HomeMy WebLinkAbout30577 (199)10
10
10
ICS
RICHARD MILLS ASSOCIATES, INC.
9223-C Archibald Avenue
Rancho Cucamonga, California 91730
714) 980-1751
MN f'kINEERING GEOLOGY
SECTION
GRADING PLAN REVIEW
For Lot 65, Tract 30577
Diamond Bar, County of Los Angeles
and Response to County of Los Angeles
Geo I ogic Review Sheet dated Feruary 26, 1981.
um
CORNER CONSTRUCTION
14763 Proctor Avenue
City of Industry, California
April 23, 1981
TABLE OF CONTENTS
Page
Response to County Review Sheet
Grading Plan Review 2
Illustrations:
Geologic Map 1" = 20' Pocket
Cross Sections:
1A-lA' (Plate R-1) I" = 20' Following Page 5
IB -IB' (Plate R-2) 11 = 20' Following Page 5
From Referenced Report*
Geologic Map - Plates I and 2) 1" 40'
Cross Sections
A -A' (Plate 3) 1" = 401
3-E1' -B" (Plate 4)
Logs for Trenches 1, 2, (Plate 5), and 3 (Plate 6) 1" 5'
Referenced Report (riot included)
Geotechnical Investigation for the proposed residence at Lot 65,
Tract Number 30577, Diamond Bar Area of Los Angeles County,
California; by Richard Mills Associates, May 13, 1977.
Response to County qic Review Sheet
Our responses are in order of remarks 1-3 on the Review Sheet.
la. A geologic map based on the latest revised grading plan (dated
Dec. 12, 1980) is enclosed.
lb. New Geologic Sections 1A-lA' and 1B-IB' based on the revised grading
plan have been prepared and are enclosed, Section 1B-I3' includes
proposed grading on adjacent lot 66. (See also Conclusions and
Recommendations, #5 below).
Ic. Evaluate the effect of the proposed development. (See Conclusions
and Recorrimendations 1, 2, and 3 below).
Id. Clarification of the geologic sections in the above referenced report.
Cross Section A-A' was submitted to show the geometrWy ofthe
existing old stable landslide on lot 65, and that the stability
of the landslide would not be adversely affected by anticipated
normal grading for the proposed residence. The depth to the slip,
surface of the old slide is estimated at 24-31 feet (see p. 9 of
referenced report) . The rriaximum depth of proposed excavations for
retaining walls or cut slopes is 9.0+ feet. In our opinion, these
excavations will not adversely affect the stability of the old
landslide.
Cross Sections B--D' -B" (consisting of two cross sections in
two difference direct-ions) were submitted primarily to show the
natural._ slope stability relations, because a grading plan was not
available.
The conclusion that the natural slopes are stable (p. 9 of
referenced report) is still valid, but Cross Sections B-B'-B" are
largely superceeded by attached Cross Sections IA-lA' and IB-IB'
that accompany this grading plan review.
1) {
gip-14 3
1*
U
10
10
10
U
10
I&
U
10
The elevations on Cross Sections B -B' -B", and the plotted
lengths of A -A' and B' -B" were incorrectly transposed from the
working off -ice copies to Plates 2 and 4 in the above referenced
report. Corrected Plates2 and 4 are resubmitted with this
report.
le. Classification of Geologic Terminology
The abbreviations (Ss and Sit) representing interbedded
sands -tone and siltstone, and (Ss or Sh prtngs) representing inter-
bedded sandstone and shale partings have been printed on the graphic
logs (attached Plates 5 and 6).
The Qal and Col unit (mixture of alluvium and colluvium) is
shown on the attached grading plan. It consists of tan clayey silt
and brown silty clay where estimated to be thicker than 4.0 feet.
If. Compliance with Section 309
See conclusion 8 and 9 below.
Grading Plan Review
This review is based on the Plot Plan -Grading Plan prepared by
John B. Abell, Inc., 5658 E. Beverly Boulevard, Los Angeles, ("'alifornia,
Sheet I of 2, dated December 12, 198,0; Scale 1" = 2(l').
Geologic considerations include primarily excavation of a 2:1
cut slope tip to 15± feet high and 180± feet long, a retaining wall
excavati on tip to 9 fee t h i gh and 8(l± feet I ong), seepage pi is , and mi nor
fill on the northeast side of the proposed residence.
2) P-1 43
10
10
10
10
U
19
10
19
U
10
10
Conclusions and Recommendations:
I. Cut Slopes: The proposed 2:1 cut is expected to be locally
0
unstable with adverse apparent dips varying from 7 to
230
Therefore, lateral support in the form of an equipment
width (12' approximately) stabilization blanket is recommended
for this slope.
2. ,R.e,.t a i r.i i a W_a-41 J s : The retaining wall in the garage Ariveway
area (80± feet long and 8± feet high) may require a bedding
plane surcharge load equivalent to approximately 25 degrees.
We recommend that the actual bedding plane Surcharge, load
be determined during in -grading inspections and incorporated
at that time into the retaining wall design.
3. SAY epa_9_t._Fj_t§_.- Two pits are located 60± feet away from and below
any proposed Cut',.
Assuming normal percolation in conjunct -ion with the require-
ment that percolation is prohibited in the upper 10 feet of each
pit, seepage problems on site or off site are not anticipated,
4. Fill: Only minor fills are indicated on the plans. These should
be constructed according to the grading recommendations of the
referenced report (Mills 5-13-77).
5. Relation to adjacent lots: The proposed design includes rM
large cuts or fills, and no seepage pits near the eastern
property line. Thus the proposed grading will not adversely
affect existing development on Lot 64.
3) P-143
The 15± feet high cut slope along the west property
line stabilized as recommended will not adversely affect
the proposed grading on lot 66.
6. Drainaqe: A concrete swale has been designed to intercept the
slopewash from the ypslope area west of the proposed construc-
tion site.
7. The Conclusions and Recommendations of our above referenced
report remain as stated with the exception of 2c. It is super-
ceeded by #1 and #2 of this report regarding cuts or retaining
walls.
8. The proposed construction is considered safe from hazards of
landslides, settlement, or slippage; and will not adversely
affect the geologic stability of adjacent lots provided the
recommendations in this and the above referenced report are
followed.
9. The proposed construction is located on an old mapped landslide,
but appears geologically safe because:
1) The landslide has a safety factor of 1.5 according to the
geologist of previous record (See Ref. A, p. 5 in our above
referenced report) .
2) Proposed grading to maximum depths of 9± feet is not ex-
pected to intercept the old landslide slip surface at estimated
depths of 24-31 feet.
4) P-143
1*
10
C]
10
10
10
I*
U
I*
I*
U
10. The Grading Plan is approved subject to the recornt,,iendaticans
so=
Respectfully submitted,
RTICHARD MILLS ASSOCIATES
L. J. Herber
R.G. #3642
Richard B. Mills
President
CEG #114
5)
P-143
0
El
I*
m
N
w n r- cuN _,
VI lf7 Cl.+.>
0CEJ J -Y ro II
Mr C .ya a. O? C W
b w
aro
V
lb ft. aJ J-% ^ro
N a > C71
0
a CC5
c c a 4- "CT
N 4dJ
M a 4
u5 N
4i7 tNUy a r%• 5,,,
a 0 N n= °v v ro o c3 c cr
0 6. J 0 4- 0 LT
Lo a tl) N N I V •
prn
u. Yu 0) 0764- to .ac > a
cw
1tenOrs
au
cN 'rocw
41 a + 4-' O
s a w + - a
ae
ar res Ya .c .c — a a .a -r + p
N CI"
T
y
co
N
r CV d Irl M1(w.
4
Cl: 1
0 CC'S w-. i d
7 0vi
a c +a
1
O I
CS., M
I
cwl
N "
41
ko CL
C7 N a. CT:
Y a. a
ca 00 , ..y. W
10
I f
I
m/i c
c
ro41 Mb / v
W
w
C" F
rai
0-
CD C7 C.i C7
tO1YY 11YYeYYV pXM51p*!MI'YiN NY'VYp/Nrt "Y1YA 4N!'SVMS NIV2d1 nM 1p'pMY NtlYI NNLLIVYOY>...........
10
10
10
10
I*
is
I*
U
I*
KI
U
FILL
j_._1_ Compacted fill placed under the supervision of the
geologist of previous record.
I a I C_l
Tan clayey silt and brown silty clay to greater than
4.0 feet in depth. Partially colluvial and alluvial
in origin.
Ss+Sl-'t —Interbedded sandstone and siltstone of the Puente
formation (Sequel member).
Contacts, inferred and approximately located.
Bedding Attitude.
Bedding Attitude; generalized.
Syncline axis.
Test pit locations.
Location of Cross -Sections.
Data from Geologist of previous record
Reference A & B)
7
L Bedding Attitude.
4 Synclinal axis.
Anticlinal axis.
7 P-//' Attitude of slide plane with depth below surface
long arrow indicates plunge direction of slicks).
7, Attitude of shear plane.
f-+-Buried limit of old landslide.
Boring Locations (off-site). 077
Job No. P-143
wv
VT_M
w.. _ .. PLO ALAN
Scale: 1" m°° 40"
Oal+Col
o .
9 6
kk
77
e ,
Z I /
05 I
Ss t
Fill
104)
0
kk
Ile
Ar' 0
Fill
14-
AGLI=S NLS ` DRIVE
Richard Mills Associates, Inc.
Job No. P-14:1 PLATE 2
10
0
0
0
0
co
1-7
0
0
0
0
C-)
0
T-
C")
co
Job No. P-143
CDJ,
4-J
y
Y
D
cy
a) (U
Y
PCS
cu
t
kc) y
C.
4-)
4-)
4-
4 4t1
V) 0 W
4-)
0
C)
ftl
C"') —i
It
4
T-
C")
co
Job No. P-143
CDJ,
4-J
D
a) (U
PCS
4-1 4-3
4- ea
V) 0 W
0.
4
IN 6
0 V)
t C
4--) -0 0 CYD S-1
4--
0) 0 CO
V)
C) X 0 u M—
r"a1 U
V
4. V)
LO
a9 r
rX
V) 0
4J
4-) (M
1) 0
W 5-- u
V)
4-)
V)
0 co v 0
0 Id, q)
T-
C")
co
Job No. P-143
CDJ,
PLATE 3
4-J
D
a) (U
X.:
4-1 4-3
4- ea
t C
4--) -0 0 CYD S-1
4--
0) 0 CO
V)
C) X 0 u M—
r"a1 U
4. V)
a9 r CJ V) 0
4-) (M
1) 0
W 5-- u
V)
4-3 M
V)
0 co v 0
0 Id, q)
E
erj 0 0
4-- u
3) X (TI
r_ V) 0 0 C.
a) I V S- 0 kiJ
ft$ 0
4-) 0 4-)
4J
A 0
4-
00
u C: 0
0 ct 0 0
4- -,- C: -,-- F: 4- 4-)
S- Lr) MJ 4-J c",
3 C.) a9 411 0 (n 0
V) I V) Tj Cl. U
U
eF) 4-) 0
I Ul a) 1 cu
0) D U
klo 'V t 7c Tj 0 n >
CU I q) V f+- .,.- 0 0
4-5 T-1 C v--- 0 4-1
V C•") Ira a) V) CL 0
C, 0-C w r- D" V +J
ets CU 0 L. r — d a) 0 0
i CX Z11 C% J V) Cyl C.
0 0 < V)
Cl 4-5 (V C.)
ro -e^. r
V) V) (D
I I f
0 4-J
CO r...
V)
Cy
PLATE 3
0
0
0
0
0
0
0
0
0
0
LO
k.0
I'D
2n
a
03
0
Vill C)
C) C)
Job No. P-143
a
C.0
r.
C
LU
A
I
V)
V)
CD
Richard Mills Associates, Inc.
PLATE 4
V)
C)
Ce
LIJ
DIC
A_ C.) VII N
CD 49
1,71
Ci
4J
Q) d
cz
ml
L
E
0 Aj
eo CS
W
pyo
Job No. P-143
a
C.0
r.
C
LU
A
I
V)
V)
CD
Richard Mills Associates, Inc.
PLATE 4
N I ow
11I 5'
0 TRENCH NO. I
lot,/
0XZQA1,
tv4,V
7W
0.0° - 0.,g Brown, porous, very fine sandy silt with
trace of clay (—S.L.-ID
0.8'- 2.5 Brown, moderately plastic silty clay 2)
M"- 4.5 Tan to brown clayey silt
0 4.5 8.0 Bedrock of interbedded soft brown siltstone
and soft fine to medium sandstone.
0 N50W
ilk 5k
TRENCH NO. 2
443W
S I t I&S
L--
7 /V 6r2
00:5
J--
0.0 1.0 Silt; similar to Trench No. 1, 0.0 0.3
0 1,x.1' 3.5 Clay; similar to Trench No. 1, 0A 2.5
3.5 7.0 Bedrock, interbedded silt tone and sandstone.
0
Job No. P-143
Richard Mills Associates, Inc.
0
PLATE
N12E
ill = 511
TRENCH NO. 3
71P WIdAq
0.0'- 0.8' Similar to Trench No. 1, 0.0 - 0.8; bUt withIlargerpercentsand.
t
0.8 - 2.0' Red clayey sand similar to Trench No. 1, 0.8 - 2.5
2.0'- 7.0" Bedrock, Interbedded sandstone and sandy shale.
I*
1*
I El
Job No. P--143
10
1
@ r
PL
r
g k- h ,R N
Abu;
711
Io—
ry
tIP619Pr ,
a
9PI1601-0fil"`A4MlPUjf0A;Fe) APPU04 401iow« W1 Mpml rl d&P
711, au,
p
w....w..„....„,..w„.. u-.»i.-„.,,. ,w.. .i w «www we,.w«w .w,. m,. ....a...w..,.:« R,nri w rxmmm.+....,.
Yli) hJ V'kb .....
a
u
s
A
ae
q
a
4
w,
a
s
a
s
lel
w
w
v
m r g,
I• i
Al
w,
r
k
r
n v'4
rw_
@ r
PL
r
g k- h ,R N
Abu;
711
ry
IRI u3 r + r ° w „"t
5+.!
i f I ' .I : 4,fi .v fA, Y ,.s 4 Y Y Y4 / *
I 4.^ b 1
u?
Y l
i,f i i'J9. f / V"' brV ,ryJ, y+, , i+uf
a F
F /
4 / V m` N r`6 '"ya” r Y d' n,
W, -
v
y ,v 7 rf n , rf l r % r 1 "r^t"'»J a o+ 1 Y r „
roo
Ag TOO,!,
vp
d
a 1 r
k
4!
v r vj
s
f a If I' M F "' a•= F f
a
rf
of to"
r
I
GLl
I
I
w