of. 3.2 Processing: The existing ground. which is determined to be satisfactory for support of fill shall be scarified to a minimum depth of 6 inches. Existing ground which is not satisfactory shall be overexcavated as specified in the following section. Scarification shall continue until the soils are broken down and free of large clay lumps or clods and until the working surface is reasonably uniform and free of uneven features which would inhibit uniform compaction. 1 A-, 6820414-01 3.3 Overexcovation: Soft, dry, spongy, highly fractured or otherwise unsuitable ground, extending to such a depth that surface processing cannot be adequately improve the condition, shall be overexcavoted down to firm ground, approved by the consultant. 3.4 Moisture Conditioning: Overexcavated and processed soils shall be watered, dried -back, blended, and/or mixed, as required to attain a uniform moisture content near optimum. 3.5 Recompaction: Overexcavated and processed soils which have been properly mixed and moisture -conditioned shall be recompacted to a minimum relative compaction of 90 percent. 3.6 Benching: Where fills are to be placed on ground with slopes steeper than 5:1 horizontal to vertical units), the ground shall be stepped or benched. The lowest bench shall be a minimum of 15 feet wide, shall be at least 2 feet deep, shall expose firm material, and shall be approved by the consultant. Other benches shall be excavated in firm material for a minimum width of 4 feet. Ground sloping flatter than 5:1 shall be benched or otherwise overexcavoted when considered necessary by the consultant. 3.7 Approval: All areas to receive fill, including processed areas, removal areas and toe -of -fill benches shall be approved by, the consultant prior to fill placement. 4.0 Fill Material 4.1 General: Material to be placed as fill shall be free of organic matter and other deleterious substances, and shall be approved by the consultant. Soils of poor gradation, expansion, or strength characteristics shall be placed in areas designated by the consultant or shall be mixed with other soils to serve as satisfactory fill material. 4.2 Oversize: Oversize material defined as rock, or other irreducible material with a maximum dimension greater than 12 inches, shall not be buried or placed in fills, unless the location, materials, and disposal methods are specifically approved by the consultant. Oversize disposal operations shall be such that nesting of oversize material does not occur, and such that the oversize material is completely surrounded by compacted or densified fill. Oversize material shall not be placed within 10 feet vertically of finish grade or within the range of future utilities or underground construction, unless specifically approved by the consultant. 4.3 Import If importing of fill material is required for grading, the import material shall meet the requirernents of Section 4.1. 5.0 Fill Placement and Compaction 5.1 Fill Lifts: Approved fill material shall be placed in areas prepared to receive fill in near -horizontal layers not exceeding 6 inches in compacted thickness. The consultant may approve thicker lifts if testing indicates the grading procedures are such that adequate compaction is being achieved with lifts of greater thickness. Each layer shall be spread evenly and shall be thoroughly mixed during spreading to attain uniformity of material and moisture in each layer. A-ii 6820414-01 5.2 Fill Moisture: Fill layers at a moisture content less than optimum shall be watered and mixed, and wet fill layers shall be aerated by scarification or shall be blended with drier material. Moisture -conditioning and mixing of fill layers shall continue until the fill material is at a uniform moisture content at or near optimum. 5.3 Compaction of Fill: After each layer has been evenly spread, moisture - conditioned, and mixed, it shall be uniformly compacted to not less than 90 percent of maximum dry density. Compaction equipment shall be adequately sized and shall be either specifically designed for soil compaction or of proven reliability, to efficiently achieve the specified degree of compaction. 5.4 Fill Slopes: Compacting of slopes shall be accomplished, in addition to normal compacting procedures, by backrolling of slopes with sheepsfoot rollers at frequent increments of 2 to 3 feet in fill elevation gain, or by other methods producing satisfactory results. At the completion of grading, the relative compaction of the slope out to the slope face shall be at least 90 percent. 5:5 Compaction Testing: Field tests to check the fill moisture and degree of compaction will be performed by the consultant. The location and frequency of tests shall be at the consultant's discretion: In general, the tests will be taken at do interval not exceeding 2 feet in vertical rise and/or 1,000 cubic yards of embankment. 6.0 Subdrain Installation Subdrain systems, if required, shall be installed in approved ground to conform to the approximate alignment and details shown on the plans or herein. The subdrain location or materials shall not be changed or modified without the approval of the consultant. The consultant, however, may recommend and upon approval, direct changes in Subdrain line, grade or material. All subdrains should be surveyed for line and grade after installation and sufficient time shall be allowed for the surveys, prior to commencement of filling over the subdrains. 7.0 Excavation Excavations and cut slopes will be examined during grading. If directed by the consultant, further excavation or overexcovation and refilling of cut areas shall be performed, and/or remedial grading of cut slopes shall be performed. Where fill - over -cut slopes are to be graded, unless otherwise approved, the cut portion of the slope shall be made and approved by the consultant prior to placement of materials for construction of the fill portion of the slope. A-iii 6820414-01 TRANSITION LOT DETAILS CUT -FILL LOT f NATURAL GROUND 5_ MIN, 1 r-------__ COMPACTED --FILL__ =' P RAP — _===— cc ' 30_MIN. 1_=_UNSV Sp__ _ —_— __ OVEREXCAVATE AND RECOMPACT RE _— ---- UNWEATHERED BEDROCK OR MATERIAL APPROVED BY THE GEOTECHNICAL CONSULTANT CUT LOT NATURALGROUND i i REMOVE-.-- UNSUITABLE 5' MATERIAL MIN-. 30" MIN. COMPACTED --_—f_ FELL. OVEREXCAVATE AND RECOMPACT UNWEATHERED BEDROCK OR MATERIAL APPROVED BY THE GEOTECHNICAL CONSULTANT NOTE: Deeper overex_covotion and recompaction shall be performed if determined to be necessory by the geotechnicaI consultant. I 1 1 1 i 1 1 APPENDIX B 1 1 1 1 1 1 1 1 1 1 1 1 6820414-01 APPENDIX B REFERENCES UTILIZED Robert Stone and Associates, 1970, As -Graded Cross -Sections, Diamond Bar Tract No. 30578, dated January 9, 1970 (Job No. 1-68-301-02Z). 1970, Final As -Graded Geologic Report, Rough Grading Completed, Tract 30578, Diamond Bar, California, dated November 5, 1970 (Job No. 1-68-301-09). 1970, Soil Engineering Report on Compaction Testing, Tract 30578, Lots 1 through 188, and Tract 30289, Lots 6 through 8, Diamond Bar, County of Los Angeles, California, dated November 5, 1970 (Job No. 1-68-301-10). a p 'lu __ _{ 11,_\lam b pr II Ste!////i'-_1L J iJ. .. A /.. h`m