657, Construct a new SFR and pool d, Studies & ReportsA.G.I. GEOTECHNICAL, INC.
316 Tejon Place, Palos Verdes Estates, CA 90274 • (310) 378-4146
December 14, 1994
Del Amo Savings
3422 Carson Street
Torrance, CA 90503
Attention: Ms. Diana Bowers
Subject: INTERIM SOILS COMPACTION REPORT
Proposed Single Family Residence
Tract 30345, Lot 3
Sagebrush Lane
Rolling Hills, California
Dear Ms. Bowers:
Project No.: 4-1629-10
This report presents the results of observation and testing
performed during the preparation and placing of compacted fill at
the subject site.
Compaction tests were performed in accordance with ASTM:D-1556
(Sand Cone Method) and ASTM:D-2922 (Nuclear Method). The test
locations and limits of compacted fill for this report are shown on
the enclosed Plot Plan. Results of the tests are tabulated on the
enclosed "Compaction Test Results".
This report covers the slope reconstruction only. The building
areas and the remainder of the site will be reported on at a later
date. Further grading needs to be done to prepare this lot for
construction. This grading will take place when the size and
location of the proposed structures are determined.
Engineering Geology • Soil Engineering
Project No. 4-1629-10 Page 2
PREVIOUS GRADING
GENERAL
As discussed in a "Site History and In -Progress Report" by Keith W.
Ehlert, Consulting Engineering Geologist dated August 26, 1994,
Ehlert identified a previously existing fill key and the
approximate limits of the key delineated by means of an excavator
backhoe (a large track -mounted backhoe). The upper fills in the
key were removed and stockpiled. As the upper fill was removed,
the deeper fills appeared very firm and tight. Three exploratory
borings were drilled through the remaining fill in the key. The
borings were down -hole logged by Ehlert and the depth of the fill
determined. Undisturbed samples of the remaining fill were
collected and tested. The remaining fill was found to be well
compacted and suitable for support of fills to be replaced in the
key. Fill was then placed back into the excavation under our
observation as described under the Fill Placement section of this
report. Results of the laboratory testing of the fill are included
in the enclosed "Laboratory Test Results". The approximate limits
of the previously existing fill key as identified by Ehlert are
presented on the maps and cross sections included with the "As
Graded Geologic Report" by Ehlert dated December 9, 1994. Boring
logs are also included in the Ehlert report.
LABORATORY TESTING
Unit weight, moisture content, maximum density, optimum moisture
and direct shear tests were conducted on samples of the remaining
fill. The results of the direct shear tests are attached in
graphic forms. The results of the other tests are as follows:
Project No. 4-1629-10 Page 3
DRY DENSITY/MOISTURE CONTENT
Sample Sample Moisture Relative
Location Depth (ft.) Unit Weiaht (pcf) Content Compaction
B-2 5 90 16.6% 92%
10 97 15.2%
15 94 16.6% 98%
20 89 15.3%
25 94 16.1%
32 94 19.6%
B-3 5 92 16.6% 95%
10 96 14.4%
15 85 17.6% 93%
MAXIMUM DENSITY/OPTIMUM MOISTURE
Sample Sample
Location Depth (ft.) Maximum Density (pcf) Optimum Moisture
B-2 5 97.5 18.0%
15 96.0 21.0%
B-3 0-5 97.0 19.0%
15 91.5 25.0%
Based on the results of the laboratory testing, the remaining fill
is capable of supporting the new fill without adverse affects.
Project No. 4-1629-10 Page 4
309 STATEMENT
It is our opinion that the site can be developed without hazard of
landslide, slippage or settlement and the proposed development can
be constructed without similar adverse impact on adjoining
properties. Obtaining these goals will require good construction
practices and following the recommendations of the project soils
engineer when final plans become available.
NEW COMPACTED FILL
KEYWAY
A keyway was placed at the toe of the fill slope. The key was
approximately 260 feet in length and varied in width from 35 feet
in the northern half of the key to 15 feet at the southern end.
The key was bottomed at least 2 feet into firm underlying
materials.
FILL PLACEMENT
On -site soils were used to construct the fill. The on -site soils
consisted of reddish brown silty clays with sand and rock
fragments.
The fill material was placed in 6 to 8 inch lifts, watered to above
optimum moisture content, and compacted to a minimum of 90 percent
of the laboratory standard.
The maximum depth of fill for this report is approximately 51 feet.
Equipment used in placing and compacting the fill consisted of
track loaders and watering equipment.
Project No. 4-1629-10 Page 5
The maximum density/optimum moisture of the fill soils was
determined in accordance with ASTM:D-1557. Results of the tests
are tabulated on the enclosed "Laboratory Test Results".
DIRECT SHEAR TEST
In order to determine the shearing strength of the on -site soils,
a direct shear test was performed on a representative sample
remolded to 90 percent of the maximum density. To simulate
possible adverse field conditions, the sample was saturated prior
to shearing. A graphic summary of the test results is attached.
EXPANSIVENESS
An expansion test was performed on a typical sample of the material
obtained at foundation level. The sample was tested in accordance
with U.B.C. Standard 29-2 under a surcharge of 144 lbs/sq.ft. The
following result was obtained:
Sample Expansion Potential
Depth (ft.) Soil Type Index Expansion
Finish grade Silty Clay 63 Medium
CONCLUSIONS
All compaction was accomplished in accordance with A.G.I.
Geotechnical, Inc. recommendations. At the locations and
elevations tested by us, the fill was compacted to at least 90
percent of the maximum density as recommended. The completed
subgrade condition of the graded areas approved in this report is
consistent with accepted industry standards.
Project No. 4-1629-10 Page 6
In providing professional geotechnical observations and testing
services associated with the development of this project, we have
employed accepted engineering and testing procedures and have made
every reasonable effort to ascertain that the soil related work was
carried out in general compliance with the project plans and
specifications. Although our observations did not reveal obvious
deficiencies, we do not guarantee the contractor's work, nor do the
services performed by our firm relieve the contractor of
responsibility in the event of subsequently discovered defects in
his work.
We appreciate this opportunity to be of service. If you have any
questions, please do not hesitate to contact this office.
Respectfully submitted,
A.G.I. GEOTECHNICAL, INC.
Enclosures:
Plot Plan
Compaction Test Results
Laboratory Test Results
Results of Shearing Strength Tests
Engineer's Certificate
Distribution: (6) Del Amo Savings
COMPACTION TEST RESULTS
PROJECT NO, 4-1629-10
Test
No.
, DATE
Elevation/ Moisture Unit Dry Relative Soil
Date Depth BelowContent Density Compaction Type
Finish Grade (�) (Lbs.iCu. Ft.) (%) yp
(FL)
1 08/23/94 757.0 15.2 97 107 1
2 08/23/94 757.0 18.6 92 102 1
3 08/23/94 757.0 19.5 91 101 1
4 08/23/94 757.0 15.0 93 103 1
5 08/23/94 757.0 16.5 93 103 1 Sand Cone
6 08/23/94 757.0 17.9 92 102 1
7 08/23/94 757.0 17.1 94 103 1
8 08/23/94 757.0 19.1 92 102 1
9 08/23/94 757.0 15.7 95 104 1
10 08/23/94 757.0 15.9 91 101 1 Sand Cone
11 08/23/94 757.0 14.9 94 103 1
12 08/23/94 757.0 16.2 95 104 1
13 08/26/94 759.0 27.5 84 93 1
14 08/29/94 759.0 22.3 93 96 2
15 08/29/94 759.0 25.3 88 97 1 Sand Cone
16 08/29/94 759.0 22.3 90 93 2
17 08/30/94 760.0 26.5 92 95 2
18 08/30/94 761.0 29.2 88 97 1
19 08/31/94 761.0 27.4 89 98 1
20 08/31/94 761.0 25.3 90 93 2 Sand Cone
21 08/31/94 762.0 27.0 88 97 1
22 08/31/94 762.0 26.5 88 97 1
23 09/01/94 764.0 26.2 91 94 2
24 09/01/94 763.0 26.8 88 91 2
25 09/01/94 763.0 21.8 96 99 2 Sand Cone
26 09/01/94 764.0 26.8 89 92 2
27 09/02/94 765.0 28.6 88 97 1
28 09/02/94 765.0 26.6 89 92 2
29 09/02/94 767.0 25.8 90 93 2
30 09/06/94 769.0 28.7 87 95 1 Sand Cone
31 09/06/94 768.0 28.6 90 93 2
32 09/06/94 767.0 29.0 89 92 2
33 09/06/94 768.0 26.9 91 94 2
34 09/06/94 768.0 28.5 89 98 1
35 09/07/94 769.0 26.4 87 96 1 Sand Cone
36 09/07/94 769.0 27.3 88 97 1
37 09/07/94 769.0 26.6 88 97 1
38 09/07/94 770.0 24.9 92 95 2
39 09/08/94 770.0 19.4 96 96 4 Sand Cone
40 09/08/94 771.0 24.6 99 99 4 Sand Cone
12/14/94
Remarks
A.G.I. GEOTECHNICAL, INC.
COMPACTION TEST RESULTS
PROJECT NO. 4-1629-10 DATE
/
Test DepthatioBelow Moisture Unit Dry Relative Soil
No. Date Finish Grade Content Density Compaction Type
(Ft.) (%) (Lbs./Cu. Ft.) (%)
12/14/94
Remarks
41 09/09/94 770.0 22.4 98 98 4 Sand Cone
42 09/09/94 771.0 23.1 94 94 4 Sand Cone
43 09/09/94 771.0 23.2 91 94 2 Sand Cone
44 09/14/94 772.0 20.4 91 94 2
45 09/14/94 773.0 21.1 90 93 2
46 09/14/94 773.5 20.9 92 95 2
47 09/14/94 772.0 22.1 91 94 2
48 09/14/94 774.0 20.3 91 94 2 Sand Cone
49 09/14/94 774.0 19.4 90 93 2
50 09/14/94 774.0 15.2 94 97 2
51 09/15/94 775.0 25.3 93 96 2
52 09/15/94 775.0 24.6 93 96 2
53 09/19/94 776.0 22.6 93 96 2 Sand Cone
54 09/19/94 776.0 24.0 91 93 3
55 09/20/94 776.0 25.0 91 93 3
56 09/20/94 776.0 25.8 89 91 3
57 09/22/94 778.0 24.0 92 94 3
58 09/22/94 778.0 24.1 92 94 3 Sand Cone
59 09/22/94 778.0 25.0 94 96 3
60 09/29/94 780.0 25.1 93 95 3
61 09/29/94 780.0 23.6 95 97 3
62 09/30/94 780.0 26.7 90 92 3
63 09/30/94 780.0 25.2 92 94 3 Sand Cone
64 10/06/94 781.5 22.5 91 93 3
65 10/06/94 782.0 22.9 92 94 3
66 10/06/94 782.0 22.2 91 93 3
67 10/06/94 782.0 23.8 91 93 3
68 10/12/94 784.0 28.6 85 96 5 Sand Cone
69 10/12/94 784.0 26.7 87 98 5
70 10/12/94 784.0 26.6 87 98 5
71 10/12/94 784.0 28.6 86 97 5
72 10/13/94 785.0 26.0 89 100 5
73 10/13/94 785.0 24.5 91 93 3 Sand Cone
74 10/13/94 787.0 25.3 90 92 3
75 10/18/94 787.0 25.5 93 95 3
76 10/18/94 787.0 25.0 95 97 3
77 10/18/94 787.0 24.1 95 97 3
78 10/20/94 789.0 24.7 94 96 3 Sand Cone
79 10/20/94 789.0 23.8 95 97 3
80 10/20/94 790.0 26.0 93 95 3
A.G.I. GEOTECHNICAL, INC.
COMPACTION TEST RESULTS
PROJECT NO.
Test
No.
Date
81 10/20/94
82 10/20/94
83 10/27/94
84 10/27/94
85 10/27/94
86 10/31/94
87 10/31/94
88 11/01/94
89 11/01/94
90 11/07/94
91 11/07/94
92 11/07/94
93 11/14/94
94 11/14/94
95 11/14/94
96 11/17/94
97 11/17/94
98 11/17/94
99 11/21/94
100 11/21/94
101 11/21/94
102 11/22/94
103 11/22/94
104 11/22/94
Elevation/
Depth Below
Finish Grade
(Ft.)
791.0
791.0
793.0
793.0
793.0
795.0
795.0
796.0
796.0
798.0
798.0
798.0
800.0
800.0
802.0
803.0
803.0
805.0
808.5
806.0
804.0
Slope Face
Slope Face
Slope Face
4-1629-10
Moisture
Content
(%)
Unit Dry Relative
Density Compaction
(Lbs./Cu. Ft.) (%)
24.4 95
25.6 94
24.7 92
24.9 92
24.8 92
23.2 94
23.8 93
23.3 92
24.0 92
23.1 93
23.2 93
23.2 93
25.1 92
23.3 94
21.8 95
24.9 95
25.8 93
25.3 93
21.3 96
22.4 96
23.2 94
22.4 95
23.2 95
24.5 93
DATE
Soil
Type
12/14/94
Remarks
97 3
96 3
94 3 Sand Cone
94 3
94 3
96 3
95 3
94 3 Sand Cone
94 3
95 3
95 3
95 3
94 3 Sand Cone
96 3
97 3
97 3
95 3
95 3 Sand Cone
98 3
98 3
96 3
97 3
97 3 Sand Cone
95 3
A.G.I. GEOTECHNICAL. INC.
LABORATORY TEST RESULTS
PROJECT NO.
4-1629-10 DATE 12/14/94
Soil Maximum Optimum
Classification Density Moisture
Type (Lbs.iCu. Ft.) (%)
1. Brown silty very fine sand (diatomaceous). 90.5 26.0
2. Red brown very fine, silty clay. 97.0 19.5
3. Brown very fine sand, silty clay with rock fragments. 98.0 22.2
4. Dark gray brown silty clay (topsoil). 100.5 16.0
5. Light brown very silty clay. 89.0 29.0
A.G.!. GEOTECHNICAL, INC.
0
1000
2000
3000
4000
5000
6000
7000
0
RESULT OF SHEARING STRENGTH TESTS
Undisturbed, Saturated Samples
SHEARING STRENGTH (LBS/SQ FT)
1000 2000 3000 4000 5000 6000
w = 31.1%
w= Moisture Content at Time of Shearing
B-2 @ 10'
= 22° Ultimate
c = 1600 )sf
w = 32.0%
PROJECT NO.
4-1629-10
A.G.I. GEOTECHNICAL, INC.
0
1000
2000
3000
4000
5000
6000
7000
0
RESULT OF SHEARING STRENGTH TESTS
Undisturbed, Saturated Samples
SHEARING STRENGTH (LBS/SQ FT)
1000 2000 3000 4000 5000 6000
B-2 @ 25' _
= 16, Ultimate
c = 102E psf
w = 32 .6%
w = 33.9%
w=30.(%
w= Moisture Content at Time of Shearing
PROJECT NO.
4-1629-10
A.G.I. GEOTECHNICAL, INC.
0
0
1000
2000 \ "3
3000
4000
5000
6000
7000
RESULT OF SHEARING STRENGTH TESTS
Undisturbed, Saturated Samples
SHEARING STRENGTH (LBS/SQ FT)
1000 2000 3000 4000 5000 6000
\
W = 33.5%
w= Moisture Content at Time of Shearing
B-3 @ 10'
= 29° Ultimate
C = 900 isf
PROJECT NO.
4-1629-10
A.G.I. GEOTECHNICAL, INC.
0
0
1000
2000
3000
4000
5000
6000
7000
RESULT OF SHEARING STRENGTH TESTS
Bulk Samples Remolded To 90% And Saturated
SHEARING STRENGTH (LBS/SQ FT)
1000 2000 3000 4000 5000 6000
Nev Compacted Fill
23` Ultimate
c = 60C psf
PROJECT NO. 4-1629-10
A.G.!. GEOTECHNICAL, INC.
@g. 4/2 03 09:23 7607499412 WYNN ENGINEERING INC
nor U3 0 7 : 38p IV
Winn 31.06 2129
MAR-27-03 17,23 FROM. 10.
PAGE 02
p.2
PACs 1/2
SUMMARY
$AO/SAGEBRUSH LANE LANDSLIDE STABILIZATION PROJECT
Barbara 0. Courtois USFWS Permit #844032-I
PURPOSE;
Presence/absence surveys and possible nest monitoring for California gnatcatcher
Potioptila callfornioa coal jornica (CAGN) for Wynn Engineering. Inc. on approximately
five acres of property that is proposed for landslide stabilization and revegetation with
native plants. The property consists of two adjacent lots, 5 Sagebrush Lane contains a
residence, the other, 6 Sagebrush Lane is vacant.
SURVEY LOCATION:
The Hao/Sagebrush Lane site (hereafter referred to as the site) is located in the City of
Rolling Hills, Los Angeles County, California. It is located west of Portuguese Bend
Road, south of Saddleback Road, east of Sepulveda Canyon and north of Appaloosa
Lane. It is depicted on the Torrance 7.5 quadrangle U.S. Geological Survey topographic
map. Elevation ranged from 700 feet to 830 feet.
METHODS:
Dazes of survey: March 12, I4, 18 and 26, 2003.
Start times: 07:35, 07:10, 07:20 and 07:25 hours.
Finish times: 09:40, 08:40, 08:35 and 08:50 hours.
Temperatures were from 617 to 707 when starting and 62°F to 76°F when finishing.
Wind speeds were from 0 rn/h to I5 mill when starting and 2 RA to 20 m/h when
finishing.
Cloud cover ranged from 0% to 100% when starting and when finishing.
All survey work was done in accordance with the USFWS Carlsbad Office CAGN
protocol. One recorded sequence of 14 calls of California gnatcatcher vocalizations was
played approximately every five minutes when the surveyor was in Coastal Sage Scrub
(CSS) plant communities to elicit responses from CAGNs. The intervening time was
spent listening for CAGN vocalizations, tooling for CAGNs and moving to the next area.
Since the surveys were done during the nesting season for CAGNs if any target birds
were discovered, they would be monitored to determine nesting status.
A somewhat compressed survey was done due to the urgency of the situation and the
dates of the surveys were approved in a telephone conversation between Ms. Kerni Davis
and the surveyor on March 18, 2003.
The same route was not taken during the four surveys. It was initially thought that the
whole survey could be done from the trail (Si's Trail) starting at Appaloosa Lane and
following Sepulveda Canyon. On March 12 it was learned that the trail west of the
residence was completely covered by soil and downed vegetation from the landslide. The
unstable condition of the canyon wall made cross country access impossible. So, the site
was accessed from the above mentioned trail, the Clif Hix trail on the west side of and on
the floor of Sepulveda Canyon and from the perimeter of the residence at 5 Sagebrush
041,p4I 2903 09:23 7607499412
Mar 27 03 07:3ep Ce. Wwrtn
MAR-27-03 17•29 PROM,
WYNN ENGINEERING INC
31411/as 212E
1D.
Lane. Unfortunately this required backtraddng on both trails and some driving and
hiking off the site. It is estimated that no more than 30 minutes each survey day were
spent hiking and driving off the site. All areas of CSS plant communities on site were
covered during each survey period. The initial survey was started at Appaloosa Lane,
continued from the Clif Hix trail and finished at the 5 Sagebrush Lane residence. The
second survey was started at Appaloosa Lane, continued at the Sagebrush Lane residence
and ended at the Clif Hix trail. The third and fourth surveys were started at the Clif Hix
trail, continued at Sagebrush Lane and finished at Appaloosa Lane.
PAGE 03
p.3
PAGE 2,2
'VEGETATION COMMi1NITiES ON SITE:
The site is on the rest side of a predominantly north/south running canyon. The site
contains one residence surrounded by poor quality Coastal Sage Scrub, a graded area
covered by black plastic, disturbed grassland and ruderal plant species and a riparian area
in the bottom of the canyon. Some standing water was noted on the canyon floor.
Plants noted on the site were California sagebrush (Artemisia c alrfornica) California
bvshsunflower (Encelia californfca), lemonade betty (Rbrrs integrifolia), Mexican
elderberry (Sarrrbucus mender), California buckwheat (Eriogonum fascieulalum),
purple Sage (Salvia leuer>phylla) and laurel sumac (Rhris lamina), poison oak
(Toxicodendron diversiloba), wild cucumber (Man h mauocmpffs), California
blackberry (Rebus ursinvs), Canary Island pine, (Pinus eancrlensis), castor bean (R icinis
cornmunis), tree tobacco (Nicoltana glar.eca), ashy -leaf buckwheat (Eriogomarr cinereum),
Peruvian peppernreee, (Sciu'mts molle), arroyo willow (Sake lasiolepis), succulent lupine
(Luplhus succulentus), date palm sp. and Mulefat (I3acchr fs salicifolia). Other
vegetation species were present, but time was not taken to seek them out or key them
since a separate vegetation survey had been done previously.
RESULTS:
No California gnatcatchets, Polioptila culifomica cabf» nka were found on the site.
Alien's hummingbird
American crow
Bewick's wren
Busbtits
California towhee
Common raven
Fox spatsaw
Hermit thrush
House finch
Northern mockingbird
Orange -crowned warbler
Red -shouldered bawk
Red-tailed hawk
Ruby -crowned kinglet
Sharp -shinned hawk
Spotted towhee
Western scrub jay
Bird Species Seen On Site
Salaspharus sosin
Corms brachyrhyrrchos
Thryomones bewfckif
Psaltrf punts Mirntmus
P:pifo crirsalis
Corvus comic
Passerslla ilirrrrr
Caifrarus grrrlatus
Carpodacstr maces
Mfmus polygtonos
Vernrivora celata
Bump lirreotus
Bureo,jcnwiceinis
Regulus calertdrela
Fake spurverius
Plpilo macularus
Aphelocoma californica
ENVIRONMENTAL ANALYSIS FORM
DATE:
PROJECT NAME:
PROJECT NUMBER(S):
EXPLANATION OF ANSWERS:
November 26, 2002
Hao Landslide Repair
#5 Sagebrush Lane, Rolling Hills
Zoning Case #632
The following questions are answered either "Potentially Significant Impact", "Less Than
Significant With Mitigation Incorporation", "Less Than Significant Impact", or "No
Impact" and are defined as follows.
"Potentially Significant Impact." The applicant is of the opinion there is substantial
evidence that the project has a potentially significant environmental effect and the effect
is not clearly avoidable with mitigation measures or feasible project changes.
"Potentially Significant Impact" means that the applicant recommends the preparation of
an Environmental Impact Report (EIR) for the project.
"Less Than Significant With Mitigation Incorporation." The applicant is of the
opinion there is substantial evidence that the project may have a potentially significant
adverse effect on the resource. However, the incorporation of mitigation measures or
project changes agreed to by the applicant has clearly reduced the effect to a less than
significant level.
"Less Than Significant Impact." The applicant is of the opinion that the project may
have an effect on the resource, but there is no substantial evidence that the effect is
potentially significant and/or adverse.
"No Impact." The applicant is of the opinion that, as a result of the nature of the project
or the existing environment, there is no potential for the proposed project to have an
effect on the resource.
I.
AESTHETICS
a) Would the project have a substantial adverse effect on a scenic vista?
Less Than Significant Impact
This would be a temporary impact. Failure to promptly repair the
landslide would lengthen time of temporary impact.
• •
b) Would the project substantially damage scenic resources, including but not
limited to, trees, rock outcroppings, and historic buildings within a state
scenic highway?
Less Than Significant Impact
Rock outcroppings may be temporarily impacted, but site will be safer
after grading is completed.
c) Would the project substantially degrade the existing visual character or
quality of the site and its surroundings?
Less Than Significant With Mitigation Incorporation
Only on a temporary basis during grading. Revegetation (in -kind) of
native habitat is proposed after grading.
II. AGRICULTURE RESOURCES
In determining whether impacts to agricultural resources are significant
environmental effects, lead agencies may refer to the California Agricultural Land
Evaluation and Site Assessment Model (1997) prepared by the California Dept. of
Conservation as an optional model to use in assessing impacts on agriculture and
farmland.
NO IMPACT
III. AIR QUALITY
Where available, the significance criteria established by the applicable air quality
management or air pollution control district may be relied upon to make the
following determinations.
a) Would the project conflict with or obstruct implementation of the
applicable air quality plan?
Less Than Significant With Mitigation Incorporation
Standard grading dust control measures will be implemented into grading
plan specifications.
• •
b) Would the project violate any air quality standard or contribute
substantially to an existing or projected air quality violation?
Less Than Significant With Mitigation Incorporation
Same as a) above.
c) Would the project result in a cumulatively considerable net increase of any
criteria pollutant for which the project region is non -attainment under an
applicable federal or state ambient air quality standard (including releasing
emissions, which exceed quantitative thresholds for ozone precursors?
Less Than Significant With Mitigation Incorporation
Same as a) above.
d) Would the project expose sensitive receptors to substantial pollutant
concentrations?
Less Than Significant Impact
Same as a) above.
e) Would the project create objectionable odors affecting a substantial
number of people?
Less Than Significant Impact
Same as a) above.
IV. BIOLOGICAL RESOURCES
a) Would the project have a substantial adverse effect, either directly or
through habitat modifications, on any species identified as a candidate,
sensitive, or special status species in local or regional plans, policies, or
regulations, or by the California Department of Fish and Game or U.S.
Fish and Wildlife Service?
Less Than Significant With Mitigation Incorporation
Careful biological mapping has recently been performed The limits of
grading are dictated by the geology and limits of the landslide feature. A
revegetation plan will be proposed to the local jurisdiction for review and
approval. See attached biology report dated September 10, 2002.
• •
b) Would the project have substantial adverse effect on any riparian habitat
or other sensitive natural community identified in local or regional plans,
policies, regulations or by the California Department of Fish and Game or
U.S. Fish and Wildlife Service?
Less Than Significant With Mitigation Incorporation
Same as a) above.
c) Would the project have a substantial adverse effect on federally protected
wetlands as defined by Section 404 of the Clean Water Act (including, but
not limited to, marsh, vernal pool, coastal, etc.) through direct removal,
filling, hydrological interruption, or other means?
Less Than Significant Impact
The soil in some of the watercourse will be removed, replaced and
revegetated in kind. See a) above.
d) Would the project interfere substantially with the movement of any native
resident or migratory fish or wildlife species or with established native
resident or migratory wildlife corridors, or impede the use of native
wildlife nursery sites?
Less Than Significant Impact
Any species corridors will be reestablished after remedial grading is
completed and slopes are replanted. Fire buffers will be honored. See a)
above.
f) Would the project conflict with the provisions of an adopted Habitat
Conservation Plan, Natural Community Conservation Plan, or other
approved local, regional, or state habitat conservation plan?
Less Than Significant With Mitigation Incorporation
Same as a) above.
• •
V. CULTURAL RESOURCES
c) Would the project directly or indirectly destroy a unique paleontological
resource or site or unique geologic feature?
Less Than Significant With Mitigation Incorporation
A landslide will remove and replace with a buttress fill. Careful
geotechnical supervision will be required
VI. GEOLOGY AND SOILS
a) Would the project expose people or structures to potential substantial
adverse effects, including the risk of loss, injury, or death involving:
i) Rupture of known earthquake fault, as delineated on the most
recent Alquist-Priolo Earthquake Fault Zoning Map issued by the
State Geologist for the area or based on other substantial evidence
of a known fault? Refer to Division of Mines and Geology Special
Publication 42.
NO IMPACT
ii) Strong seismic ground shaking?
Less Than Significant Impact
Vibration from grading may shake structure. Underpinning
already in place should support structure. Cosmetic repairs may
be necessary.
iii) Seismic -related ground failure, including liquefaction?
NO IMPACT
iv) Landslides?
Potentially Significant Impact
In this case, prompt repair will have a "positive" significant
impact, not requiring an Environmental Impact Report.
• •
b) Would the project result in substantial soil erosion or the loss of topsoil?
Less Than Significant With Mitigation Incorporation
Proper Storm Water Pollution Prevention measures; erosion control and
revegetation will mitigate this impact.
c) Would the project be located on a geologic unit or soil that is unstable, or
that would become unstable as a result of the project, and potentially result
in on-. Or off -site landslide, lateral spreading, subsidence, liquefaction or
collapse?
Potentially Significant Impact
Intensive geotechnical review and supervision as well as proper
underpinning of structure will mitigate this potentially significant impact.
No Environmental Impact Report. should be required beyond engineering
studies.
d) Would the project be located on expansive soil, as defined in Table 18-1B
of the Uniform Building Code (1994), creating substantial risks to life and
property?
Potentially Significant Impact
Same as c) above.
e) Would the project have soils incapable of adequately supporting the use of
septic tanks or alternative wastewater disposal systems where sewers are
not available for the disposal of wastewater?
Less Than Significant Impact
Existing seepage pit will be evaluated after grading.
VII. HAZARDS AND HAZARDOUS MATERIALS
a) Would the project create a significant hazard to the public or the
environment through the routine transport, use, or disposal of hazardous
materials?
Less Than Significant Impact
No hazardous materials are known. If any are discovered during grading,
mitigation will be proposed if/as encountered.
•
b) Would the project create a significant hazard to the public or the
environment through reasonably foreseeable upset and accident conditions
involving the release of hazardous materials into the environment?
Less Than Significant Impact
Same as a) above.
VIII. HYDROLOGY AND WATER QUALITY
a) Would the project violate any water quality standards or waste discharge
requirements?
Less Than Significant With Mitigation Incorporation
Summer grading is proposed A Storm Water Pollution Prevention Plan.
will be designed and implemented if/as required
c) Would the project substantially alter the existing drainage pattern of the
site or areas including through the alteration of the course of a stream or
river, in a manner which would result in substantial erosion or siltation on -
or off -site?
Less Than Significant With Mitigation Incorporation
Streambed will be altered temporarily during grading.
d) Would the project substantially alter the existing drainage pattern of the
site or areas including through the alteration of the course of a stream or
river, in a manner which would result in flooding on- or off -site?
j)
Less Than Significant Impact
Same as a) above.
Inundation by seiche, tsunami, or mudflow?
Less Than Significant Impact
Same as a) above.
• •
IX. LAND USE AND PLANNING
b) Would the project conflict with any applicable land use plan, policy, or
regulation of an agency with jurisdiction over the project (including but
not limited to the general plan, specific plan, local coastal program, or
zoning ordinance) adopted for the purpose of avoiding or mitigating an
environmental effect?
Less Than Significant Impact
Several variances are requested and justified in the individual
applications.
c) Would the project conflict with any applicable habitat conservation plan or
natural community conservation plan?
Less Than Significant With Mitigation Incorporation
Careful biological mapping has recently been performed. The limits of
grading are dictated by the geology and limits of the landslide features. A
revegetation plan will be proposed to the local jurisdiction for review and
approval.
X. MINERAL RESOURCES
a) Would the project result in the loss of availability of a known mineral
resource that would be of value to the region and the residents of the state?
Less Than Significant Impact
The Storm Water Pollution Prevention Plan will minimize siltation.
b) Would the project result in the loss of availability of a locally important
mineral resource recovery site delineated on a local general plan, specific
plan or other land use plan?
Less Than Significant Impact
Same as a) above.
• •
XL NOISE
a) Would the project result in exposure of persons to or generation of noise
levels in excess of standards established in the local general plan or noise
ordinance, or applicable standards of other agencies?
Less Than Significant With Mitigation Incorporation
The grading operation will generate noise during city allowed
construction hours.
b) Would the project result in exposure of persons to or generation of
excessive groundborne vibration or groundborne noise levels?
Less Than Significant With Mitigation Incorporation
Same as a) above.
d) Would the project result in a substantial temporary or periodic increase in
ambient noise levels in the project vicinity above levels existing without
the project?
Less Than Significant With Mitigation Incorporation
Same as a) above.
XII. POPULATION AND HOUSING
NO IMPACT
XIII. PUBLIC SERVICES
NO IMPACT
XIV. RECREATION
a) Would the project increase the use of existing neighborhood and regional
parks or other recreational facilities such that substantial physical
deterioration of the facility would occur or be accelerated?
Less Than Significant Impact
Equestrian trail to be restored after grading.
• •
b) Does the project include recreational facilities or require the construction
or expansion of recreational facilities, which might have an adverse
physical effect on the environment?
Less Than Significant Impact
Same as a) above.
XV. TRANSPORTATION/TRAFFIC
a) Would the project cause an increase in traffic which is substantial in
relation to the existing traffic load ad capacity of the street system (i.e.,
result in a substantial increase in either the number of vehicle trips, the
volume to capacity ratio on roads, or congestion at intersections?
Less Than Significant With Mitigation Incorporation
Soil import is required per geotechnical studies. Import can be controlled
during certain hours.
b) Would the project exceed either individually or cumulatively, a level of
service standard established by the county congestion management agency
for designated roads or highways?
Less Than Significant With Mitigation Incorporation
Same as a) above.
e) Would the project result in inadequate emergency access?
Less Than Significant Impact
Same as a) above.
f) Would the project result in inadequate parking capacity?
Less Than Significant Impact
Same as a) above.
XVI. UTILITIES AND SERVICE SYSTEMS
c) Would the project require or result in the construction of new stormwater
drainage facilities or expansion of existing facilities, the construction of
which could cause significant environmental effects?
• i
Less Than Significant Impact
Final design may incorporate new culverts at equestrian trails.
XVII. MANDATORY FINDINGS OF SIGNIFICANCE
a) Does the project have the potential to degrade the quality of the
environment, substantially reduce the habitat of a fish or wildlife species,
cause a fish or wildlife population to drop below self-sustaining levels,
threaten to eliminate a plant or animal community, reduce the number or
restrict the range of a rare or endangered plant or animal or eliminate
important examples of the major periods of California history or
prehistory?
Less Than Significant Impact
Careful grading supervision and revegetation as described above will
restore stability to the site and restore the habitat for the plant and animal
community.
b) Does the project have impacts that are individually limited, but
cumulatively considerable? ("Cumulatively considerable" means that the
incremental effects of a project are considerable when viewed in
connection with the effects of past projects, the effects of other current
projects and the effects of probable future projects.)
Less Than Significant With Mitigation Incorporation
The grading is necessary to restore stability of the residential site. All
impacts will be temporary.
c) Does the project have environmental effects, which will cause substantial
adverse effects on human beings, either directly or indirectly?
Less Than Significant With Mitigation Incorporation
Incorporation of the mitigation measures with close engineering
supervision will offset the potential Impacts.
Prepared b
J
Gary ynn, P.E.
President
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Sheet of 2
REVIEWER CAILiNG HOURS
8-9 a.m. & 3-4 p,m. Mon.-Ztturs.
•
County of Los Angeles Department of Public Works
GEOTECHNICAL AND MATERIALS ENGINEERING'D1VIS ON F X NF
GEOLOGIC REVIEW SHEET
Tract 30345
Parent Tract
Site Address 5 & S aggpbrush Lane
Geologist Gait Hunt
Soils Engineer Date Hinkle
900 S. Fremont Ave., Alhambra, CA 91803
TEL (626) 458-4925
Lot 3 & 4
Location City of Rolling Hills
Developer/Owner Hao
Engineer/Arch. Wynn
Review of:
Grading P.C. No, _Qg10240003 For: , Remedial oradingwith installation of buttress fill
Geologic Report(s) Dated __
Soils Engineering Report(s) Dated ----------
Geology and Soils Engineering Report Dated 10/07/02, 5/10/01
Action: Plan is not recommended for approval for reasons below.
Remarks/Conditions:
Dist. Office 12,02
e-mail: kvazquezeladpw.org
DISTRIBUTION
2 Dist. Office
Geologist
.. Soils Engr.
Section File
Grading Sect.
�.- Proc. Ctr.
1. As requested in prior Geologic and Soils Engineering Review Sheet dated 2/22/01, an Geologic revlew3:dated 6/11/01and
9/24/01, provide a geologic map and geologic cross sections based on a current gr Iding plan that is based on existing
topography and clearly depicts the proposed mitigation of the existing landslides. Al relevant geologic and geotechnical
information should be transferred to the current topographic map/grading plan. The grading 'plans submitted must be
complete (all notes and details, etc. per Chapter 33 of the County of Los Angeles Buildin I Code, and requirements of Building
and Safety Division).
•
2. Add all relevant geologic units and structural data to the geologic map. Add all relevant symbols to the Explanation. Only show
on the map and explanation the units and symbols represented on site.
3. The topographic profiles depicted on geologic cross -sections must be revised to shot ' the existing, topography of the site.
Please also label existing caissons at 5 Sagebrush so that they may be more easily referenced. Aftfo indicate who logged
Borings B1, B2, and B7, include the reference and copies of the logs if they are not cont4ined in any of the previous reports.
4. In order to accurately characterize the active landslide for slope stability analysis•purposi
of the active landslide must be utilized for the slope stability analyses that transect the to
s the current topographic expression
dstide (1.1', 2-2', 3-3', and Z-Z').
5. Provide the data and analyses used to make the determination stated in the last paragrapph on page 4, and In the 1°1 paragraph
on page 5. NOTE: All conclusions and recommendations provided must be based on actual supporting data..Deterihine the
upper boundary of the "ancient" landslide Clots, or assume a worst -case upper boundary for utilization in.the stability analyses.
Provide stability analyses utilizing shear strength data obtained from slide plane material (Boring B-21s 0 65-68').
6. Extend geologic cross sections 4-4' and Z-Z' to Include the entire south and south-eaAward extent of landslide Ools. The
entire length of these sections must be considered in the stability analyses.
7. There appears to be some discrepancy in the Interpretation of the geometry of the active -landslide.
The report states that active landaliding movement is occurring along the base of the '-ancient" landslide, however, this has
only boon depicted on cross-section 1-1'. Also, cross -sections 2-2' and 3-3' show the pitons of the active landslide as relatively
straight, whereas, cross -sections 1-1' and Z-Z' show much more curvature of tho'.slide lane. All four cross -sections should
show a similar geometry considering their relative positions.
•
Since it has not been stated explicitly in the report that the active landslide is to be'comeletely removed (with the exception of
a statement to the effect that slide -affected materials will be removed, which couldappha to the entire site, or depicted an the
grading plan) It is important to establish the geometry of the active landslide as concluslt.ely as possible.
8. Provide the back -calculation mentioned on page 5 (1017/02), and/or provide its location i l the 5/10/01 report.
9. On page 10 it is stated that "The proposed house structures should all be located on the I 'ut pad area of the. site " And on page
12 it Is stated that "...all foundations will be founded in compacted fill pad (sic) or bedrock " Please reconcilethese statements.
10. Provide recommendations for subdrainage of the remedial grading and depict notes and details on the grading plans.
11. On page 7. 1" paragraph It Is recommended to construct a stabilization fill within a recorded "Flood Hazard" easement.
. Determine if grading will be•permltted In this area and if not, provide alternate recomme aeons and depict on the plans.
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Page 4/7
feet 2,of.2
The limits of the buttress key shown on the Preliminary Grading Plan does not match the lirr'its shown on Figure 8 (Buttress
Design Plan), which was used to construct the geotechnical cross -sections. These plans should be identical for the purpose
of global stability analysis of the buttress fill. All geotechnical cross -sections should be upeated and should be overlain on
the geologic cross -sections to show the relative position of the active landslide to the buttress; but not until the geometry of the
active landslide has been more conclusively determined. Also note that section Y-Y' is not shown on the geotechnlcal map
or provided In the report but there are elope stability analyses utilizing this cross-sectiori.
3. In the report it Is stated that along the unnamed gully, located on the east side of Lot 4,:there s a slight component of bedding
Into the gully, please clarify what is meant by this and show any bedding attitudes obtained luring mapping on the geologic
map. Please clarify If this the area to receive the referenced stabilization fill and show this onithe grading plan.
et. The report should be edited for grammatical, typographical, and factual errors. The foilowinc are some of the most egregious
examples; please verify and correct as necessary:
Page 1: Paragraph 1 states "Lot 2 was not drilled..." (Borings B-31s and B-41s are shown on lr.t 2)
Page 2: 1" sentence appears to be incomplete, or contains an unneeded "and"
Page 2: 7d' paragraph states "boring 1 was drilled —at 5 sagebrush Lane" (Boring 1ls is.show i on Lot 4, #i6 Sagebrush)
Page 7:1°t sentence states "...east side of lot 6" (Lot 4, #6 Sagebrush Lane?)
Page 8: summary of slope stability analyses, #2 Section E-E' 75" key (75'?)
Page 11: 4°5 paragraph refers to "311 statement"
Throughout report, apparent confusion between address and lot numbers: suggest using onl one point of reference.
5. The 111 statement contained in the report (referred to as 311(?) on pg. 11) should be modified to specifically address the
safety of the existing home at #5 Sagebrush against hazard from future landsliiding. settirment or slippage during grading
operations and a finding regarding the effect that the proposed grading construction will gave' on the geologic stability of
property outside of the building site. The finding must be substantiated by appropriate: data and analysis.
16. The consultants recommend that the grading of Lot 3 be performed with 100-foot wldt slot cuts. however, no grading
construction methods for Lot 4 have been provided. Construction methods for both Lots 3 end 4 must be discussed in detail
and must be approved by the consultants prior to approval of the grading plan.
17. All recommendations of the consulting geologist and soils engineer must be incorporated ilhto the design or shown as notes
on the plans.
18. The plan must be specifically approved by the consultant geologist and soils engineer b , manual, original signatures and
dates on each sheet prior to approval by the Geology Section.
19. Add the following as notes to the plan:
In -grading inspections must be made by the consulting geologist and soils engineer.. Bi-w
must be submitted directly to the Geology and Soils Section by the consultants.
Rough grading must be approved by a final geology and soils engineering report prior to
Section. An As -Built Geologic Map must be included in the final geology report. Submit
building permit. Provide a final report statement that verifies work was done In accordance_
code provisions (per Section 7021-3).
20. The Soils Engineering review dated \?�3l(02Z is attached.
Prepared by /� Reviewed by
Karin az
Charles Nestle
le* in -grading inspection reports
ipproval by the Geology and Soils
'apart for' approval for issuance of
with report recommendations and
Date December 12. 2002_
NOTICE: Public safety, relative to geotecmnkal subsurface exploration, snail be provided !n accordance with currant code : for excavations,
Inclusive of the Los Angeles County Coda, Chapter 11.4a, and the State of California, Title 6, Construction Saf ty'Ordere.
The "Manual for Preparation of aeotechnical Reports" prepared by County of Los Angeles, Department of Public Works Is availarte on the Internet at the tosowing
address: hnp!/dpw.co.fa.ca.us/medlmsnuaf.pdf
D;1Mepubhgeology revienkforms\Form 6
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Page 5/7
Address:
Telephone:
Fax:
Review No. I
COUNTY OF LOS ANGELES
DEPARTMENT OF PUBLIC WORKS
GEOTECHNICAL AND MATERIALS ENGINEERING DIVISION
900 S. Fremont Ave.
Alhambra, CA 91803
(626) 458-4925
(626) 458-4913
SOILS ENGINEERING REVIEW SHEET
Remedial Grading for Slope Repair (Lots 3 and 4)
Grading for Single Family Residence (Lot 3)
Tract 30345 Lots 3 and 4
Location 5 and 6 Sanebrush Lane. City of Rolling Hills
Developer/Owner • Hao •
Engineer/Architect Wynn
Soils Engineer Dale Hinkle
Geologist Gail Hunt
Grading Plan Check No. 0210240003
Review of:
Grading Plan Dated By Processing Center 11/6/02
Solis Engineering and Geologic Report Dated 10/7/02
Previous review sheet dated 10/29/01 (BPC 0105220008 & 9911160003)
ACTION:
Plan is not recommended for approval.
REMARKS:
1. Requirements of the Geology Section are attached.
District Office 12.02
Job No. B372001
Sheet 1 of 3
DISTRIBUTION:
1 Drainage
• I_Grading
1 Geo/Soiis Central File
1 District Engineer
1 Geologist
1 Soils Engineer
1 Engineer/Architect
2. Provide an updated geotechnlcal map and revised cross -sections based: on tire existing topography and the current
grading plans. Also extend Cross -Sections 4-4' and Z-Z' to include the entire nouth and.south-eastward extent of the
landslide es requested by the Geology Section. Provide revised slope stability analyses of the revised and extended
cross -sections as necessary. Recommend mitigation if factors of safety are below County minimum standards.
3. Verify the limits and depth of the active landslide as requested by the Geology Section. Also verify the geometry
(shape) of the active landslide. For example, Figure 9 provided in the 10/77/02 ref ort shows a circular critical facture plane
for Cross -Section 1-1'. However, Figures 10, 11, 12, and 13 In the same repo show a block (wedge) critical failure
plane for Cross -Sections 2-2', 3-3' 4-4`, and .Z-Z' for the same landslide. Povide revised sections es necessary.
Additionai'slope stability analysis may be required when the geology of the site mrrd the potential failure mode (rotational
versus translational) are conclusively determined. •
4. Verify or provide substantiating• data for the following design soil parameters (that were used in the slope stability
analyses) provided on pages 5 and 6 of the 101T102 report
a. Shear strength parameters for the landslide materials along the: critic 1 failure plane for the static condition.
Page 8 of the 10/7/02 report states that these parameters were dete fined from back -calculation provided in
the 5/10/01 report. However, such analyses could not be located in th 5/10/01 report. Provide the necessary
back-calculation'that shows a factor of safety of approximately 1.0,: as n essary.
b. Shear strength parameters for the landslide materials along the critics failure plane for the seismic condiition.
Page 8 of the 10(7/02 report shows a cohesion value of 500 pcf. fi r, most of the analyses provided in the
same report shows that a cohesion value of 150 pcf was used for both a static and seismic conditions. Verify
and revise as necessary.
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COUNTY OF LOS AN.GELES
DEPARTMENT OF PUBLIC WORKS
GEOTECHNiCAL AND MATERIALS ENGINEERING DIVISION
SOILS ENGINEERING REVIEW SHEET
Grading Plan Check No. 0210240003 Sheet 2 of 3
REMARKS (CONT) .
c. Shear strength parameters for the existing fill materials as used for the back -cut analyses. The soils report
shows shear strength parameters that are similar to those of the:prop sed buttress 01 materials compacted
to 90 percent relative compaction. However, the existing fill .materials areas where the proposed back -cut
will be made at the existing caisson locations might have been disturbed That is, the fill in this area• may have
density less than the fill soils that were originally compacted to a .minir►ium 90 percent relative compaction.
in areas where the back -cuts could not be made Into undisturbed•firm materials, shear. strength parameters
representative of disturbed fill materials must be used for analyses of the proposed back -cuts. Therefore, provide
laboratory test results for disturbed fill materials as necessary.
d. Shear strength parameters for the proposed buttress fill materials ` used for the stability. analyses.. The sons
report shows shear strength parameters of W = 30° and c e 200 psf. The laboratory test result sheets provided
in the appendix show shear strength parameters of e e 30° and c.= 17f- psf and p m 35° and c se 50 psf for 2
remolded samples tested respectively. For static, seismic, anQ: surf -cial stability analyses, the controlling
shear strength parameters (i.e., the most conservative values) must be i sed. Verify and.revise as necessary.
5. The geotechnical map provided in the 10/7/02 report shows Cross -Sections 1-1' 2-2', and 3-3' oriented in the direction
of landslide movement, whereas other sections (in which stability analyses were performed) are at an angle to the
direction of landslide movement. Yet no stability analyses were performed:ifor th Ise 3 sections. Provide static, seismic
and surficial slope stability analyses for Cross -Sections 1-1', 2-2', and: 3-3' fiat are in the direction of landslide
movement. Indicate the various shear strength parameters used in the analyse, :, in the appropriate segments of each
failure plane. Recommend mitigation if factors of safety are below County nilnimun standards.
6. Verify or provide substantiating data and analyses for the following numbers and %gures shown inthe `Summary of Slope
Stability Calculations' as provided on page 8 of the 10/7/02 report:
a. A. factor of safety of 1.25 (with caissons) was determined for the prnposew back -cut for.SectioriDD-DD'. Provide
substantiating stability analyses as necessary. Indicate the various. sneer strength parameters used in the
analyses, In the appropriate segments of each failure plane. Recomrr end mitigation if factors of safety are
below County minimum standards.
b. A factor of safety of 1.5 (with caissons) was determined for the:propesed 1:1 back -cut for Section EE-EE'.
Provide substantiating stability analyses as necessary. indicate the various shear strength' parameters used
in the analyses, in the appropriate segments of each failure plane, Re' ommend mitigation If factors•of safety
are below County minimum standards.
c. Factors of safety of 1.33; 1.3, end 125 (without caissons) were deterrrrned for the proposed 40° back -cut for
Sections EE-EE', Z-Z' and 4 4' respectively. However, the printout:for th s analyses for Section•EE-EE' provided
in the 5/10/01 report shows a minimum factor of safety of 1.01. Verify and revise as necessary. Recommend
mitigation if factors of safety are below County minimum standards
d. Factors of safety of 1.11 and 1.21 were determined for the buttress fill slopes under seismic condition for
Sections Z-Z' and 4-4', respectively. However, the printouts for the anaisses for Sections Z-Z' and 4-4' provided
in the 1017/02 report show minimum factors of safety of 1.04 and 1 35, respectively. -Verify and revise as
necessary. Recommend mitigation if factors of safety are below County !minimum standards.
e. A proposed key width of 75" (inches?) for the buttress fill slope for Section EE-EE'. Verify and revise as
necessary.
f. A proposed key width of 140' (feet) for the buttress fill slope for Section --4'. However, Figure 12 of the 10/7/02
report shows a key width of 120 feet Verify and revise as necessary.
7. Provide revised static and seismic slope stability analyses utilizing shear:Strength parameters that are representative
of the conditions noted in Remark 4 of this review sheet. Also provide surficlall slope stability analyses for the proposed
2:1 (with some portions at 1.5:1) buttress fill slopes, considering the low coh salon values of the fill materials (with
cohesion as low as 50 pet) . Indicate the various shear strength parameters'u act in the analyses, In•the appropriate
segments of each failure plane. Recommend mitigation if factors of safety -ere be low County minimum standards.
8. Page 7 of the 10/7/02 report states that some of the stability analyses weremod led with a 3-foot thick (water) saturated
layer above the failure surface, However, both the input data sheet and the. traphical printout sheet provided in the
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COUNTY OF LOS ANGELES
DEPARTMENT OF PUBLIC WORKS • .
GEOTECHNICAL AND MATERIALS ENGINEERING DIVISION
SOILS ENGINEERING REVIEW SHEET
Grading Plan Check No. 0210240003 Sheet 3 of 3
REMARKS (CONT)
S. Page 10 of the 10/7/02 report states that the proposed structures be located on tie cut pad area of the site. However
page 12 of•the same report recommends that all foundations be founded In compacted .fill or bedrock. Per County
policy, all footings for each proposed structure shall be founded on a uniform fo mdation material Verify and provide
revised foundation recommendations as necessary.
10. Page 10 of the 10R/02 report states that the proposed structure at Lot 4 may haves a basement. Provide the Equivalent
Fluid Pressure (EFP) for the design. of the proposed basement walls (restrained ;ondition) and for arty other proposed
retaining walls (unrestrained condition), considering expansive backlit! soils as necessary.
11, Provide expansion test results of the on -site soils. Recommend mitigation as: ilece=nary.
12. Provide resistivity test results for the on -site soils to address the presence Of the ica%s deleterious to ferrous materials.
The tests must be in accordance with California Test Methods, Department of ransportation, or equivalent (aqueous
solution tests, such as EPA Tests or similar methods are not acceptable for termination of resistivity). Resistivity
tests must be performed on soil samples in a saturated condition.
13. The 111 statement provided In the 10R/02 report (stated as 311 in the 10/7102 eport) is Incomplete. The soils report
must also address whether the eidsting home at 5 Sagebrush will be safe aeainst hazard • from 'future landsfding,
settlement or slippage, as a result of the proposed remedial grading. Provider revised 111 statement as necessary.
The finding must be substantiated by appropriate data and analysis.
14. Show the following on the grading plans:
a. Approximate limits and depth of removal and recompaction of slide :debris and unsuitable soils.
b. Revised' limits and extent of the proposed buttress arid key. (Note.that he Omits of the buttress key shown on
the plan does not match the limits shown on Figure 8 of the 10R/02"repor ).
c. Grading required for construction of buttress/stabilization fiilss. •
d. Detail of keying and benching for placement of fill over slopes steeper th 5:1 gradient
e. Location of all back -drains for the proposed buttresses, per the soils •eng eer.
f. , . Location of 100 feet slot cuts for the proposed remedial grading, per the oils engineer.
g. Details of proposed back -cuts (at 40° or flatter) for the proposed .remedia grading, per the soils engineer.
h. All notes regarding till compaction and density testing requirements:
I. Ail recommended mitigative measures of the soils engineer.
16. The Soils Engineer of record must review the grading plans and sign, and ;tamp the plans in verification of his
recommendations. Original manual signature and wet stamp are required.
17. Include a copy of this review sheet with your response.
NOTEIS) TO THE. PLAN CHECKER/BUILDING AND SAFETY DIS
ON -SITE SOILS ARE CORROSIVE TO CONCRETE.
1tared by
Date 12/31 /02
Gan
NOTICE: Public safety, relative to deotechnical subsurface exploration, shall be piovidel In accordance with., current codes for
sa.. f wet Awwad "w„wIU ( tIA r_hnnfse ii an and fh* sates ei Cilllbrnla. Tttte'a. Construction Safaty Orders.