HomeMy WebLinkAbout3188; College Boulevard Extension; College Boulevard Extension Geotechnical Investigation; 1983-11-11SAN DIEGO SOILS ENGINEERING, INC.
SOIL ENGINEERING & ENGINEERING GEOLOGY
November 11, 19 83
The Roll Company
7330 Engineer Road
San Diego, California
Job No. SD1217-00
Log No. SD3-2779
Attention
SUBJECT:
92111
Mr. Steve Mahoney
PRELIMINARY GEOTECHNICAL INVESTIGATION
Proposed College Boulevard Extension
Carlsbad Research Center to Palomar Airport Road
Carlsbad, California
Gentlemen:
In accordance with your request, we have completed a Prelimin-
ary Geotechnical Investigation of the proposed alignment of
College Boulevard between the,Carlsbad Research Center and Palo-
mar Airport Road. The proposed alignment will cross property owned
by the Signal Landmark Company and the Huntington Beach Company.
Our investigation has utilized 40-scale, grading and improvement
plans for "College Boulevard - Carlsbad Research Center" and
100-scale topographic maps prepared by Rick Engineering.
I. IMTROVUCTJOM
The scope of services provided during the preparation of
this Prelim.inary Geotechnical Investigation included:
A. Review of previous geotechnical reports and maps pertinent
to the project area (See Appendix A);
B. Analysis of stereographic aerial photographs to evaluate
the topography and geologic structure of the area (See
Appendix A);
SUBSIDIARY OF IRVINE CONSULTING GROUP, INC.
6455 NANCY RIDGE DRIVE* SUITE 200» SAN DIEGO, CA 92121 •(619)587-0250
The Roll Company . Job No. SD1217-00
November 11, 1983 Log No. SD3-2779
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C. Geologic mapping of existing exposures and outcrops;
D. Subsurface exploration, including six bucket auger bor-
ings to a maximum depth of 64 feet and 17 backhoe test
pits excavated to a maximum depth of 13 feet;
E. Logging and sampling-of exploratory excavations to eval-
uate the geologic structure and to obtain ring and bulk
samples for laboratory testing;
F. Laboratory testing of samples representative of those
obtained during the field investigation;
G. Geologic and soils engineering analyses of field and
laboratory data which provide the basis for our conclu-
sions and recommendations;
H. Preparation of this report and accompanying maps, cross
sections and other graphics presenting our findings, con-
clusions and recommendations.
II. SITE VESCRIVTION
The proposed 0.8 mile College Boulevard extension is planned
to connect the proposed Carlsbad Research Center to the north-
east and Palomar Airport Road to the southwest. The approxi-
mate location and topography are shown on the Location Map,
Figure 1. As depicted on the Geotechnical Map (Plates 1 and
2), the area investigated consisted of a strip up to 700 feet
wide bracketing the centerline of the proposed roadway.
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November 11, 1983 Log No. SD3-2779
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Topographically, the area consists of a dissected mesa with
gently rolling topography at the higher elevations, bounded
by steep slopes and deeply incised drainages. Natural slopes
in the vicinity range from nearly flat to 1.5:1 (horizontal:
vertical). Specifically, the proposed road alignment will
parallel a prominent west to southwest trending ridge. The
northeast and central portions of the road will be located on
a gentle (5:1 to 8:1) north facing slope whereas the remainder
of the road is aligned with the top of the ridge. Maximum
relief on the site is 232 feet with elevations ranging from
89 feet to 321 feet above mean sea level.
Access to the site is along unimproved roads from the exist-
ing Carlsbad Research Center Phase 1 and from Palomar Airport
Road to the southwest.
The site is presently undeveloped. San Diego Gas and Electric
power lines cross the central portion of the site. A City of
Carlsbad Water District water main parallels the northeastern
half of the roadway and crosses the site near the center por-
tion of the alignment (Plates 1 and 2). The southwestern
portion of the area is presently being used by off-road recre-
ational vehicles.
At the time of our investigation a heavy growth of tall grasses
and weeds covered most of the site.
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November 11, 1983 Log No. SD3-2779
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III. PROPOSEV GRAVING
Conventional cut and fill grading techniques will be used to
provide the proposed one percent to 4.7 percent gradient for
the 40 foot wide roadway. Cut slopes up to 50 feet high and
fill slopes up to 45 feet high are planned with inclinations
of 2:1 (horizontal:vertical). It is our understanding that
all proposed slopes are to be considered temporary.
II/, FIELV INVESTJGATJOh!
The field investigation performed during the course of this
investigation consisted of geologic reconnaissance mapping
and subsurface investigation consisting of six drilled bucket
auger borings and seventeen backhoe test pits. The field in-
vestigation was conducted under the direct supervision of our
Engineering Geologist.
A truck-mounted bucket auger drill rig was used to drill six
2 4-inch diameter borings to a maximum depth of 6 4 feet. The
borings were sampled, downhole logged and back-filled, with
samples returned to the laboratory for testing. Logs of the
borings are presented in- Appendix B.
A rubber tire backhoe was used to excavate seventeen test
pits to a maximum depth of 13 feet. The test pits were logged
and backfilled. Logs of the trenches are presented in Appen-
dix B.
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November 11, 1983 Log No. SD3-2779
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1/. LABORATORY TESTJMG
Samples representative of the earth materials encountered
during our field investigation were returned to the labora-
tory for testing. The testing program consisted of moisture-
density determinations, direct shear testing of ring and re-
molded samples, and maximum density-optimum moisture determ-
inations .
Results and descriptions of the laboratory, tests performed
are included in Appendix C.
l/I. GEOLOGY
A. Regional Geology
The subject site is located in the Peninsular Ranges
Geomorphic Province of California near the western margin
of the southern California batholith. The batholith,
consisting of Mesozoic granitic and metamorphic rocks, is
exposed in the higher elevations. Near the Pacific coast,
the batholith is overlain by Mesozoic and Cenozoic sedi-
mentary rocks. Pleistocene sea level floctuations have
left a series of resistant marine terrace deposits on the
older sediments which, when eroded in'the Late Pleistocene
and recently, have formed the dissected mesa and incised
canyon landforms seen today.
Specifically, the site investigated is underlain by Jur-
rassic metavolcanics and Eocene sedimentary rocks. A
marine terrace deposit was encountered at the higher
elevations, alluvial sediments are present in the
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November 11, 19 83 Log No. SD3-2779
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canyon bottoms with colluvial materials present on
the slopes.
A brief description of the geologic units observed within the
site follows below. The distribution of the geologic units
is shown on the enclosed Geotechnical Map, Plates 1 and 2.
B. Geologic Units
1. Santiago Peak Volcanics (map symbol Jsp)
The Jurassic Age Santiago Peak Volcanics underlie the
extreme northern portion of the site. The Santiago
Peak Volcanics are mildly metamorphosed volcanic rocks
ranging from basalt to rhyolite. On-site, the volcanics
are predominately andesitic (see B-1, Appendix B).
As exposed nearby, the Santiago Peak Volcanics are
moderately to highly jointed with spacings ranging from
inches to feet. Most joints and fractures are clay
lined. It is not anticipated that grading for the pro-
posed road will encounter these materials within the
area investigated.
2. Santiago Formation
The Santiago Formation is the most widespread geologic
unit on the site and has been divided into two units
based on the different lithologies encountered in ex-
ploratory excavations and in natural exposures.
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a. Santiago Formation Clay (map symbol Ts ,)
The Santiago^Formation claystone was encountered
in exploratory borings approximately between
elevations 230 and 140 and consists of pale green
thinly bedded claystone, red-brown, sandy to clayey
siltstone and a distinctive dark blue-gray unoxi-
dized sandy siltstone to sandy claystone. The
Santiago claystone is locally sheared along bedding
planes resulting in relatively continuous remolded
clay seams or gouge zones (Borings B-1, B-2, B-4
and B-6; Appendix B).
b. Santiago Formation Sandstone (map symbol Ts^)
The Santiago Formation sandstone was found gen-
erally between elevations 230 and 315 feet and
again at elevations 142 to 96 feet above mean sea
level and is composed of massive to cross-
stratified, light gray silty fine to coarse sand-
stone. Locally, the sandstone is interbedded
with relatively thin siltstone and claystone layers.
Terrace Deposit (map symbol Qt)
Roughly 5 feet of red-brown silty fine sand and
cobbles were encountered at the top of exploratory
boring B-2. This deposit probably represents an ero-
sional remnant of a marine terrace equivalent to the
Lindavista Formation of southern San Diego County.
Alluvium/Colluvium (map symbol Qal)
Alluvium is present in a drainage at the northeast
corner and in the low lying areas at the southwest
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Page Eight
end of the site. The alluvium consists of brown to
light gray loose to soft sandy clay and clayey sand.
Dark gray colluvium, formed by down slope creep and
sheet wash of topsoil, mantles the slopes on the site.
The thickness of the alluvium and colluvium varies
across the site from 2 to 14 feet with the thicker de-
posits in the vicinity of exploratory trenches T-l
through T-6 (Geotechnical Map, Plate 2).
5. Possible Landsliding (map symbol Qls)
Two areas of possible shallow landsliding or bedrock
creep were noted in the areas of B-1 and B-4 (Geo-
technical Map, Plate 1). Aerial photo analysis of
these areas did not reveal clear topographic evidence
of landsliding; however, anomalous bedding attitudes
and remolded clay seams were noted in the upper 16 feet
of B-1 and B-4 that could have resulted from down slope
movement of bedrock materials. The stability of these
areas should be, further evaluated during grading.
Surficial landslides were noted in tributary canyons
northwest of the proposed alignment and will not affect
the proposed grading.
Structural Geology
The Santiago Formation appears to tilt gently to the west.
Local variations in this trend may be attributable to
cross-bedding, lense shaped beds, and channels formed dur-
ing deposition of the formation.
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An apparent separation of 4 8 feet between distinctive
beds in B-4 and B-6 may be the result of faulting between
the two borings. Mapping by others (Appendix A) has
shown numerous small and postulated faults crossing the
site. Based on our investigation, the only evidence of
faulting was in the area between B-4 and B-6. We have
depicted a single fault trace between the borings based on
aerial photographic analysis, although it is possible, how-
ever, that the displacement could be a cumulative effect of
several fault traces in the area. Field mapping and aerial
photo analysis did not show topographic evidence commonly
associated with active faulting nor was there geologic
evidence indicating that the faulting was younger than the
Pleistocene terrace deposits encountered at the higher
elevations of the site. Further evaluation of faulting
will be conducted during grading of the road when greater
exposures are available.
D. Groundwater
Groundwater was encountered in exploratory Boring B-6 as
seepage from joints and fractures. Groundwater was not
encountered in any other excavations or from natural seeps
or springs. Groundwater is not anticipated to adversely
affect grading. If during construction, however, cut
slopes expose seepage, drains may be recommended to en-
hance surficial stability.
E. Seismicity
The site can be considered within a seismically active
area, as can all of southern California. The primary
effect of earthquakes on the proposed roadway will be
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November 11, 1983 Log No: SD3-2779
Page Ten
groundshaking resulting from seismic activity on re-
gional active faults. Table I lists the faults capable
of creating groundshaking at the site. Because of the
nature of grading (temporary cut slopes in firm bedrock
and removal of soft soil beneath proposed fills, ground-
shaking will have a negligible affect on the proposed
alignment.
A. Slope Stability
A review of the proposed grading plans with respect to
the geologic materials encountered during the investi-
gation indicates that the proposed temporary cut slopes
will expose Santiago Formation sand and clay. Because
of the. difference in relative strength, the stability
of the slopes will depend greatly on the type of material
exposed. Because the proposed slopes are considered
temporary slopes, remedial stability measures may not be
necessary if regular maintenance, including clearing the
roadway- of possible slope failure debris, is acceptable.
Final determination of the requirement of remedial measures
will be made in the field during grading by the Geotechnical
Consultant.
Subsequent development in the area should take into con-
sideration that the slopes are temporary and that their
long-term stability should be further evaluated with
respect to future grading.
1. Santiago Formation Sandstone
The majority of the planned slopes will be within
the sandstone unit. Because the sand exhibits a
relatively high shear strength and a generally un-
bedded nature, the potential for deep-seated failures
TABLE I
SEISMICITY FOR MAJOR FAULTS
FAULT
Elsinore
Newport-Inglewood
San Jacinto
San Andreas
DISTANCE
FROM SITE
22 Miles NE
40 Miles NW
4 5 Miles NE
66 Miles NE
MAXIMUM PROBABLE,
EARTHQUAKE
7.0
6.5
7.5
8.0
ESTIMATED
PEAK BEDROCK,
ACCELERATION'
0.18
0.06
0.11
0.09
1. Seismic Safety Study, City of San Diego (1974 and Bonilla 1970)
2. Schnabel and Seed (1973)
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November 11, 1983 Log No. SD3-2779
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is considered low. The low cohesive nature of these
materials, however, may result in erosion due to
surface water runoff. The proposed surface drains
and terrace will minimize the erosion. If the
temporary slopes are not planted, periodic main-
tenance of the road may be needed to remove washed
sand and silt.
2. Santiago Formation Claystone
Slopes at the southwestern and northeastern ends of the
alignment will probably expose Santiago Formation clay-
stone. Where remolded bedding dips out of slope, the
deep-seated stability of the slopes may be reduced.
These slopes should be evaluated during grading to
assess the potential for instability and the need for
remedial grading in the form of stabilization fills
or reduced slope angles.
3. Possible Landslides
Two areas, as depicted on the Geotechnical Map,
Plate 1, may be underlain by landslides. The stabi-
lity of cuts in these materials, will best be
evaluated during grading when larger exposures will
facilitate analysis. At that time, recommendations
for long-term stability measures or short-term
maintenance can be made.
B. Compressible Soil
The subject site is mantled with a variable thickness of
topsoil and colluvium on slopes and ridges that are con-
sidered an unsuitable bearing material for placement of
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Page Twelve
fill. Removal of these soils to firm material will be
necessary to avoid settlement due to the surcharge
affect of the fill. Generally, removals will be on
the order of five feet, although localized areas of
deeper removals should be anticipated.
Alluvium/colluvium present in the southern portion of
the site may necessitate removals of up to 15 feet.
Expansive Soil
It has been our experience that topsoil, colluvium and
Santiago Formation claystone are moderately to highly
expansive. It should be anticipated that relatively
thick pavement sections will be recommended if these
materials are exposed on the subgrade of the road bed.
Suitability as Fill
All on-site soils are considered suitable for reuse as
fill. Santiago Formation sandstone may be suitable for
use as select fill. Topsoil, colluvium and Santiago
Formation claystone may be moderately to difficult to
compact.
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November 11, 1983 Log No: SD3-2779
Page Thirteen
l/III. CONCLUSIONS ANV RECOMUENVATIONS
A. General
Based on the results of our Preliminary Geotechnical
Investigation, we conclude that the project is feasible
from a geotechnical standpoint. There are, however,
two salient geotechnical conditions which may require
special treatment: stability of proposed cut and fill
slopes and the presence of deep alluvial deposits at
the southwest end of the alignment. Although these
conditions will necessitate special remedial measures,
they can be successfully treated during the mass grading
of the site. We conclude that the proposed development
is feasible, from a geotechnical standpoint, provided the
following conclusions and recommendations are incor-
porated into the project plans and specifications.
B. Slope Stability
1. Fill Slopes
Temporary fill slopes are proposed on-site to a
maximum height of about 40 feet. A 40-foot high
fill slope constructed at a slope ratio of 2:1
(horizontal:vertical) should possess gross stability
in excess of the generally accepted minimum
engineering criteria.
Fill slopes more than 30 feet in height shall have
drainage terraces provided at vertical intervals not
exceeding twenty-five (25) feet.
Because temporary fill slopes may be subjected to
several winters before grading is completed, they
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November 11, 1983 Log No: SD3-2779
Page Fourteen
should be built to the same standards as permanent
slopes except that the paved terrace drains may be
deleted.
Fill slopes should be constructed in accordance
with the recommendations herein and the Standard
Guidelines for Grading Projects which are attached
as Appendix D. It is recommended that fill slopes
at 2:1 (horizontal:vertical) less than ten (10)
feet in height be constructed by overfilling and
cutting back to the compacted core.
2. Cut Slopes
a. Santiago Peak Volcanics
No cut slopes are proposed in the Santiago
Peak Volcanics.
b. Santiago Formation Claystone
Subsurface exploration indicates that the pro-
posed 30-foot high cut slopes near the southwest
end of the alignment may expose materials which
are considered unsuitable from a long-term slope
stability standpoint. It is anticipated that a
stabilization fill with a key width equal to one-
half the slope height will be recommended at this
location. The stabilization fill should be con-
structed with backdrains in accordance with the
typical details in the attached Appendix D,
Standard Guidelines for Geotechnical Projects.
Final determination of the requirement for stabi-
lization will be made by the Geotechnical Consultant
during grading. Continuous geologic observation
of the cuts in progress is essential.
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November 11, 1983 Log No: SD3-2779
Page Fifteen
c. Santiago Formation Sandstone
Santiago Formation sandstone will be exposed
in a major 60-foot high cut slope in the central
portion of the site. It is not anticipated that
stabilization will be required in these areas.
Final determination of the need for stabilization
will be made in the field by the Geotechnical
Consultant at the time of grading.
d. Quaternary Terrace Deposits
The Quaternary Terrace Deposits will be exposed
in the upper portion of slopes proposed along
the central portion of the site. It is not
anticipated that stabilization measures will be
required in these areas. Final determination
of the need for stabilization will be made in
the field by the Geotechnical Consultant during
grading.
3. Construction Slopes
Construction slopes in the Santiago Formation are
recommended at slope ratios of 1.5:1 to heights up
to 30 feet. Above that height, construction slopes
are recommended at slope ratios of 2:1 (horizontal:
vertical).
These recommended ratios can be steepened if the
possibility of construction sliding is acceptable.
C. Treatment of Alluvium
Alluvium is present in the canyon bottom areas on-site
and will require remedial treatment prior to fill
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November 11, 1983 Log No:, SD3-2779
Page Sixteen
placement. It is recommended that loose, porous or
saturated alluvium be removed to firm ground prior to
fill placement. For budgeting purposes, it should be
considered that all alluvium will be removed to bedrock.
Alluvium was observed to depths of about 15 feet near
Palomar Airport Road. If a delay between the completion
of grading and future construction is acceptable, sur-
charging is an acceptable alternative to alluvial removal
in this area. Our analysis indicates that a surcharge
of about 15 feet would result in about six months of
delay after grading before subsequent construction could
proceed.
The surcharge operation will require fill placement to
an elevation of 15 feet above proposed finished grade.
The surcharge fill should be compacted to two (2) feet
above proposed finish grade and then placed as stock-
pile. Settlement markers should be installed for moni-
toring after grading.
Our preliminary calculations indicate that enough con-
solidation should occur within six months of the end
of grading to allow construction to proceed in the
surcharge area. Final determination of the settlement
period will, of course, be determined by analysis of
the settlement.
D. Grading and Earthwork
1. Inspection
Continuous inspection by a geotechnical team (Soils
Engineer and Engineering Geologist) during grading
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November 11, 1983 Log No: SD3-2779
Page Seventeen
is essential to confirm conditions anticipated by
the preliminary investigation and to provide data
to adjust designs to actual conditions encountered
during grading.
2. Clearing and Grubbing
Prior to grading, the site should be cleared of
surface obstructions and stripped of brush and
vegetation. Vegetation from the clearing opera-
tions should be removed from the site. Obstructions
extending below finish grade should be removed and
replaced with compacted fill.
3. Site Preparation
a. Treatment of Surface Soils
Test excavations indicate that three to four
feet of surficial soils are present on-site.
The upper portions of the surface soils are
generally dry and porous.
It is recommended that in fill areas flatter
than 5:1 (horizontal:vertical) the upper two
feet of surface soils be overexcavated in areas
to receive fill. In areas steeper than 5:1
(horizontal:vertical), all topsoil will be re-
moved during the benching operation. Final
determination of removal depths will be made by
the Geotechnical Consultant during grading.
b. Existing Fill Soils
It is recommended that all areas of existing un-
controlled fill be overexcavated in areas to
receive fill.
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Treatment of Alluvium
It is recommended that alluvium be removed
or surcharged in accordance with the afore-
mentioned recommendations.
d. Scarification and Processing of Surface
Soils
Following overexcavation of unsuitable'
materials, areas to receive fill and/or
other improvements should be scarified to
a depth of 6 to 8-inches, brought to near
optimum moisture conditions and compacted
to at least ninety percent relative com-
paction .
Compaction and Method of Filling
Fill placed at the site should be compacted to
a minimum relative compaction of 90 percent,
based on ASTM Laboratory Test Designation D 1557-70,
Fill should be compacted by mechanical means in
uniform lifts of 6 to 8-inches in thickness.
Fills constructed on natural slopes steeper than
5:1 (horizontal:vertical) should be keyed and
benched into bedrock or competent natural ground.
Compaction of slopes should be achieved by
overbuilding the slopes laterally and then
cutting back to the compacted core at design
line and grade. Although overbuilding and
cutting back is the preferred method, fill slopes
may be back rolled at intervals not greater than
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Page Nineteen
four feet as the fill is placed, followed by final
compaction of the entire slopes.' Feathering of
fill over the tops of slopes should not be permitted.
Fills should also be placed and all grading per-
formed in accordance with the City of Carlsbad's
Grading Ordinance and the requirements of the
Uniform Building Code.
5. Import Fill Material
Presently, it is not anticipated that import fill
materials will be required. If necessary, however,
the type of material considered most desirable for
import is a non-expansive well-graded granular
material with minor silt and clay fractions. The
Geotechnical Consultant should be contacted for
evaluation of individual import sources well in
advance of planned import operations.
6. Shrinkage, Bulking and Subsidence
Volumetric shrinkage for the topsoil is estimated
to be from 15 to 20 percent. Shrinkage in the
alluvium is estimated to be from 10 to 15 percent.
Santiago Formation bedrock is expected to bulk from
0 to 5 percent.
Because alluvium and porous topsoil are being re-
moved in most of the canyon areas, subsidence there
due to equipment will be negligible. Subsidence will
occur in the surcharge area, and adjustments will
be made during future grading.
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Page Twenty
Due to the fact that shrinkage and subsidence can
vary with many factors, it is recommended that the
above values only be used for preliminary planning
purposes. To provide for unforeseen variations
in actual quantities, a "balance area" should be
designated by the Project Civil Engineer.
E. Surface and Subsurface Drainage
Surface run-off into downslope natural areas and
graded areas should be minimized. Where possible,
drainage should be directed to suitable disposal
areas.
Subdrains should be placed under all fills placed in
drainage courses and at identified or potential seepage
areas. Their specific locations will be determined in
the field during grading. General subdrain locations
will be indicated on the approved grading plan. The
subdrain installation should be reviewed by the
Engineering Geologist prior to fill placement.
Typical subdrain details are presented in Appendix D.
Standard Guidelines for Grading Projects. Subdrain
pipes may be coated metal, P.V.C., or approved equiva-
lent (crush strength of 1000 pounds/foot or greater).
Drainage devices will be recommended behind buttresses
and/or stabilization fills to minimize the build-up of
hydrostatic and/or seepage forces. The details and
recommended locations of these backdrains are presented
in Appendix D. Standard Guidelines for Grading Projects.
Depending on slope height, more than one tier of drains
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Page Twenty-One
Pavements
Due to generally poor subgrade characteristics of the
predominant soil types, generally heavy pavement sec-
tions can be anticipated. For traffic index values of
7.0, 8.0 and 8.5 which are expected for the street
areas, the following preliminary pavement sections
can be utilized for planning purposes.
Traffic Index 7.0 8.0 8.5
R-Value 7.0 7.0 7.0
Pavement Thickness 4" 4" 5"
Aggregate Base 15" 18" 19"
Total Thickness 19" 22" 24"
From review of the above sections, it is apparent that
street areas during rough grading should be kept about
two feet low to accommodate the pavement sections.
Pavement recommendations should be reviewed as final
grades are achieved.
Utility Trench Backfill
Utility trench backfill should, unless otherwise re-
commended, be compacted by mechanical means. Unless
otherwise recommended, the degree of compaction should
be a minimum of 90% of the laboratory maximum density.
As an alternative, granular material (Sand Equivalent
greater than 30) may be thoroughly jetted in-place.
Jetting should only be considered to apply to trenches
no greater than two feet in width and four feet in
depth. Following jetting operations, trench backfill
should be thoroughly mechanically compacted and/or
wheelrolled from the surface.
I
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Page Twenty-Two
H. Grading Plan Review
When final grading plans for the proposed development
are completed, the plans should be reviewed by the
Geotechnical Consultant to determine compliance with
the recommendations presented herein. Substantial
changes from the present plan may necessitate addi-
tional investigation and analyses.
I. Limitations of Investigation
Our investigation was performed using the degree of care
and skill ordinarily exercised, under similar circumstances,
by reputable Soils Engineers and Geologists practicing'in
this or similar localities. No other warranty, express or
implied, is made as to the conclusions and professional
advice included in this report.
The samples taken and used for testing and observations
made are believed representative of the entire area. How-
ever, soil and geologic conditions can vary significantly
between borings, test pits and surface outcrops.
As in most major grading projects, conditions revealed
by excavation may be at variance with preliminary findings.
If this occurs, the changed conditions must be evaluated
The Roll Company
November 11, 19 8 3
Job No: SD1217-00
Log No: SD3-2779
Page Twenty-Three
by the Geotechnical Consultant and designs adjusted
or alternate designs recommended.
Very truly yours,
SAN DIEGa SOILS ENGINEERING, INC,
W. Lee Vanderhurst, C.E.G. 1125
Senior Geologist
Tara S. Sikh, R.C.E. 35454
Senior Engineer
WLV:TSS:SWJ:llr
Reviewed by
Stefohen W
Manager, p
Jensen, C.E.G. 1074
ologic Services
Enclosures Appendix A, References
Appendix B, Subsurface Exploration
Logs of Borings, Figures B-2 through B-27
Appendix C, Laboratory Testing
Appendix D, Standard Guidelines for Grading
Distribution: (6) Addressee
APPENDIX A
REFERENCES
1. "Eocene and Related Geology of a Portion of the San Luis Rey
and Encinitas Quadrangles, San Diego County," December 1972:
University of California, Riverside, Masters Thesis prepared
by R. L. Wilson;
2. Mines and Mineral Resources of San Diego County, 1963:
California Division of Mines and Geology, County Report 3;
3. "Accelerations in Rocks for Earthquakes in the Western United
States," Bulletin of the Seismological Society of America,
Vol. 63, No. 2, Schnabel and Seed, April 1973;
4. Fault Hazard Zones in California, Revised January 1977:
California Division of Mines and Geology, Special Publica-
tion 42;
5. "Fault Map of California," 1975: California Division of Mines
and Geology, Geologic Data Map No. 1;
6. "Repeatable High Ground Accelerations from Earthquakes,"
California Geology, California Division of Mines and Geology,
Ploessel and Slosson, September 1974;
7. Clay Mineralogy and Slope Stability, Special Report 133,
California Division of Mines and Geology, 1977;
8. Seismicity of the Southern California Region 1932-1972, 1973:
California Institute of Technology, Seismological Laboratory;
9. "100-Acre Site, Palomar Airport Road, Carlsbad, California,
Soil and Geologic Feasibility Study," January 1980, Geocon
Inc. ;
10. "Supplemental Preliminary Geotechnical Investigation, Carlsbad
Research Center Phases II and Iii," July 1982, San Diego Soils
Engineering, Inc.;
11. "Aerial Photographs," USDA Flight AXN-8M, 1953, Photo Nos.
71-73, 99-101.
APPENDIX B
SUBSURFACE EXPLORATION
The subsurface exploration consisted of six borings to a maxi-
mum depth of 64 feet and 17 test pits excavated to a maximum depth
of 135 feet. The borings were drilled with a truck-mounted bucket
auger drill rig and the pits were excavated with a rubber tire-
mounted backhoe.
The subsurface exploration was conducted under the direction of
the Engineering Geologist. The borings and pits were logged,
sampled and backfilled. Samples of the materials encountered
were returned to the laboratory for testing.
Logs of our borings are presented as Figures B-2 through B-10.
The logs of test pits are presented as Figures B-11 through B-27.
The locations of the borings and pits included in this appendix
are shown on the attached Geotechnical Map, Plate No. 1 and 2.
California Sampler blow counts were obtained by driving a 2.625-
inch, inside diameter sampler with a hammer dropping through a
12-inch free fall. A 3770-pound hammer was used at depths less
than 30 feet, a 2570-pound hammer was used to depths of 60 feet.
Unless otherwise shown, the blows per foot recorded on the Boring
Logs represent the number of blows used to drive the sampler
12-inches. Samples shown on the Boring Logs as "UNDISTURBED
SAMPLES" were obtained with the California Sampler.
PR IMARY DIVISIONS GROUP
SYMBCX. SECOi-VUARY DIVISIONS COARSE GRAINED SOILS MORE THAN HALF OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE GRAVELS
MORE THAN HALF
OF COARSE
FRACTION IS
LARGER THAN
NO. 4 SIEVE
CLEAN
GRAVELS GW Well graded gr.ivels gcuv/cl-s.ind ninturei. liUie 0' no
fines COARSE GRAINED SOILS MORE THAN HALF OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE GRAVELS
MORE THAN HALF
OF COARSE
FRACTION IS
LARGER THAN
NO. 4 SIEVE
CLESS THAN
5% FINF.S) GP Poorly giaded gravels oi grjvel-sjnd nmiures liiile or
no fines. COARSE GRAINED SOILS MORE THAN HALF OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE GRAVELS
MORE THAN HALF
OF COARSE
FRACTION IS
LARGER THAN
NO. 4 SIEVE
GRAVEL
WITH
FINES
GM Silty gravels, griivel-sand-sill mixiurcs. non-plastic fines COARSE GRAINED SOILS MORE THAN HALF OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE GRAVELS
MORE THAN HALF
OF COARSE
FRACTION IS
LARGER THAN
NO. 4 SIEVE
GRAVEL
WITH
FINES GO Clayey gravels, gravel-sand-clay mniures. plastic fmes COARSE GRAINED SOILS MORE THAN HALF OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE SANOS
MORE THAN HALF
OF COARSE
FRACTION IS
SMALLER THAN
NO. 4 SIEVE
CLEAN
SANDS
(LESS THAN
5% FINES)
SW Well graded sands, gravelly sands, little or no tines. COARSE GRAINED SOILS MORE THAN HALF OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE SANOS
MORE THAN HALF
OF COARSE
FRACTION IS
SMALLER THAN
NO. 4 SIEVE
CLEAN
SANDS
(LESS THAN
5% FINES) SP Poorly graded sands or gravelly sands, little or no fires COARSE GRAINED SOILS MORE THAN HALF OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE SANOS
MORE THAN HALF
OF COARSE
FRACTION IS
SMALLER THAN
NO. 4 SIEVE
SANOS
WITH
FINES
SM Silty sands, sand-silt mixtures, non-plastic fines. COARSE GRAINED SOILS MORE THAN HALF OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE SANOS
MORE THAN HALF
OF COARSE
FRACTION IS
SMALLER THAN
NO. 4 SIEVE
SANOS
WITH
FINES SC Clayey sands, sand-clay miittures. plastic fines. FINE GRAINED SOILS MORE THAN HALF OF MATERIAL IS SMALLER THAN NO, 200 SIEVE SIZE SILTS AND CLAYS
LIQUID LIMIT IS
LESS THAN 50%
ML Inorganic silis and very fme sands, rock Hour si'ty or
clayey fine sands or clayey silts with slight plasticity. FINE GRAINED SOILS MORE THAN HALF OF MATERIAL IS SMALLER THAN NO, 200 SIEVE SIZE SILTS AND CLAYS
LIQUID LIMIT IS
LESS THAN 50%
CL Inorganic cla\-s of low to medium plasticity, gravelly
clays, sandy clays, silly clays, lean clays FINE GRAINED SOILS MORE THAN HALF OF MATERIAL IS SMALLER THAN NO, 200 SIEVE SIZE SILTS AND CLAYS
LIQUID LIMIT IS
LESS THAN 50% OL Organic silts and organic silty clays of low plasticity FINE GRAINED SOILS MORE THAN HALF OF MATERIAL IS SMALLER THAN NO, 200 SIEVE SIZE SILTS AND CLAYS
LIQUID LIMIT IS
GREATER THAN 50%
MH Inorganic sills, micaceous or diatomaceous fine sandy or
silly soils, elastic silts. FINE GRAINED SOILS MORE THAN HALF OF MATERIAL IS SMALLER THAN NO, 200 SIEVE SIZE SILTS AND CLAYS
LIQUID LIMIT IS
GREATER THAN 50%
CH Inorganic clays of high plasticity, fat clays. FINE GRAINED SOILS MORE THAN HALF OF MATERIAL IS SMALLER THAN NO, 200 SIEVE SIZE SILTS AND CLAYS
LIQUID LIMIT IS
GREATER THAN 50% OH Organic Clays of medium to high plasticity, organic silts.
HIGHLY ORGANIC SOILS Pt Peat and other highly organic soils.
200
DEFINITION OF TERMS
U S. STANDARD SERIES SIEVE
40 10
CLEAR SQUARE SIEVE OPENINGS
3/4" 3". 12"
SILTS AND CLAYS
SAND
FINE MEDIUM COARSE
GRAVEL
FINE COARSE
COBBLES BOULDERS
GRAIN SIZES
SANDS.GRAVELS AND
NON-PLASTIC SILTS BLOWS/FOOT *
VERY LOOSE 0-4
LOOSE 4-10
MFOIUM DENSE 10-30
DENSE 30-50
VERY DENSE OVER 50
CLAYS AND
PLASTIC SILTS STRENGTH* BLOWS/FOOT*
VERY SOFT 0 - 1/4 0-2
SOFT 1/4 - 1/2 2-4
FIRM 1/2 - 1 4-8
STIFF 1 - 2 8-16
VERY STIFF 2-4 16-32
HARD OVER 4 OVER 32
RELATIVE DENSITY CONSISTENCY
Number of blows of 140 pound hammer falling 30 inches to drive a 2 inch 0 0 (1-3/8 inch I 0)
split spoon (ASTM D-I586).
^Unconfmed compressive strength m tons/sq. ft as determined by laboratory testing or approximated
by the standard penetration lest CASTM D-1586). pocket penetrometer, torvane. or visual observation
KEY TO EXPLORATORY BORING LOGS
Unified Soil Classification System (ASTM D-2487)
JOB NO.: , _
1217-00
DATE;
NOVEMBER, 1983
FIGURE:
B-1
SAN DIEGO SOILS ENGINEERING, INC.
DATE OBSERVED: ' 10/17/83 METHOD OF DRii I iNd- Bucket Auger
LOGGED BY: LV .GROUND ELEVATION:. 258 LOCATION: Geotechnical Map
P
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uj*£
(OUJ
Oz 20 u
tto
Oo. BORING NO L
DESCRIPTION
SOIL TEST
CL
TOPSOIL; Gray brown silty sandy CLAY;
10-
15-
20-
25-
30-
35-
40-
CL
Push
SM-
CL
CL
SM
CL-j
ML
moist, medium stiff, rootlets, desic-
cated
16.3 L09.C COLLUVIUM: Dark olive brown, slightly Consolidation
sandy silty CLAY; moist, medium stiff,
remolded, massive
SANTIAGO FM; Paid greenish-yellow,
9.1 115,
14.8 112,
mottled orange and olive-brown, sandy .
CLAY and silty SAND mix, moist, very
stiff, dense, less clayey with depth,
0 8' manganese oxide stained bedding
over calcite cemented zone; horizontal
@ 10' gradational to light red-brown,
silty, medium to fine SAND, moist,
very dense
Pale green to olive, silty CLAY; moist,
very stiff, remolded at contact with
sand, N-S, 5°-10° W thinly bedded iron
oxide and sulfide stain on bedding,
E-W 4°-6° N, locally remolded, gypsum
seams
14.9
Gray mottled orange, silty fine SAND;
moist, very dense, thin interbeds of
silty clay; E-W, 8° S
L7.9 L08.?
Olive silty CLAY - clayey SILT; moist,
very stiff, thinly bedded and locally
sheared along bedding; N-S, 5° W, be-
comes massive and very hard @ 21' with
randomly oriented discontinuous gypsum
seams
@ 26' becomes dark reddish-gray
Maximum density,
Shear test
SANTIAGO PEAK VOLCANICS; Dark green
hard aphanitic metavolcanic rock, clay-
filled fractures § 6" spacing
Total Depth 32' REFUSAL
No Seepage
No Caving
Geologically logged to 30'
Backfilled 10/17/83
JOB NO.: 1217-00 LOG OF BORING FIGURE: B-2
SAN DIEGO SOILS ENGINEERING, INC.
DATE OBSERVED: 10/17/83 METHOD OF DRILLING- Bucket Auger
LOGGED BY: LV .GROUND ELEVATION: 321 LOCATION: See Geotechnical Map
P
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OJUJ
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BORING NO i
DESCRIPTION
SOIL TEST
SM TERRACE: Light brown silty fine SAND;
X
damp, dense, abundant cobbles to 6"
diameter, poorly cemented from 2'-4'
5-Contact; Horizontal
SM
9.3L22.e
SANTIAGO FM: Pale yellow-gray, slightly
10-
silty fine SAND; moist, very dense,
local indistinct, lamination; horizon-
tal
@ 8' becomes coarse sand with scat-
tered gravel, moderately cemented
locally
Is
CL
16 X SP
SM
20-
26-
11.5
more gravel with depth
meter
Contact; N-S, 12° E
up to 3" dia-
Dark olive-gray silty CLAY; moist, very
stiff, hard, sheared at random orien-
tation; @ 14' grades to olive-gray,
silty fine SAND, moist-very moist, very
dense
Red-brown, slightly silty, medium to
coarse SAND; moist, dense. Bedding;
N-S, 20° W, highly irregular contact;
40 - 60° S dip
Pale olive-gray silty fine SAND; moist,
dense. Bedding; N 70 W, 4° S
rnnt^pt; N 45 -^Q g
SP 9.2 119. Yellow-gray slightly silty fine SAND;
moist, dense, massive, poorly graded
30-
36-
40-
JOB NO.:
(3 32' bedding; N 60 E, 6° S
0 40' bedding; horizontal
1217-00 LOG OF BORING FIGURE: B-3
SAN DIEGO SOILS ENGINEERING, INC.
DATE OBSERVED:__10Z11Z83_ METHOD OF DRILLING: Bucket Auger
LOGGED RY- ^'^ GROUND ELEVATION: • I nPATioN- See Geotechnical Map
a
Ui
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40-
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^1
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3
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20
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Oa
< t -J w °-z
BORING NO 2_
(CONTINUED)
DESCRIPTION
SOIL TEST
SM SANTIAGO FM; Dark gray-brown fine
SAND; damp, very dense
(3 42' grades to yellow-gray silty
fine SAND;, moist, very dense, massive
45-X
50-
55-
60-
65
Total Depth 64'
No Seepage
No Caving
Geologically Logged to 62'
Backfilled 10/17/83
70
75
80-
JOB NO.: 1217-00 LOG OF BORING FIGURE: B-4
SAN DIEGO SOILS ENGINEERING. INC.
DATE OBSERVED: 10/18/83 METHOD OF DRILLING: Bucket Auger
LOGGED BY:. LV .GROUND ELEVATION:. 288 LOCATION: See Geotechnical Map
P
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a:_i
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0)
3
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coju
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So
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OQ.
it
BORING NO.
DESCRIPTION
SOIL TEST
CL
SC
ML
10-
TOPSOIL; Gray-brown slightly sandy
silty CLAY; moist, stiff, porous,
roots, less granular with depth
gradational contact
SANTIAGO FM; Light gray clayey SAND;
moist, dense, poorly cemented, gra-
velly from 5-6'
Contact; Horizontal
Olive-gray fine sandy SILT,
very stiff, locally clayey
moist,
SM
15-
20-
25-
30-
35-
SM
40-
@ 11' becomes silty fine SAND; massive
@ 19' becomes silty coarse SAND; dis-
continuous, gravel stringers, poorly
cemented locally
@ 27' faint discontinuous lamanae
bedding; N 30 W, 15°-20° S; horizontal
@ 34' 1' thick horizontal well-graded
sand
Irregular high relief contact
Olive-gray silty very fine SAND;
moist, very dense, massive
I
JOB NO.: 1217-00 LOG OF BORING [FIGURE: B-5
SAN DIEGO SOILS ENGINEERING, INC.
DATE OBSERVED:_10/18/81. METHOD OF DRILLING: Bucket Auger
LOGGED BY:. LV .GROUND ELEVATION:. 288 I nnATiriN- See Geotechnical Map
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51
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< t
BORING NO.
(CONTINUED)
DESCRIPTION
SOIL TEST
SP
45-
50-
55-
60-
SANTIAGO FM: Light gray slightly silty
SAND; moist, very dense, medium to
fine grained. Cross-stratified;
E - W/20 - 35 N
(a 48'
25 W
cross-stratification, N 45 E/
15 X 6.3 L18.;
@ 59' lamination; horizontal
65-
70-
75-
80
Total Depth 62'
No Seepage
No Caving
Geologically Logged to 59'
Backfilled 10/18/83_
JOB NO.: 1217-00 LOG OF BORING FIGURE: g-g
SAN DIEGO SOILS ENGINEERING. INC.
DATE OBSERVED: 10/18/83 METHOD OF DRILLING: Bucket Auger
LOGGED BY: LV QRQUND ELEVATION: 235 LOCATION: ^ee Geotechnical Map
-0'
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•e
a
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CO Ul cr_i
30.
QOT
Z
3
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OJUJ
So o
>-a.
Oa
SS
BORING NO 1
DESCRIPTION
SOIL TEST
CL
SM
6-
10-
ML-
CL
15-
ML
20-
CL
25-
30-
ML
CL
35-
40-
TQPSOIL; Dark brown slightly sandy
silty CLAY; moist-very moist; roots
X 10.6L09.C
SANTIAGO FM: Light yellow-olive gray
silty fine SAND; very moist, medium
dense; friable, massive
12
Contact; N lO W, 37°-50° W
11.2L04.7 Dark red-stained silty sand over dark
gray slightly sandy SILT - CLAY; moist,
very stiff; highly fractured, iron
stained on fractures
Bedding; N 10 E 55° W; @ 15' sheared
zone; subparallel, remolded clay seams
@ 1" spacing, clay seams discontinuous
over 1'. Shear; horizontal
Pale olive mottled orange fine sandy
SILT; moist, very stiff; locally
clayey, highly fractured, iron and
manganese stain on fractures, minor
caliche
Dark blue-gray silty CLAY; moist, hard
discontinuous lenses and stringers of
iron oxide stained silt; abundant
randomly oriented, discontinuous gypsum
seams. Bedding; horizontal
(a 27' bedding; N 80 E, 15° S
(a 29' bedding; N 10 W, 5°-10° E
Gradational contact
17.0 Lll.S Dark blue-gray fine sandy CLAY - SILT;
moist, hard; unoxidized, massive,
slab fracture during drilling
Total Depth 40'
No Seepage
No Caving
Geologically Logged to 38'
Backfilled 10/18/83
JOB NO.: 1217-00 LOG OF BORING FIGURE: B-7
SAN DIEGO SOILS ENGINEERING, INC.
DATE OBSERVED: 10/18/83 METHOD OF DRILLING: Bucket Auger
LOGGED BY: LV .GROUND ELEVATION:_174_ LOCATION: See Geotechnical Map
-0
z o
o
CO CO
o UI
00 UJ cr_j 3a
«l
QOT
Z
3
UI*
is
So o
>u:
Oa
i^
SS
BORING NO L
DESCRIPTION
TOPSOIL: Dark gray-brown silty CLAY;
very moist, stiff; roots, desiccated
SOIL TEST
'CL
SM
ML X
10-
15
20-
25-
30-
35-
40-
SANTIAGO FM; Pale olive-gray mottled
orange silty very fine SAND; moist,
very dense
Gradational
16.8L09.S Olive brown fine sandy SILT;
hard, mottled with dark gray
silt; massive, slab fracture
drilling
moist,
clayey
during
@ 20' becomes silty CLAY
@ 25' becomes fine sandy SILT
Total Depth 24'
No Seepage
No Caving
Geologically Logged to 27'
Backfilled 10/18/83
JOB NO.: 1217-00 LOG OF BORING FIGURE: B-8
SAN DIEGO SOILS ENGINEERING, INC.
DATE OBSERVED- 10/19/83 METHOD OF DRILLING: Bucket Auger
LOGGED BY:. LV .GROUND Fl FVATION- 209 LOCATION: See Geotechnical Map
P
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u.
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OTW
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Oa
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SS
BORING NO L
DESCRIPTION
SOIL TEST
SM TOPSOIL: Light brown silty very fine
SAND; damp, loose
SM
5-
10-
15-
20-
25-
30-
35-
40-
SANTIAGO FM; Yellow-brown silty medium
X 6.7 115. E
to fine SAND; damp, very dense;
weathered, friable, local siltstone
fragments, vertical fractures
@ 7' becomes gray-brown
@ 10' becomes moist
Maximum Density
X 10.5 L13.£
@ 14' slight seepage, color change
to light brown, discontinuous around
southern half of hole
X 13.4-L19.C
(3 22' dark brown speckling
(3 23' becomes finer grained
@ 24' 1/4" thick oxidized zone, un-
dulating horizontal
15 X 10.4 L20.S
@ 32' seepage
(§ 33' light brown silty SAND to sandy
SILT; moist, very dense to hard
@ 36' 3"-4" thick well-cemented zone
@ 40' joint with seepage N 75 W, 90'
JOB NO.: 1217-00 LOG OF BORING FIGURE: B-9
SAN DIEGO SOILS ENGINEERING, INC.
DATE OBSERVED:__12Z1§ZM. METHOD OF npii i iMft- Bucket Auger
LOGGED BY: LV .GROUND ELEVATION:. 209 I nr.ATiftM- See Geotechnical Map
a
UJ
o
40-
O
Ul
CQ UJ £r_i
3a
«i
DOT
Z
3
UlS Is
Oz
so o
>-u:
CEO
Da ^Z
< t
SS
BORING NO.
(CONTINUED)
DESCRIPTION
SOIL TEST
SANTIAGO FM: (Continued)
Dark gray slightiy sandy SILT; aamp,
hard
(3 43' joint; N 8 E, 70°-80° NW
(3 45' seepage
@ 46' dark gray gouge zone, 1:5"
thick, very moist, seepage on north
half of hole
(3 46.5' to 47' fine sand lense;
horizontal
ML
45-
50
55-
12
15
14.3 118.E
15.1 114,
12 X 18.1 Lll.
Maximum density
Shear test
60
65-
70
75
80
Total Depth 60'
Seepage 0 14', 32', 40', 45'-47'
No Caving
Geologically Logged to 57'
Backfilled 10/19/83
JOB NO.: 1217-00 LOG OF BORING FIGURE: B-10
SAN DIEGO SOILS ENGINEERING. INC.
I
I DATE OBSERVED: 10/11/8 3 METHOD OF DRit LING: 24" Backhoe
LOGGED BY: KS . GROUND ELEVATION: 90'- LOCATION: See Map
-0-
10-
15-
20-
25-
30-
35-
40-
CL
SC
o
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CQ UJ tr_( 3a
QOT
Z
3
UJ -J a S <
OT
3 GO
X
UJJ5
h
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<!
'OT •z 'UJ
TEST PIT NO. 1
DESCRIPTION
•ALLUVIUM/COLLUVIUM: Light brown
sandy CLAY, moist, soft, minor
organics and roots
BEDROCK; Santiago Formation;
Light yellow slightly clayey
SANDSTONE, moist, medium dense,
massive
Total Depth 8'
No Water
No Caving
SOIL TEST
JOB NO.: 1217-00 LOG OF TEST PIT FIGURE: B-11
SAN DIEGO SOILS ENGINEERING. INC.
DATE OBSERVED:. 10/11/83 METHOD OF DRILLING: Backhoe
LOGGED BY: KS .GROUND ELEVATION:. 96 '-LOCATION- See Map
-0-
o o
u.
«
o -I CO
o
UJ
CO UJ o:_j
3a
^1
QOT
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3
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OTtjU Oz
SO
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>-tL
Oa
<t
SS
TEST PIT NO.
Test Pit located in channel,
approx. 5' below adjacent ground
DESCRIPTION
SOIL TEST
SP ALLUVIUM; Light grey-tan fine-
medium SAND, moist, loose, few
brown CLAY lenses
SC
10-
BEDROCK; Santiago Formation,-
Light yellow-green slightly
clayey SANDSTONE, moist,
medium dense, massive
Total Depth 7-1/2'
No Water
No Caving
15
20-
25-
30-
35-
40-
JOB NO.: 1217-00 LOG OF TEST PIT FIGURE: B-12
SAN DIEGO SOILS ENGINEERING. INC.
DATE OBSERVED: 10/11/83 METHOD OF DRILLING- 24" Backhoe
-1-LOGGED BY:_KS ^^GROUND ELEVATION: 104'- LOCATION: See Map
UJ
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OT <
-I
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t-5 S£<
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3
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SO
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Oa ""Z < t
5S
TEST PIT NO. 3
Test Pit located in channel,
approx. 8' below adjacent grade,
DESCRIPTION
SOIL TEST
SP
SM
10-
15-
20-
25-
30-
35-
40-
ALLUVIUM/COLLUVIUM; Tan,
slightly clayey, medium-fine
SAND, moist, loose
BEDROCK: Santiago Formation;
Light yellow-green silty fine
SANDSTONE, moist, medium dense
Total Depth 7'
No Water
No Caving
JOB NO.: 1217-00 LOG OF TEST PIT FIGURE: B-13
SAN DIEGO SOILS ENGINEERING. INC.
DATE OBSERVED:. 10/11/83 METHOD OF DRILLING: 24" Backhoe
LOGGED BY:. KS .GROUND ELEVATION: 125 ,+ LOCATION: See Map
UJ
-0-
z
O
< o
OT
OT < -I
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O
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u.
OT
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O Ul
CD UJ o:_i 3a •-2
S2<
QOT Z
3
OT|f|
Oz so o
>u:
Oa
< t
TEST PIT NO. 4
DESCRIPTION
SOIL TEST
CL
5-
10-
2M.
15
20-
25-
30-
35-
40-
COLLUVIUM: Brown sandy CLAY,
moist, soft, moderately organic
@ 7' Light brown, clayey SAND
BEDROCK; Santiago Formation;
Light yellow silty very fine
SANDSTONE, moist, medium dense
Total Depth 13-1/2'
No Water
No Caving
JOB NO.: 1217-00 LOG OF TEST PIT FIGURE: B_I4
SAN DIEGO SOILS ENGINEERING. INC.
DATE OBSERVED: 10/11/83 MFTHnn OF ppii 1ING- 24" Rankhop
J-
LOGGED BY: KS -GROUND ELEVATION: 142 ' - 1 or.ATION- See Map 3 DEPTH (FEET) CLASSIFICATION BLOWS/FOOT UNDISTURBED SAMPLE BULK SAMPLE MOISTURE CONTENT (%) IN PLACE DRY DENSITY (PCF) TEST PIT NO. 5
DESCRIPTION
SOIL TEST
CL TOPSOIL: Brown fine sandy CLAY,
moist - wet, soft
5-
SP BEDROCK: Santiago Formation;
Light grey-yellow stained,
fine - medium SANDSTONE, moist,
medium dense, massive
10-
Total Depth 6'
No Water
Minor Caving
15-
-
20-
•
25-
30-
35-
40-
JOB NO.: 1217-00 LOG OF TEST PIT jFIGURE: B_I5
SAN DIEGO SOILS ENGINEERING. INC.
DATE OBSERVED:. 10/11/83 METHOD OF DRILLING: 24" Backhoe
-I-LOGGED BY: KS .. GROUND ELEVATION: 144 ' - LOCATION: See Map
-0-
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CD m cr 3a
QOT
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3
UIJS
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COUJ Oz SO
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CL 0( TEST PIT NO. 6
DESCRIPTION
SOIL TEST
SC ALLUVIUM/COLLUVIUM: Light brown
clayey SAND, moist - wet, loose,
minor organics
5-
10-
SP BEDROCK: Santiago Formation;
Light yellow-brown silty fine
SANDSTONE, moist, medium dense
15-
Total Depth 12'
No Water
Minor Caving
20-
25
30-
35-
40-
JOB NO.: 1217-00 LOG OF TEST PIT FIGURE: g.ie
SAN DIEGO SOILS ENGINEERING, INC.
DATE OBSERVED: 10/11/83 METHOD OF DRILLING: 24" Backhoe
LOGGED BY:_jSS GROUND ELEVATION: 2 00'- LOCATION- See Map
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CQ UJ cr 3a
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3
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OOjlJ
Oz so o
Oa
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ss
TEST PIT NO. 7
DESCRIPTION
SOIL TEST
SC-
CL TOPSOIL; Brown clayey SAND,
sandy CLAY, moist - wet, loose
SP BEDROCK: Santiago Formation;
5-
Light yellow-tan fine SANDSTONE,
moist
10-
Total Depth 4'
No Water
No Caving
15-
20-
25-
30-
35-
40-
JOB NO.: 1217-00 LOG OF TEST PIT FIGURE: B-17
SAN DIEGO SOILS ENGINEERING. INC.
DATE OBSERVED: 10/11/83 METHOD OF DRILLING: 24" Backhoe
,+ LOGGED BY:_KS GROUND ELEVATION: 185'- LOCATION: See Map
Q
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CC 3a
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QOT Z
3
UJ*
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OT|U Oz SO O
Oa
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<t:
SS
TEST PIT NO.
DESCRIPTION
SOIL TEST
CL
ML
5-
10
15-
20-
25-
30-
35-
40-
TOPSOIL; Dark brown silty CLAY,
moist, firm, organics, blocky
BEDROCK: Santiago Formation;
Light yellow-green fine sandy
SILTSTONE, moist, stiff, minor
cemented zones, random frac-
tures, blocky
Total Depth 6'
No Water
No Caving
JOB NO.: 1217-00 LOG OF TEST PIT FIGURE: B-18
SAN DIEGO SOILS ENGINEERING. INC.
DATE OBSERVED: 10/11/83 METHOD OF DRILLING: 24" Backhoe
LOGGED BY: KS GROUND ELEVATION: 225'- LOCATION: See Map
UJ Ul L.
X
I-a UJ
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3a
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QOT
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3
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OT
3 CD
UJ*
OTy
Oz SO
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>-u.
Oa
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< t
ss
TEST PIT NO. 9
DESCRIPTION
SOIL TEST
CL TOPSOIL: Dark brown CLAY, moist-
_ SC-
CL
10
15-
20-
25-
30-
35-
40-
wet, soft, organics
BEDROCK; Santiago Formation;
Light green-grey clayey fine
SANDSTONE/sandy silty CLAYSTONE,
moist, medium dense, fractured
Total Depth
No Water
No Caving
JOB NO.: 1217-00 LOG OF TEST PIT FIGURE: g.ig
SAN DIEGO SOILS ENGINEERING. INC.
DATE OBSERVED: 10/11/83 METHOD OF DRILLING- 24" Backhoe
LOGGED BY: KS GROUND ELEVATION: 204'- LOCATION: See Map
UJ UJ
a. UJ o
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3
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Va
Qa
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< t
ss
TEST PIT NO. 10
DESCRIPTION
SOIL TEST
ML
5-
10-
15-
20-
25-
30-
35-
40-
BEDROCK; Santiago Formation;
olive green fine sandy clayey
SILTSTONE, moist, stiff, frac-
tured
@ 3' less fractured, very stiff
Total Depth
No Water
No Caving
JOB NO.: 1217-00 LOG OF TEST PIT FIGURE: B-20
SAN DIEGO SOILS ENGINEERING. INC.
DATE OBSERVED: 10/11/83 METHOD OF DRILLING: 24" Backhoe
LOGGED BY: KS GROUND ELEVATION: 228'- LOCATION: See Map
-0'
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w
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3a
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Ol
ii
zi
TEST PIT NO. 11
DESCRIPTION
SOIL TEST
SM
SP
TOPSOIL; Brown silty SAND,
moist, loose, organics
BEDROCK: Santiago Formation;
White medium-coarse SANDSTONE,
moist, dense, massive, contact
with topsoil has cobbles and
cemented layer
10-Total Depth 5'
No Water
No Caving
15-
20-
25
30-
35-
40-
JOBNO.: 1217-00 LOG OF TEST PIT FIGURE: B-21
SAN DIEGO SOILS ENGINEERING. INC.
DATE OBSERVED: 10/11/83 METHOD OF DRILLING: 24" Backhoe
+ LOGGED BY: KS GROUND ELEVATION: 164 ' - LOCATION: See Map
O
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3a
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3
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OTUJ Oz so u
Oa "^Z
< t
SS
TEST PIT NO. 12
DESCRIPTION
SOIL TEST
CL
CL
5-
10-
15-
20-
25-
30-
35-
40-
TOPSOIL: Brown CLAY, wet, soft,
organics
BEDROCK: Santiago Formation;
Light green with yellow
staining, fine sandy silty
CLAYSTONE, moist, stiff, frac-
tured •
@ 6' less fractured, very stiff
Total Depth 8'
No Water
No Caving
JOB NO.: 1217-00 LOG OF TEST PIT FIGURE: B-22
SAN DIEGO SOILS ENGINEERING, INC.
DATE OBSERVED: 10/11/83 METHOD OF DRILLING- 24" Backhoe
-1-LOGGED BY:—KS GROUND ELEVATION: 192 ' - LOCATION: See Map
O
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crj 3a
^1
Q« Z 3
Ul*
Is
OTJU Oz SO o
TEST PIT NO. 13
DESCRIPTION
SOIL TEST
CL TOPSOIL: Brown sandy CLAY, wet,
soft, organics
CL BEDROCK; Santiago Formation;
Olive green silty CLAYSTONE,
moist - wet, stiff, weathered
at 3', blocky at 8'
10-
Total Depth
No Water
No Caving
15-
20-
25-
30-
35-
40-
JOB NO.: 1217-00 LOG OF TEST PIT FIGURE: B-23
SAN DIEGO SOILS ENGINEERING. INC.
DATE OBSERVED: 10/11/83 METHOD OF DRILLING: 24" Backhoe
LOGGED BY:. KS ,+ .GROUND ELEVATION: 318'- LOCATION: See Map
-0'
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03 m a:_i 3a
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QOT
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3
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3 01
UJ^S
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OTJU Oz SO
U
>u.
Qa >^
<t
ss
TEST PIT NO. 14
DESCRIPTION
SOIL TEST
SC
SP
5-
10-
15-
20-
25
30-
35-
40-
TOPSOIL: Dark brown clayey SAND
moist, loose, cobbles, organics
TERRACE DEPOSITS;. Light red-
brown SANDSTONE, moist, dense,
cemented, some cobbles, hard
digging
BEDROCK: Santiago Formation;
Light white-green fine-medium
SANDSTONE, moist, medium dense,
massive
Total Depth 4-1/2'
No Water
No Caving
JOB NO.: 1217-00 I LOG OF TEST PIT FIGURE: 5.24
SAN DIEGO SOILS ENGINEERING. INC
DATE OBSERVED: 10/11/83 METHOD OF DRILLING: 24" Backhoe
LOGGED BY: KS GROUND ELEVATION: -254'- LOCATION: See Map
^0-
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OT m <
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UJ
CD UJ
CE_J
3a
QOT
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3
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OTjff
Oz SO
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arc
Ol
<
TEST PIT NO. 15
DESCRIPTION
SOIL TEST
CL
ML
10-
15-
20-
25-
30-
35-
40-
TOPSOIL: Dark brown CLAY, wet.
soft, organics
BEDROCK: Santiago Formation;
Weathered light green clayey
SILTSTONE, with orange staining,
moist, firm
Total Depth
No Water
No Caving
JOB NO.: 1217-00 LOG OF TEST PIT FIGURE: B-25
SAN DIEGO SOILS ENGINEERING. INC.
DATE OBSERVED: 10/11/83 METHOD OF DRILLING: 24" Backhoe
-t-
LOGGED BY: KS GROUND ELEVATION: 235'- LOCATION: See Map
-0-
O
Ul
ffiuj
3a
2<
QOT
Z
3
UJ*
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Oz So
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>-u:
o a
<t:
SS
TEST PIT NO. 16
DESCRIPTION
SOIL TEST
CL
SC
10-
15-
20-
25-
30-
35-
40-
TOPSOIL: Brown CLAY, moist,
firm, organics
BEDROCK: Santiago Formation;
Light green-grey clayey
SANDSTONE, moist, medium dense,
massive
Total Depth 5'
No Water
No Caving
JOB NO.: 1217-00 LOG OF TEST PIT FIGURE: B-26
SAN DIEGO SOILS ENGINEERING. INC.
NORMAL LOAD (PSF)
JOB NO.:
1217-00 LOAD CONSOLIDATION TEST FIGURE:
C-1 SAN DIEGO SOILS ENGINEERING. INC.
DATE OBSERVED: 10/11/83 METHOD OF DRILLING: 24" Backhoe
LOGGED BY: KS .+ GROUND ELEVATION: .250 ' - LOCATION: See Map
-0'
O
UJ
CD UJ cr_i 3a •-2 J2<
QOT
Z
3
UJ
UJ*
Is
Oz so o
TEST PIT NO. 17
DESCRIPTION
SOIL TEST
ML-
CL
TOPSOIL/COLLUVIUM: Light brown
clayey SILT/silty CLAY, moist,
soft to firm
5-
10-
@ 12' weathered bedrock
15-Total Depth 12'
No Water
No Caving
20-
25-
30-
35-
40-
JOB NO.: 1217-00 LOG OF TEST PIT [FIGURE: B-27
SAN DIEGO SOILS ENGINEERING. INC.
APPENDIX C
LABORATORY TESTING
A. Index Tests
Moisture content and dry density determinations were made
for most ring samples. Results of moisture-density deter-
minations are shown on the Logs of Borings, included in
Appendix B of this report.
B. Consolidation Tests
Consolidation tests were performed on remolded colluvial
material. Water was added to the apparatus at the load
indicated on the consolidation curves. The consolidation
test results are presented on Figure C-l.
C. Direct Shear Tests
Direct shear strength tests were performed on remolded
samples. Test results for remolded clay is presented on
Figure C-2. All samples were inundated and allowed to come
to equilibrium prior to shearing with the exception of the
topsoil.
D. Maximum Density/Optimum Moisture Content
The maximum dry density/optimum moisture content relation-
ship was determined for typical samples of the on-site
soils. The laboratory standard used as ASTM: D 1557-78.
The test results are summarized on Table 1, Figure C-3.
4000
3000
u. OT a
X I-
C3 z
UJ oc K
OT
O
Z
CC
<
UJ
X
OT
2000
1000
BORING NO. DEPTH
(FEET)
COHESION.
(PSF) ANGLE OF
FRICTION.° SAMPLE DESCRIPTION BORING NO. DEPTH
(FEET)
COHESION.
(PSF) ANGLE OF
FRICTION.°
Remolded Claystone 4 20 ' 350 11 Remolded Claystone
NORMAL LOAD (PSF)
4000
3000
u.
M a
CJ z
UJ
oc 2000
OT
o z
E <
Ui
X
OT
1000
BORING
NO.
DEPTH
(FEET) COHESION,
(PSF)
ANGLE OF
FRICTION.o SAMPLE DESCRIPTION BORING
NO.
DEPTH
(FEET) COHESION,
(PSF)
ANGLE OF
FRICTION.o
Remolded Claystone 6 47' 450 24 Remolded Claystone
1000 2000 3000 4000
NORMAL LOAD (PSF)
5000 6000
JOB NO.: 1217-00 SHEARING STRENGTH TEST FIGURE: C-2
SAN DIEGO SOILS ENGINEERING. INC.
TABLE I
MAXIMUM DENSITY/OPTIMUM MOISTURE TESTS
(ASTM Test Procedure D 1557-78)
Test
Location
Maximum Dry
Density (pcf)
Optimum Moisture
Content (%)
B-1 (a 20' "105.3 18.6
B-6 @ 8-10' 116.5 8.6
B-6 @ 47' 103.0 19.2
Job No: 1217-00 Date; NOVEMBER, 19 83 Figure: C-3
SAN DIEGO SOILS ENGINEERING. INC.