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HomeMy WebLinkAbout20210901121224431.pdfT. K. ENGINEERING CORP. Geotechnical & Environmental Consultants 3565 Lexington Avenue El Monte, California 91731 626)575-2856 - Fax (626)575-1582 LIMITED SOILS ENGINEERING INVESTIGATION REPORT Proposed 4 to 6 Feet High Retaining Wall & Swimming Pool Construction 2819 Crystal Ridge Road Tract 47850, Lot #26) Diamond Bar, California TKE Job No. 02-168F June 4, 2002 For Mr. Roger Yang A & C Construction, Inc. T. K. ENGINEERING CORP. Geotechnical & Environmental Consultants 3565 Lexington Avenue El Monte, California 91731 626)575-2856 • Fax (626)575-1582 June 4, 2002 A & C Construction, Inc. 316 Pasco Tesoro Street Walnut, CA 91789 Attn: Mr. Roger Yang TKE Job No. 02-168F) Subject : LIMITED SOILS ENGINEERING INVESTIGATION Proposed 4 to 6 Feet High Retaining Wall & Swimming Pool Construction 2819 Crystal Ridge Road (Tract 47850, Lot #26) Diamond Bar, California Dear Roger: We are pleased to present the following Limited Soils Engineering Investigation Report for the proposed 4 to 6 feet high retaining wall & swimming pool construction at the subject site. This work was performed in accordance with our proposal dated May 21, 2002, and was accepted by you. A preliminary evaluation of the subsurface condition was made with respect to the proposed structure. The results of our studies indicate that the site is suitable for the proposed development from a geotechnical engineer's standpoint, if the recommendations presented in this report are incorporated into the design and construction. Thank you for the opportunity to be of service on this project. PIease contact the undersigned, if there is any question concerning this report. Respectfully submitted, T.K. ENGINEERING CORP. Wan Lain-Allan) Tsai,/R( Principal XC: (4) Copies: Addressee z A2lMaA O TABLE OF CONTENTS COVER LETTER TABLE OF CONTENT 0914110 owlyAli .: 9 Page No. SCOPEOF WORK................................................................. 1 PROJECT DESCRIPTION....................................................... 2 SITE CONDITIONS....................................................... 2 FIELD AND LABORATORY INVESTIGATION ........................... 3 SUBSURFACE CONDITIONS ............................................. 3 CONCLUSIONS AND RECOMMENDATIONS ................. General............................ I .......................... 4 Site Preparation .............................................. 4 Foundation....................................................... 5 Bearing Capacity .............................................. 5 Lateral Resistance ..................................... 5 Retaining Wall Design ...................................... 6 Foundation Settlement ..................................... 6 Seismic Parameters ...................................... 7 Wall Backfills............................................... 7 Concrete Slab On -Grade ........................................ 7 Swimming Pool ............................................... 8 Slope Maintenance ........................................... 9 Temporary Excavation ...................................... 10 Drainage ............ 11 Construction Observation & Testing ................... 11 REMARKS...................................................................... 12 APPENDIX A - Exploration and Laboratory Testing APPENDIX B - .General Specifications for Site Grading & Excavation APPENDIX C -'REFERENCE Plot Plan............................................................... Plate A-1 Log of Test Pit ............................................. Plates B-1 & B-2 Shear Test Diagrams ............................................. Plate D-1 Proposed 4 to 6 ft, high retaining wall & swimming pool Job No. 02-168F 2819 Crystal Ridge Road June 4, 2002 Diamond Bar, California SCOPE OF WORK This report presents the results of a limited soils engineering investigation for the proposed 4 to 6 feet high retaining wall, and swimming pool construction at the subject site. The locations of proposed retaining wall, swimming pool, and test pits are shown on the attached Plate A-1. Our exploration was limited to the area of proposed retaining wall and swimming pool and this was based on the preliminary landscape plan, prepared by A & C Landscaping, Inc. dated 5/14/2002. The investigation was conducted in accordance with generally accepted geotechnical practice. This investigation was also authorized to determine the static and physical characteristics of the soils beneath the site for design purpose. This investigation includes the following steps: Review of the Geotechnical Report of Rough Grading for Lots 1 through 26, 29 through 36, Parcels A through G, and Lots 45-50, Tract 47850, Diamond Bar, prepared by Harrington Geotechnical Engineering Inc., dated 6/2/1998. HGEI Project No. 98-02- Geotechnical reconnaissance of the existing site conditions. Logging, and sampling of two (2) test pits, excavated by the client at the subject site. Laboratory testing of the representative samples of on -site earth materials to determine their properties. Review and engineering analysis of the test data with respect to the proposed structure. Preparation of this report. Page 1 T.K. ENGINEERING CORP. Proposed 4 to 6 ft. high retaining wall & swimming pool Job No. 02-168F 2819 Crystal Ridge Road June 4, 2002 Diamond Bar California The results of the field exploration and laboratory tests, which form the basis of our recommendations, are presented in the attached Appendices. PROJECT DESCRIPTION Based on the preliminary landscape plan prepared by A & C Landscaping, Inc., and information provided by the client, it is our understanding that the proposed development is to construct a 4 to 6 high retaining wall on the existing 2: 1 descending slope at the south and west of existing 2-story house and a swimming pool at the back yard. The purpose of this retaining wall is to expand the backyard and side yard for landscape and hardscape improvement. No grading plan is available for review. However, it is our request when foundation and grading plans become available, they should be forwarded to this office for review prior to construction. SITE CONDITIONS The subject site is a hillside lot located on the south side of Crystal Ridge Road, in " The Country" a gated community, at the City of Diamond Bar, California. The surrounding areas have been developed with single family houses and graded vacant lots. The subject property contained a 2-story single family house with an attached garage. The residential structure is located on the front (i.e. north) portion of property and is on a pre -graded Page 2 T.K. ENGINEERING CORP. Proposed 4 to 6 ft. high retaining wall & swimming pool Job No. 02-168F 2819 Crystal Ridge Road June 4, 2002 Diamond Bar California flat pad. The flat pad is surrounded by a 2 : 1 descending slope on the east, west and south. The proposed retaining wall will be located on the existing south and west 2:1 descending slope. And the proposed swimming pool and spa will be located on the existing flat back yard area. At the time of our exploration, the proposed construction area was vacant, but contained some vegetation. FIELD AND LABORATORY INVESTIGATION Field exploration was performed on May 28, 2002. Two test pits were excavated to a depth of 8.5 feet to 9 feet below the existing ground surface within the existing back yard area. Approximate locations of the test pits are shown on Plate A-1. Selected samples obtained during field exploration were tested in the laboratory. A description of the field exploration and laboratory testings are presented in Appendix A. SUBSURFACE CONDITIONS The subsurface materials encountered in the test pits are consisted of compacted fill. Based on the geotechnical report of rough grading for tract #47580, the fill had been certified by Harrington Geotechnical Engineering Inc. However, the test pit logs indicate that the top 1 to 2 feet fill is relative loose. Details of description for subsurface soil conditions are presented in the pit logs, Plates B-1 & B-2. Page 3 T.K. ENGINEERING CORP. Proposed 4 to 6 ft. high retaining wall & swimming pool Job No. 02-168F 2819 Crystal Ridge Road June 4, 2002 Diamond Bar, California Neither groundwater nor seepage was observed in the either of two test pits to the drilled depths. CONCLUSIONS AND RECOMMENDATIONS General The information obtained during our investigation indicated that the subject site is suitable for the proposed development provided that the following recommendations are incorporated into the design, and in the job specifications, and are implemented during the construction. It should be noted that the recommendations contained herein are intended to serve as guidelines to provide the project design consultants with preliminary design parameters. Prior to construction, any geotechnical related plans and/or documents should be reviewed by the soils engineer so that such plans and documents will comply with our recommendations. Any need for revised recommendations will be given upon the review. Site Preparation According to the preliminary landscape plan, prepared by A & C Landscaping, Inc., fill up to 6 feet will be needed for the retaining wall backfill. It is recommended that the top 1 to 2 feet loose soils within the proposed retaining wall footing, retaining wall backfill, and concrete slab on -grade areas be removed and recompacted to at least 90 % relative compaction. Bottom of excavation should be scarified, moistened, and properly compacted to a minimum of 90% relative compaction for at least upper 8 inches. Page 4 T.K. ENGINEERING CORP. Proposed 4 to 6 ft. high retaining wall &swimmJob No. 02-168Fing poolJune4, 2002 2819 Crystal Ridge Road Diamond Bar California Acceptable fill material should be placed in thin lifts not exceeding 6 inches in thickness when loose and should be properly compacted to at least 90 percent of the maximum dry density as determined by ASTM Test Method D1557. Bottom of removal for unsuitable materials and placement of compacted fill should be performed under the observation and testing of the Soil Engineer or his representative. All site grading should comply with the applicable portion of the City of Diamond Bar grading code and the General Specification attached in Appendix B. Foundation For adequate support of proposed 4 to 6 feet high retaining wall, we recommend that all footings be embedded at least 18 inches into competent ground. The footing should be reinforced with at least four (4) rebar #4, 2 placed near the top and 2 placed near the bottom. Footing, located on or adjacent to a descending slope , should have a minimum of 7 feet setback, measured from the outer edge of footing to the slope surface. Bearing Capacity An allowable soil bearing pressure of 1500 psf may be used for footing placed as recommended. The above value may be increased by 33 % when considering short duration seismic or wind loads. Lateral Resistance Resistance to lateral loads may be provided by friction acting on the base of footings and by passive Page 5 T.K. ENGINEERING CORP. Proposed 4 to 6 ft. high retaining wall & swimming pool Job No. 02-168F 2819 Crystal Ridge Road June 4, 2002 Diamond Bar California earth pressure. Coefficient of friction between the base of footings and competent compacted fill or bedrock may be assumed as 0.35. An allowable lateral bearing value against the sides of footings is recommended to be 250 pounds per square foot per foot of depth to a maximum of 2500 pounds per square foot for the footings in contact with competent compacted fills. No passive pressure can be used in the design until the footing meets the 7 feet setback. Seismic Parameters Based on the UBC's Seismic Map, the recommended seismic parameters are as follows: Soil Profile Type: SD Ca = 0.44 Na Cv = 0.64 Nv Na = 1.3 Nv = 1.6 Seismic Source Type: B Retaining Wall Design The recommendations for retaining wall design are as follows: 1. Where free-standing retaining structures are proposed, an equivalent fluid pressure of 40 pounds per cubic foot (Le. pcf) may be used in the design, provided a level, backfill is maintained. For the surcharge load induced by the adjacent structures and service conditions, a coefficient of 0.4 may be used to convert the surcharge load in a uniform distribution force to the wall, if the surcharge load is located within the distance less than the height of wall. All backfill should be compacted to at least 90% relative compaction and should also be tested at every 2-foot vertical interval or less. Page 6 T.K. ENGINEERING CORP. Proposed 4 to 6 ft. high retaining wail & swimming pool Job No. 02-168F 2819 Crystal Ridge Road June 4, 2002 Diamond Bar California 2. All design pressures assume that sufficient drainage will be provided behind the walls to prevent the build-up of hydrostatic pressures from surface water infiltration. Adequate drainage may be provided by means of a system of subdrains and/or weep holes with filter materials installed behind walls. Foundation Settlement Settlement of the footings placed as recommended and subject to no more than allowable loads is not expected to exceed one inch. Differential settlement between adjacent columns is not anticipated to exceed 1/2 inch. Wall Backfrlls All wall backfills should be properly compacted to at least 90% of laboratory maximum dry density. Wall backfills should be tested at every height not to exceed 2 feet. Care should be taken when compacting adjacent to walls. Improper compaction techniques or equipments can produce excessive lateral loads. Concrete Slab On -Grade The on -site soils are considered to be medium to high for expansion potential. If the recommendations for site preparation are followed, concrete slab -on -grade supported on compacted fill should have a minimum thickness of 4 inches, and be reinforced with at least rebar #4 bar, 18 inches on centers, both ways, or its equivalent placed at slab mid - height. Page 7 T.K. ENGINEERING CORP. Proposed 4 to 6 ft. high retaining wall & swimming pool Job No. 02-168F 2819 Crystal Ridge Road June 4, 2002 Diamond Bar California Extra care should be exercised to ensure the placement of reinforcement at the slab med-height. The reinforcement placed at or sagged to the bottom of slab will provide no reinforcement effect and unusual cracks may develop on the slab. Where upward capillary of moisture is not desired, a moisture barrier, such as vinyl membrane with a minimum thickness of 6 mils, should be placed beneath the concrete slab. A minimum of 4-inch wash sand or gravel should also be provided beneath the concrete slab. The membrane should be covered by 2 inches of sand to aid in uniform curing of the concrete. Care should be taken not to puncture the membrane. Prior to placement of concrete, the subgrade soils should be pre -saturated to at least 12 inches. Swimming Pool a. The proposed swimming pool wall may be designed as not -restrained wall. A minimum equivalent fluid pressure of 62.4 pcf may be used in the design. b. The setback between the pool and the top of slope or retaining wall should be at least 10 feet. if the setback is less than 10 feet, that portion of the pool wall within a horizontal distance of 10 feet from the top of slope or retaining wall should be capable of supporting the water in pool without soil support. C. The entire pool bottom should be embedded into the competent ground. Page 8 T.K. ENGINEERING CORP. Proposed 4 to 6 ft. high retaining wall & swimming pool Job No. 02-168F 2819 Crystal Ridge Road June 4, 2002 Diamond Bar California d. The pool should be designed for any possible surcharge loading from nearby structures, should the pool/spa fall within a 45- degree plane (1;1) from the surcharging structure. e. Adequate drainage system should be provided around the pool and pool deck area. All surface water should be directed away from the pool and pool deck toward the approved drainage devices. Slone Maintenance We recommend that the property owner maintain an adequate debris, erosion and fire control program to protect the property. Sloughing and slumping of the slope surface may be anticipated if the slopes are left unprotected over a period of time, especially during rainy seasons. It should also be noted that excessive landscape watering, rodent burrows and uncontrolled surface runoff may cause instability of the slope surface. The following recommendations are provided so as to minimize the potential for future erosion of the slope at the subject site. 1. The slope should be planted as soon as possible with suitably deep-rooted and drought resistance vegetation. It is imperative that landscape watering be kept to the minimum required for normal plant growth. Irrigation system should be checked on a regular basis for its leakage. Any leaking encountered should be repaired immediately. Additional protection may be provided by use of jute mesh or suitable geofabrics. If adequate ground Page 9 T.K. ENGINEERING CORP. Proposed 4 to 6 ft. high retaining wall & swimming pool Job No. 02-168F 2819 Crystal Ridge Road June 4, 2002 Diamond Bar California cover is not established before the rainy season, sloughing and slumping of the surficial soils may occur. 2. A berm or drainage channel should be placed at the top of slopes to prevent the flow of water over the top of the slope. Paved drainage swales and downdrains on the slope and drain inlet should be kept free of soils and debris. All drainage system should be periodically cleaned up and properly maintained to insure its function. 3. During the rainy season, plastic sheets should be placed over the slopes to prevent runoff water from eroding the slope surfaces if adequate ground cover is not established. Temporary Excavation Unsurcharged temporary excavations may be cut near vertical up to 5 feet and sloped back at a ratio of 1 : 1 or flatter. During the rainy season, berm should be constructed and maintained on top of slope to prevent runoff water from eroding the slope faces. Tops of excavation should be barricaded at least 5 feet from the cut to prevent any storage or equipment loads. We also recommend that a representative of this office be present during the excavation so the need of modification or additional recommendations can be made at that time if different conditions are found. All excavation should be performed in accordance with the current standards delineated in CAL - OSHA for safe working conditions. Page 10 T.K. ENGINEERING CORP. Proposed 4 to 6 ft. high retaining wall & swimming pool .lob No. 02-168F 2819 Crystal Ridge Road June 4, 2002 Diamond Bar California Drainage Drainage control is imperative for continued site stability. The risk of unusual settlement or slope instability can be reduced by proper drainage control and maintenance of slopes and yards. It is the responsibility of the homeowner to maintain slopes and drainage facilities and correct any deficiencies found during occupancy of the property. Adequate drainage system should be provided and designed by a civil engineer. All drainage should be directed away from the foundation areas toward the approved drainage devices. In no cases shall water be allowed to pond within the site or be drained down the slope in an uncontrolled and concentrated manner. Construction Observation and Testing As a necessary requisite to the use of this report, the following construction stages shall be observed and/or tested by a representative of this facility: 1. Temporary excavation. 2. Bottom of excavation prior to placement of any fill. 3. Placement and compaction of fill within the proposed retaining wall footing and concrete slab on -grade areas. 4. Foundation excavation prior to forming and pouring. S. Installation of subdrain system. 6. Placement and compaction of retaining wail backfiil. 7. The bottom of excavation for proposed swimming pool. Page 11 T.K. ENGINEERING CORP. Proposed 4 to 6 ft. high retaining wall & swimming pool Job No. 02-168F 2819 Crystal Ridge Road June 4, 2002 Diamond Bar, California 8. Pre -saturation of subgrade soils within the areas for proposed concrete stab on - grade. If T.K. Engineering Corp. is not allowed to perform sufficient observations and adequate testing during construction, a statement regarding suitability and stability of the project can not be made accordingly. It is recommended that a joint meeting among the client, contractor, and the soil engineer be held at least 2 days in advance of the commencement of construction to discuss specific procedures and scheduling. REMARKS This report is prepared based upon the proposed project as described, observation and findings during field investigation, and evaluation of the test results. The conclusions and recommendations are based upon the assumption that soil conditions do not deviate significantly from those described herein. If variations from our findings or undesirable conditions are found during construction, or if the proposed construction differs from that presently planned, T.K. Engineering Corp. should be notified so that supplemental recommendations can be given. This report is issued with the understanding that it is the responsibility of the client to transmit the information and recommendations of this report to developers, owners, buyers, Architects, Engineers, and Designers for the project so that the necessary steps can be taken by the Contractors and Subcontractors to carry out such recommendations in the field. The conclusions and Page 12 T.K. ENGINEERING CORP. Proposed 4 to 6 ft. high retaining wall & swimming pool Job No. 02-168F 2819 Crystal Ridge Road June 4, 2002 Diamond Bar, California recommendations contained in this report are solely professional opinions derived in accordance with current standards of professional practice. This report has been prepared in accordance with generally accepted engineering practice and no warranty is expressed or implied. All exploratory borings or pits used for subsurface exploration were backfilled with reasonable effort to restore the areas to their original condition. As with any backfill in an area as small and deep as a boring, some consolidation and subsidence of the backfill soils may result in time, causing some depression at the boring area and possibly a potentially hazardous condition. The client and/or owner of the property are advised to periodically examine the boring area, and if necessary, backfill any resulting depressions. T. K. Engineering Corp. should be retained during construction of the project so that continuous observation of the subsurface conditions can be made and additional recommendations can be given in the event of any change of condition. If another firm is retained for geotechnical observation and testing services, our professional responsibility and liability would be impaired. Page 13 T.K. ENGINEERING CORP. Proposed 4 to 6 ft. high retaining wall & swimming pool Job No. 02-168F 2819 Crystal Ridge Road June 4, 2002 Diamond Bar, California _ APPENDIX A EXPLORATION AND LABORATORY TESTING FIELD EXPLORATION Field exploration was performed by excavating two (2) test pits. The test pits were carried to depths of 8.5 feet to 9 feet below the surface. The encountered soils were continuously logged by our field personnel and classified by visual examination. Relatively undisturbed samples and representative bulk samples were obtained for laboratory testing. Relatively undisturbed samples of soils were observed at frequent intervals by driving a thin -wall steel sampler with successive drops of a hammer. The soils were retained in brass rings of 2.5 inches in diameter and one inch in height. Normally, the central portion of the sample is retained in a plastic container for shipment to the laboratory. The locations of test borings are shown on Plate A-1. Description of the encountered soils are presented on B-Plates. LABORATORY TESTING Classification The field classification was verified in the laboratory. The final classification is shown on the B- Plates. Moisture -Density The field moisture content and dry unit weight are determined for each of the undisturbed soil samples. The dry unit weight is determined in pounds -per -cubic -foot. The field moisture content is determined as a percentage of the dry weight of the soil. Both the field moisture content and the dry density for each of the tested sample are shown on B-Plates. Shear Tests Shear tests were performed on selected ring samples to evaluate the shear strength of representative on -site soils. The samples were tested following a soaked period of at least 24 hours. Each sample is sheared at a constant rate of displacement of 0.015 in/min under a load of 1000 psf, 2000 psf and 4000 psf. The results are plotted on the Plates D-1 and D-2. T.K. ENGINEERING CORP. Proposed 4 to 6 ft. high retaining wail & swimming pool Job No. 02-168F 2819 Crystal Ridge Road June 4, 2002 Diamond Bar California APPENDIX B GENERAL SPECIFICATIONS FOR SITE GRADING AND EXCAVATIONS The recommendations presented in the geotechnical report are part of the earthwork and grading specifications, and shall supersede the provisions contained hereinafter in case of conflict. Evaluation performed by the consultant during the course of grading may result in revised and/or additional recommendations, which in turn, will supersede these specifications or the recommendations of the geotechnical report. It is necessary that the consultant provide adequate testing and observation so that the earthwork will be accomplished in accordance with the specifications. It shall be the responsibility of the contractor to assist the consultant and keep him apprised of work schedules and changes so that the consultant may schedule his personnel accordingly. 1. All existing fill, near surface loose or soft soils, vegetation, debris and disturbed soils in structure, slab or pavement areas shall be excavated. The excavated areas shall be observed by the Soil Engineer. 2. Areas to receive compacted fill shall be scarified to a depth of at least 6 inches and moistened, as required, to obtain near optimum moisture. Scarification shall continue until the soil is broken down and free of large clay lumps or clods and until the working surface is reasonable uniform and free of uneven features. The scarified areas shall be A) compacted to at least 90 % of the maximum dry density as determined by the ASTM D 1557-78 compaction method, or B) compacted and approved by the Soil Engineer. 3. Any loose pockets, soft, dry, spongy, highly fractured or otherwise unsuitable soil, extending to such a depth that surface processing can not adequately improve the condition, shall be overexcavated down to firm ground. The excavated areas shall be observed and approved by the Soil Engineer prior to placing compacted fill. 4. Fill, consisting of soil approved by the Soil Engineer, shall be placed in controlled layers with appropriate compaction equipment. Each layer shall be compacted to at least 90 % of the laboratory maximum dry density for the material used. The field density shall be determined by the ASTM D-1556 Sand Cone Method or equivalent. 5. The excavated, on -site clean fill material is considered satisfactory for re -use as compacted fill. All imported fill shall be non -expansive and approved by the Soil Engineer prior to use in the fill areas. Rocks larger than 6 inches in diameter shall not be used. T.K. ENGINEERING CORP. Proposed 4 to 6 ft. high retaining wall & swimming pool Job No. 02-168F 2819 Crystal Ridge Road June 4, 2002 Diamond Bar, California 6. 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, the geotechnical recommendations and specifications presented herein, and the approved grading plans. Observation and field tests shall be performed during grading by the Soil Engineer to assist the contractor in obtaining the required degree of compaction and the proper moisture content, Where compaction of less than 90 % is indicated, additional compactive effort shall be made with the adjustment of the moisture content as necessary until 90% compaction is obtained. 7. No fill soils shall be placed during unfavorable weather conditions. When work is interrupted by rains, fill operations shall not resume until the field tests by the Soil Engineer indicate the moisture content and the dry density of the fill are as previously specified. 8. Where fill is to be placed on the ground with slopes steeper than 5 : 1 (horizontal : vertical), the ground shall be stepped or benched. The lowest bench shall be a minimum of 15 feet wide, at least 2 feet deep, shall expose firm materials and shall be approved by the consultant. Other benches shall be excavated in firm materials for a minimum width of 4 feet. Ground sloping flatter than 5 : 1 shall be benched or otherwise overexcavated when considered necessary by the consultant. T.K. ENGINEERING CORP. PLOT PLAN Crystal Ridge Road 1 f Existing Residence F z Proposed Swimming Pool. 1 Proposed Retaining Wall F Approximate Test Pit Location Proposed 6 Feet High Retaining Wall & Swimming Pool. Construction J 0 B NO. 02-168F 2819 Crystal Ridge Road Diamond Bar, California SCALE 1 "= N/A T.K. ENGINEERING CORP. PLATE A-1 GEOTECHNICAL & ENVIRONMENTAL ENGINEERS Project: Proposed 6' High Retaining Wall & Swimming Pool. Const. 2819 Crystal Ridge Road Diamond Bar, California LOG OF TEST PIT NO. Date of Excavation: 5/28/2002 Excavation Contractor:A & C Construction Size of Test Pit: 9'x 3.5'x 8.5' (L x W x D) Remarks: Driving Energy: Co c AO m SUMMARY OF TEST PIT This test pit log repared ,by Flf. Engineering Corp. applies only at the sic excavation locatlon , andatmeoexloratidn. Subsurface conditions may drfter at other locations and may change atthisnwithtme. LABORATORY TESTS a 3 c c: 7i u Im a L be 3 +' W v 0 o tA Surface Elevation: + 0' Water E]evabon: Not encountered Reference: Backyard Surface DESCRIPTION 1 2 3 4 5 s 8 9 1 11 12 13 14 1 16 17 18 19 21 22 23 24 2 2s 2l 2$ 29 Sandy silty clay with rock fragments, dry to moist — brown/yellowish brown End of pit at 8.5' CL CH 99. 3 103. 2 11. 6 16. 9 Job No. 02-168F T.K. ENGINEERING CORP GEOTECHNICAL ENGINEERS PLATE g. 1 Project: Proposed 6' High Retaining Wall & Swimming Pool. Const. 2819 Crystal Ridge Road Diamond Bar, California LOG OF TEST PIT NO. 2 Date of Excavation: 5/28/2002 Excavation Contractor:A & C Cbnstruction Size of Test Pit: 11'x 3.5'x 9' (D x W x D) Remarks: Driving Energy: UL c N d 6 a o SUMMARY OF TEST PIT This test pit log prepared by TX Engineering Corp. applies only at the specific excavaWn kcatlon, and pt the time of a lore#on. Subsurface conftons may differ at other locsdions and may change at this location with?me. LABORATORY TESTS a rn a u a dP s° o p Sru4aca Bevafion: ± 0' Water Devaton: Not encountered Reference: Backyard Surface DESCRIPTION 1 2 3 4 5 fi 7 s s 1 11 12 13 14 1fi 17 18 13 2 21 22 23 24 2 26 27 28 29 Sandy silty clay with rock fragments, damp to moist — brown/yellowish brown End of pit at 9' CL IGH 101.3 102.4 12.6 17.8 x X Job No. 02-168F T.K. ENGINEERING CORP. GEOTECHNICAL ENGINEERS PLATE B- 2 5.0 4.5 4.0 3.5 3.0 a w a 1.5 1.0 0.5 0.0 6- 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 NORMAL STRESS, ksf TEST PIT NO.: TP-1 DEPTH: 3' DESCRIPTION: silty clay with rock fragments STRENGTH INTERCEPT (C): 0.3 ksf FRICTION ANGLE (0): 20 Degrees REMARKS: Soil samples tested at increased moisture Project: Proposed 6 Feet High Retaining Wall Swimming pool Construction DIRECT SHEAR TEST 2819 Crystal Ridge Road Diamond Bar, California RESULTS Job No. 02-168F T.K. ENGINEERING PLATE D — 1 GEOTECHNICAL ENGINEERS