HomeMy WebLinkAboutCT 81-46; CARLSBAD AIRPORT CENTER UNIT 2; SUPPLEMENTAL GEOTECHNICAL INVESTIGATION; 1988-07-29I
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SUPPLEMENTAL
GEOTECHNICAL INVESTIGATION
CARLSBAD AIRPORT CENTER, UNIT 2,
AND OFF-SITE FILL AREA
CARLSBAD, CALIFORNIA
PREPARED FOR
CENTRE DEVELOPMENT
2111 PALOMAR AIRPORT ROAD
CARLSBAD, CALIFORNIA 92009
PREPARED BY
SAN DIEGO GEOTECHNICAL CONSULTANTS, INC.
6455 NANCY RIDGE DRIVE, SUITE 200
SAN DIEGO, CALIFORNIA 92121
JULY 29, 1988
JOB NO. 05-4879-011-00-00
LOG NO. 8-1797
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TM July 29, 1988
Centre Development
2111 Palomar Airport Road
Carlsbad, California 92009
Attention: Mr. Joe Gie4eman
SAN DIEGO GEOTECHNICAL CONSULTANTS, INC.
SOIL ENGINEERING.& ENGINEERING GEOLOGY
Job No. 05-487~-0)1-rrO-o6
Log No. 8:-1797
, -: '-~;,-
SUBJECT: .
.-~ .
SUPPLEMENTAL GEOTECHNICAL IN'VESTIGATiON--
Carlsbad Airport-Center, Uni t· 2~ -.
and Off-site Fill Area
Carlsbad, California
Gentlemen:
As requested, San Diego Geotechnical Consultants has compfeted·-a
supplemental geotechnical investigation for th.e proposed. -Unit 2'
of the Carlsbad Airport Center in Carlsbad,. CalifornLa.· Our :wo.rE.
also 'covered a limited, area of offsite fill that. ·wil1be~-;-grad~d-:-_-'·--,-~-
as part of the project. This report pr~sen-t's:the' re·~tilts"o~·'6u.r~::·~:.-~----
investigation, as well as our conclusions and'r'ec-ommendat~ons: ... -·:···-
regarding your proposed development of this site.
In general, the development will be feasible from a·geot~c:hnical.-__
standpoint. The major geotechnical constraints will be difficult
excavation of volcanic rock in deeper cuts, the generati:onof
oversize material from ripping or blasting of volcanic rock, the'
removal of compressible alluvium and colluvium in cany.on"bottoms,
and the stability of proposed cut slopes.
We sincerely appreciate this opportunity to serve you.. If you·
have any questions, please call us at your convenience.
Very truly yours,
SAN DIEGO GEOTECHNICAL CONSULTANTS, INC.
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Vice President
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AFB/pb
" . A SUBSIDIARY OF THE IRVINE CONSULTING GROUP, ING.
9240 TRADE PLACE, SUITE 100 • SAN DIEGO, CA 92126 • (619) 536-1102 ., FAX: (619) 536-13.06
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1.0
2.0
3.0
4.0
5.0
6.0
7.0
TABLE OF CONTENTS
INTRODUCTION •••••••••••••••••••••••••••••••••••••••••••••• _. 1
1.1
1.2
Authorization ••••••••••••••••••••••••••••••.••••••••••• 1
Scope of Services ••••••••••••••••••••••••••••••••••••• 1
PROPOSED DEVELOPMENT ••••••••••••••••••••••••••••••••••••••• 2
SITE
SITE
4.1
4.2
4.3
DESCRIPTION.~ ••••••••••••••••••••••••••••••••••••••••• 2
INVESTIGATION ••••••••••••••••••• ' •••••••••.••••••••••••• 3
General •••••••••••••••••••••••••••••••••• ~ ••••••• ~ •••• 3
Field Exploration ••••••••••••••••••••••••••••••• ~ ••••• 4
Laboratory Testing Program •••••••••••••••••••••••••••• 5
GEOTECHNICAL SETTING AND SUBSURFACE CONDITIONS •••••••• ' ••••• 6
5.1 Regional Geology •••••••••••••••••••••••••••••••••••••• 6
5.2
5.3
5.4
Geologic Units ...•.•••.•.•.•••••....•.•.•••••••..•...• 6
5.2.1
5.2.2
5.2.3
5.2.4
Santiago Peak Volcanics (Map Symbol Jsp) ••••••• 6
Santiago Formation (Map Symbol Tsa) •••••••••••• 7
Alluvium (Map Symhol Qal) •••••••••••••••••••••• 7
Fill •••••••••••• ~ ••••••••••• ~ •••••••••••••• ~ ••• 8
5.2.5 Topsoil ••••••••••••••••••• ~ ••••••••••••••••• ~ •• 9
Groundwater ••..•..•.....•.•..•••••.•..•.•••.••..••..•.• 9
Geologic Structure •••••••••••••••••••••••••••••••••••• 9
SEISMICITy •••••••••••••••• " •••• -••••••••••••• ' •••••••••••••• 10
6.1 Earthquake Effects ••••••••••••••••••••••••••••••••••• 10
6. 1 • 1 Surface Fault Rupture •••••••••••••••••• , •• ' ••••• 10
6.1.2 Earthquake Accelerations •••••••••••••••••••••• 11
6.1.3 Seismically Induced Slope Failures •••••••••••• 11
6.1.4 Seismically Induced Settlement •••••••••••••••• 12
6.1.5 Liquefaction •••••••••••••••••••••••••••••••••• 12
6. 1 .6
6.1.7
Lurching and Shallow Ground Rupture ••••••••••• 12
Tsunamis, Seiches, and Reservoir Failures ••••• 12
GEOTECHNICAL EVALUATION AND RECOMMENDATIONS ••••••••••••••• 13
7.1
7.2
General •••••••••••••••••••••••••••••••••••••••••••••• 13
Grading and Earthwork •••••••••••• ~ ••••••••••••••••••• 14
7.2.1
7.2.2
7.2.3
7.2.4
7.2.5
7.2.6
General ••••••••••••••••••••• ~ ••••••••••••••••• 14
Geotechnical Observations •••••••••••••••• ' ••••• 14
Site Preparation •••••••••••••••••••••••••••••• 15
Rippabili ty ................................... 16
Fill Materials •••••••••••••••••••••••••••••••• 17
Fill Compaction ••••••••••••••••••••••••••••••• 19
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8.0
7 • .3
7.2.7
7.2.8
7.2.9
7.2.10
7.2.11
7.2.12
Slope
7.3.1
7.3.2
7.3.3
7.3.4
7.3.5
TABLE OF CONTENTS"
(Continued)
Shrinkage and Bulking •••••.•••••• ~ ••••••••••••• 20
Overexcavation of Bedrock ••••••• , •••••••••••••• 20
Cut-Fill Transitions •••••••••••••••••••••••••• 21
Trench and Wall Backfill ••••••••• _ ••••••••••••• 21
Off-site Fill Area •••••••••••••••••• _ •••••••••• 21
Existing Fills •••••••••••••••••••••••••••••••• 22
Stability •••••••••••••••••••••••••••••••• ~ ••• ~.23
Bedrock and Soil Characteristics •••••••••••••• 23
Cut and Fill Slopes ••••••••••••••••••••••••••• 24
Stabilization and Buttress Fills •••••••••••••• 26
Fill-over-cut Slopes •••••••••••••••••••••••••• 28
Construction Slopes ••••••••••••••••••••••••••• 28
7.3.6 Natural Slopes ••••••••••••••••••• ~ ••••••••••• ~29
7.3.7 Slope Protection and Maintenance •••••••••••••• 30
7.4 Settlement Cons iderations •••••••••••••••••••••••• ' •••• 30
7.,5 Surface and Subgrade Drainage ••••••••.•••••••••••••••• 32
7.6 Foundation Recommendations ••••••••••••••• ~ ••••••••••• 34
7.7 Reactive Soils ••••••••••••••••••••••••••••••• ~ ••••••• 35
7.8 Pavements ••••••••••••••••••••••••••••••••••••• ~ •••••• 35
7.9 Review of Grading Plans •••••••••••••••••••• -•••••••••• 36
LIMITATIONS OF INVESTIGATION •••••••••••••••••••••.••••••••• 36
ATTACHMENTS
Figures
1
2
3
Appendices
A
B
1
C
D
Location Map
Regional Fault Map
Geologic Cross-sections
References
Field Exploration Program,
Boring Logs, Figures B-2 through B-11
Test Pits, Figures B-12 through B-16
Seismic Traverses, B-17 and B-18
Laboratory Testing Program,
Figures C-1 through C-8
Standard Guidelines for Grading Projects
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I' TABLE.OF CONTENTS
(Continued)
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Plates
I 1 and 2 Geotechnical Maps
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SUPPLEMENTAL GEOTECHNICAL INVESTIGATION
CARLSBAD AIRPORT CENTER, UNIT 2,
AND OFF-SITE FILL AREA
CARLSBAD; CALIFORNIA
1.0 INTRODUCTION
This report presents results of a geotechnical inve~tigation
of a proposed commercial project in Carlsbad, California.
The purpose of our investigation was to evaluate the surface
and subsurface soils and geologic conditions at the site
and, based on those conditions, to make recommendations
regarding mass grading and other geotechnical aspects of the
project. Because the project will create rough-graded lots
that will be sold and developed separately, individual
foundation investigations should be made for each lot when
precise grading plans, building locations, and·loading
conditions are known. Our conclusions and recommendations
are based on analysis of the data from our field. exploration
and laboratory tests, and from our experience with similar
soils and geologic conditions in this area.
1.1 Authorization
1.2
This investigation was authorized by Mr. Jim Morrissey
of Centre Development on June 21, 1988. Our scope of
services for this investigation generally conformed to
that outlined in our Proposal No. SDP8-483,J, dated June
3, 1988.
Scope of Services
The scope of services for this investigation included
the following tasks:
a. Review of pertinent geotechnical literature, aerial
photographs, and an 80-scale topographic map by
Rick Engineering, Inc., dated June 7, 1988j
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Centre Development
July 29, 1988
Job No. 05-4879-011-00-00
Log No. 8-1797
2.0
Page 2
b. Geologic reconnaissance of the site;
c. Subsurface exploration consisting of four 8-inch
diameter hollow-stem auger drill holes, three
30-inch diameter bucket auger drill holes, nine
test pits, and two seismic refract·ion traverses;
d. Logging of the drillholes and test pits, with
collection of bulk, disturbed, and relatively
undisturbed samples for laboratory testing;
e. Laboratory testing of samples obtained during the
field exploration;
f. Geologic and engineering analysis of the field and
laboratory data to develop our conclusions and
recommendations; and
g. Preparation of this report with it~ accompanying
maps, figures, and other information to present our
findings, conclusions, and recommendations.
PROPOSED DEVELOPMENT
The proposed development is divided into about 22 separate
commercial lots. We understand that the site will be rough
graded during the initial phases of mass grading, afte·r
which each lot will be developed separately. Our review of
the grading plans indicate that cut slopes to a maximum
height of approximately 35 feet, and fill slopes to a
maximum height of approximately 65 feet are proposed.
3.0 SITE DESCRIPTION
Unit 2 of the Carlsbad Airport Center will occupy a land
parcel of irregular shape located in Carlsbad, California.
The site includes about 70 acres of hills and associated
small drainage basins located east of the existing Carlsbad
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Centre Development
July 29, 1988
Job No. 05-4879-011-00-00
Log No. 8-1797
Page 3
Airport Center, Unit 1. The location and topography are
shown-on the attached Location Map (Figure 1). The site is
bounded on the north and east by McClellan Palomar Airport,
on the south by Palomar Ai rport Road, and on the wes,t by
Units 1 and 3 of the Carlsbad Airport Center.
Topographically, the site includes both low-and .. high-relief
areas. Steeply descending slopes lie near-the western and
eastern boundaries. Natural slopes-within the project: are
approximately 1.5:1 (horizontal:vertical) or steeper on the
canyon sidewalls in the western and eastern portions of the
site. Maximum relief for the site is about 240 feet, with
elevations ranging from about 190 to 330 feet above mean sea
level. The site drains to east-west trending canyons in the
northwestern and southeastern portions of the site and to
several north-south trending. tributary canyons~
Access to the site is along improved roads from the existing
Carlsbad Airport Center, Unit 1. An agricultural reservo_ir
presently exists near the center of the site.
4.0 SITE INVESTIGATION
4.1 General
A previous geotechnical report by H.V. Lawmaster and
Company (Reference 1) includes Unit 2. In addition,
the as-graded report for Unit 1 by Moore & Taber
(Reference 2) describes offsite grading performed in
Unit 2. We reviewed both reports as part of our work.
Before starting field work, we studied aerial photos
and topographic maps of the site to aid in determining
the locations of our subsurface explorations,., This
information, combined with our field investigation,
laboratory test results, seismicity reviews, and
previous experience in the general area, forms -the
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AD APitEQ~~f.RQV·J';.;."Gio'.:..7;5~:ENC'NITAS .('1."'5)
AND' SAN· LUIS REy"n07:5'rQUADRANGLESc
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Centre Development
J.uly 29, 1988
Job No. 05-4879-011-00-00
Log No. 8-1797
Page 4
basis for the conclusions and recommendations in this
report. The study methods used conform to generally
accepted standards of practice for geotechnical
investigations in southern California.
4.2 Field Exploration
Field work began on June 21, 1988, and was completed on
June 30, 1988. During this period, seven bo:rings were
drilled through the,surficial deposits and into the
bedrock. Nine test pits were also excavated during
this period. Two seismic traverses were performed to
evaluate rippability in the area of proposed cuts in
volcanic rock. The approximate locations of the test
pits and boreholes are shown on the Geotechnical Map
(Plate 1). These locations were made in the field by
pacing and by inspection of available maps. Locations
should not be considered more accurate than is implied
by the methods of measurement used.
The boreholes were drilled using an 8-inch diameter,
continuous-flight, hollow-stem auger drill rig and a
30-inch bucket auger drill rig. Samples were obtained
using a standard split spoon sampler and a 2.5-inch
(inside diameter) Modified California sampler. In the
hollow-stem auger drillholes, the drive weight was a
140-pound hammer falling 30 inches. T~e rig kelly bar
was the drive weight in the bucket auger drillholes.
For each drive sample, we recorded the number of blows
needed to drive the sampler 12 inches into the soil.
Three-inch (outside diameter) steel Shelby tubes were
also hydraulically pushed to obtain samples from the
hollow-stem auger drillholes. The test pits were
excavated by a tracked backhoe. Bulk samples only were
collected from the test pits. Each hole or pit was
backfilled upon completion of logging and'sampling.
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Centre Development
July 29, 1988'
Job No. 05-4879-011-00-00
Log No. 8-1797
Page 5
Our field geologist was present to supervise drilling
and test pit excavation. Groundwater condi.tions were
reported as they appeared to the geo:\.ogist at the. time
of drilling. Each borehole and test pit was logged and
sampled for laboratory tests. These logs. are attached
in Appendix B as Figures B-2 to B-16. The boundaries
shown between soil types on the logs· were' interpolated
between sample locations and are approximate only.
Transitions between soil types actually may be either
abrupt or gradual.
Two seismic refraction traverses were made with a Bison
1570C signal-enhancement seismograph, using a 10-pound
hammer as the energy source. Each traverse line 'was
100 feet long, with ham~er stations at 10-foot
spacings. The velocities of compressional waves were
measured and interpreted on the basis of published
charts and local experience to estimate the rippability
characteristics of the bedrock. The results of the
seismic survey are shown on Figures B-17 and B-18 in
Appendix B.
4.3 Laboratory Testing Program
Typical samples of the earth materials found during the
field work were taken to our laboratory for testing.
The testing program included particle-size, Atterberg
limits, in-place density and water content, maximum
density, direct shear, consolidation, expansion index,
sulfate content, pH, and resistivity tests. Appendix C
c'ontains descriptions of the test ·methods and summaries
of the results.
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Centre Development
July 29, 1988
Job No. 05-4879-011-00-00
Log No. 8-1797
Page 6
5.0 GEOTECHNICAL SETTING AND SUBSURFACE CONDITIONS
5.1 Regional Geology
The site is located in the Peninsular Ranges geomorphic
province of California near the western margin of the
Southern California Batholith. Along this margin; the
terrain changes from the typically rugged' landforms
developed over granitic rocks to flatter, more subdued
landforms underlain by sediment'ary bedrock units' of the
coastal plain. Specifically, Jurassic metavolcanics
and Eocene sedimentary rocks lie beneath the si.te.
Alluvial sediments are present in the canyon bottoms.
The dis,tribution of the geologic units is shown on'the
attached Geotechnical Map (Plate 1).
5.2 Geologic Units
5.2.1 Santiago Peak Volcanics (Map Symbol Jsp) "
The Jurassic-age Santiago Peak Volcanics li.e
under the western part of the site. This is a
series of mildly metamorphosed volcanic rocks.
Regionally, the Santiago Peak Volcanics vary in
composition from basalt to rhyolite. On the
site, they are predominant,ly andesite. The
Santiago Peak Volcanics are moderately to highly
jointed. Joint spacings are variable; clay
fillings are usually present. The Santiago Peak
Volcanics are weathered to depths varying from
of about two feet on top of the volcanic peaks
to about 12 feet on lowe~ .slopes. Excavation in
the Santiago Peak Volcanics will be dtfficult.
The highly weathered rock within about five feet
of the existing ground surface can generally be
excavated with conventional heavy earthmoving
equipment. Below that depth heavy ripping and
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Centre Development
July 29, 1988
Job No. 05-4879'-011-00-00
Log No. 8-1197
5.2.2
Page 7
blasting should be expected. Heavy r~ppj.ng or
blasting will generally produce oversi~e
materials. The difficulty 'of handling and
placing these materials in fills will tend to
increase the cost of grading the site.
Santiago Formation (Map' Symbol Ts'a)
The Eocene-age,'Santiago Formation underlies
about two-thirds to three-fourths, of 'the site.
As observed, the unit is massive to thick-bedded
silty to clayey sandstone with interbedded sandy
claystone and siltstone. Santiago Formation
rocks probably can be excavated by conven.tional
earth moving equipment. The claystones'· and some
siltstones are moderately to highly expa!lsive.
5.2.3 Alluvium (Map Symbol Qal) ..
Alluvium is present in the east-west and north-
south trending drainage courses As mapped for
this project, the alluvium includes variable
deposits of colluvium on canyon side slopes·.
Most alluvium and colluvium consists of dry to
moist, porous, soft, silty and sandy clay.
Alluvium was observed to a maximum depth of
about 20 feet at the location of the proposed
off site fill and was, on the averag.e, about six
feet deep. As observed, the alluvium appeared
to be deepest near the center of the drainage
courses, with shallower depths observed along
the margins. The colluvium was observed to a
maximum depth of about five feet and averaged
about three feet deep on canyon sid'e slopes.
The primary concern with regard to alluvium and
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Centre Development
July 29, 1988
Job No. 05-4879-011-00-00
Log No. 8-1797
Page 8
colluvium is their potential for settlement' in
response to loads ,imposed by fills or struc-
tures. Unacceptable settlement may occur aft~r
construction~ especially if these sail~ become
saturated at, a later date. Recommendations to
reduce settlement potential are present-ed, in
later sections.
5.2.4 Fill
A small part of the site is overlain by'-
uncompacted fill and debris. The uncompacted
fill exists in the northern and southeastern
areas of the property. In the northern area,
the material consists of sandy' clay used to
construct an 'agr.icultural reservoi~. At the
southeastern edge of the site, the f.ill is the
result of a prior landfill operation. Th~ fill
consists of rocky soil which may contain some
oversized materials, trash, or debris.-In their
present condition, these materials are not
suitable to support either fill or structural
loads. The expansion potential of the fill
soils is expected to be low to medium. Existing
fill materials may be reused as fill material
for grading if they are properly processed
before use.
Much larger areas along Camino Vida Robles were
filled during the grading of Unit 1 in 1985 and
1986. These are mostly canyon fills with
maximum depths of 20 to more than 50 feet._
According to the as-graded soils report
(Reference 2) these were placed as engi~eered,
compacted fills in accordance with the local
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Centre Development
July 29, 1988
Job No. 05-4879-011-00-00
Log No. ·8-1797
Page 9
standards of practice for such fills. We did
not investigate or test the fill for this
report, and we relied on Reference 2 for all
information relating to the nature and quality
of the site preparation and grading.
'5.2.5 Topsoil
The topsoil seen on the site consisted o.f loose,
dry, fine-grained silty sand. Fills or
structures should not be founded directly on
topsoil due to its limited strength and
potential for settlement and seepage. Topsoil
should have low to moderate expansion potential
and may be used in compacted fills if vege·tation
and organic mate~ia1 is removed. The tops'oi1 . . .
was not mapped and is not shown on Plate 1.
5.3 Groundwater
Groundwater was found in test pits TP-l and TP-2 and in
drillholes BW-l, BW-2 and BW-3 at the contact between
alluvium and bedrock. This is probably a localized.,
"perched" water table and does not reflect the regional
water table. Groundwater conditions may f1uctuat,e with
seasonal rainfall conditions, and will probably change
in response to development of the site.
5.4 Geologic Structure
Most of the dominant structural features in the area
are associated with pre-Tertiary folding along north-
south axes. The post-Cretaceous sequences have been
gently folded and tilted generally to the west. Dips
ranging from 4 to 15 degrees to the southwest were
measured on bedding planes in the Santiago Formation.
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Centre Development
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Job No. 05-4879-011-00-00
Log No. 8-1797
Page 10
Discontinuous northeast-treQding faulting is associated
with the post-Cretaceous folding. Although no faults
were found within the site during our investiga..tion,
faulting has been mapped, in adjacent areas. However,
the closest known active fault is the Elsinore· Faul.t,
about 25 miles to the northeast .•
6.0 SEISK'lCITY
As with all of southern California, this site lies in a
seismically active area. There are, however, no known
active faults either on or adjacent to the site. Figure 2
shows the known active faults and earthquake. epicenters (M >
5.0) in the region and their relationship to the site.
Because the active faults lie at some distance:, the seismic
risk at this site is thought. to be only low to, moderate in
comparison with many other areas of southern California.
Seismic hazards at the site are the result -of ground-shaking
caused by earthquakes on distant, active faults. The hazard
level is sufficient to place the area in seismic risk zone 3
as defined in the Uniform Building Code. Table 1 list.s the
known major active and potentially active faults within a
lOO-kilometer radius and the estimat~d bedrock-accelerations
resulting from the maximum probable earthquakes on those
faults. By definition, the maximum probable earthquake is
the largest event likely to occur in a 100-year interval,
but is in no case smaller than the largest historic
earthquake (Reference 6).
6.1 Earthquake Effects
6.1.1 Surface Fault Rupture
I Because active or potentially active faults do
not cross the site, the probability of surface I fault rupture is very low.
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~~.;\~.,., <t~;("".a;.
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FAULT.
Rose·~..,on4
Elsinore"
. La. Nacipn4
Coronado . Banks
Newport-
Inglewood
San Jacinto
San Clemente
TABLE .. I
SEISMICITY FOR MAJOR FAULTS
DISTANCE
FRCM SITE
10 Miles SW
25 Miles NE
35 Miles SE
40 Miles SSW
40 Miles NW
48 Miles NE
57 Miles SW
MAXIMlM ESTIMATED
PROBABlE... PEAK BEDROCK
FARTHQUAKE~:~ ~CElERATION2
6.0 0.22g.
7.0 0~17g.
6.0 0.05g
6.0 0.04g·
6.5
7.5
7.3
0.06
0.08g
0.07g
REPEATABLE HIGH
. BEDROCK ACCElERATIONS3
. O.14g-
. O'.1:7g,
0;,05g.
. ", O~04g-
0.06
O.08g
0.07g
1. Values are 10cal.magnitudes.-.·l-1aximum;pro1;>able.earthqualce .
. estimates taken from Seismic :8afety study for 'the', City' of' .,"
. San Diego (1974),. employing the method of Bonilla .. (l970) ..
2. From attenuation chart in Seed and Idriss (1982).
3. After Ploessel & Slosson (1974).
4. The earthquake capability of the La. Nacion and Rose Canyon
Faults has not been established. Although the faults are
classed as only potentially active, they are included for
information purposes due to their proximity to the site.
. ' . ,~':" --
-- - -- -
....
•• -.~. ,w._. ____ _
.-~ .
"
~¥ ,~.,-" I : ...
.,-_ .. '---.,
IAII ..... AI ~
, '.,
\'."
1 " • p' • , • r .... ~
.... ..,. ..... , ' C.L ........ ...,. .................... , 'M! Map H 5IL .... "
~ ., ..... ...,.... , ......... eer.H. 'M' , .. 1.-' .
--- --
II.· Ie
--.---DC".,...,
Ie
x
x
x
.,l,
- - - ---- -
__ ._,_ •• --:-_____ • __ -.-", _______ M-
Hlun .. 'C ..
~
'--
\.,---~--~-~--,--...
MAP. Of H'STO~ICEAfrrHQ4A~~--~r'pr:NT~RSJ MJ.\~"lT~'Pt= ) 5.0
'-:~ ,
_ • " ; •• "'):-1 4 ~
: JULY ,'1 ~8e'·1 FIGUR~:-JOB NO.: : .I' . . 05~4879-011-00~OO I;JATE:
2 ,-" ;~r--_;·t-':~· ~~,-~i~-;
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Centre Development
July 29, 1988
Job No. 05-4879-011-00-00
Log No. 8-1797
Page 11
6.1.2 Earthquake Accelerations
1.,"'--
In our opinion, based on~the information now
available, the .most significant ~vent likely t·o
affect this project will be an. earthquake. on the
Elsinore Fault·.·. While a maximum: probCiLbi~ event
on the· ·Ros e ~ Canyon FaU:l t wou~'d'" g'enerate -high
accelerations' ~t the'$ite, the"capabili-ty of the
Rose Canyon Fault to generate such an earthquake
has not been demonstrated. We'ther¢fore
recommend that earthquakes associated with the
Elsinore Fault be used for design and evaluation
purposes at this project.
For Elsinore events,we ~st'imat,eapeak bedrock
acceleration at 'th~s'i te of about O. 17g for a
maximum probable earthquake, of magnitude 7.0.
We do not expect surface accelerations· at this
site to differ s~gnificantly from the bedrock
accelerations. The repeatable high bedrock
acceleration is about 65 percent of the peak
acceleration and is used as a design value for
events occurring within 20 miles of a site.
Beyond 20 miles, the peak acceleration is the
recommended design value (Reference 5). Because
the Elsinore Fault is about 25 miles fro~ the
site, we recommend use of the peak bedrock
acceleration for the structures at this site.
6.1.3 Seismically Induced Slope Failures
Seismically-induced slope failures are not
likely to occur at this site under the design
earthquake loading, provided that proper grading
and construction practices are used.
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Centre Development
July 29, ,1988
Job'No. 05-4879-011-00-0D
Log_ No. 8-1797
6.1.4
Page 12
Seismically Induced Settlement
The bedrock under this sit'e should not undergo
significant settlement as a result of seismic
shaking. However, the' thi-cker alluvial soils
ma~ experience ,small settlements. Anymeasures
taken to, :mitigate".thecotPpressibili,~y'~ofthe-~ .,., " .--. . .
alluviuni~during 'gradings'houid, also ,'dec'reas,e"the
potential for seismically induced set.tlement'.
Recompaction of those soils should reduce' the'
potential for seismically induced'settlement to
insignificant levels.
6.1.5 Liquefaction
Liquefaction is unlikely at this site' due to the
absence of saturation, the fines present ,in the
soils, and the density of the soil.
6.1.6 Lurching and Shallow Ground Rupture
Shallow ground rupture should not be a hazard,
given the apparent absence of active faults in
the area. Ground cracking also should not be a
major hazard.
cracking may
earthquake.
However, it is possible that some
occur at any site during a major
6.1.7 Tsunamis, Seiches, and , Reservoir Failures
The site is not subject to inundation by
tsunamis or seiches because of its elevation
above sea level and its distance inland from a
major body of water. No reservoirs exist that
are capable of flooding the property.
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July 29, 1988
Job No~ 05-4879·011-00-00
Log No. 8-1797
Page 13
7.0 GEOTECHNICAL EVALUATION AND RECOMMENDATIONS
7.1 General
I We did not identify any geotechnical conditions' during
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our-investigation that would preven't;: development;: of the
Carlsbad·. Airport Center, Unit 2, essent;:ially as now
planned. However, the recommendations in this J:"eport·
should be followed to minimize de.lay, inconveniertC'e, or
loss that might arise from the geotechnical conditions
that do exist.
To reduce the potential for damaging se-ttlements, the
existing surficial soil, colluvium, and alluvium shoul.d
be removed prior to fill placement, and the resulting
overexcavation should be made as uniform as practical
beneath the building areas. If areas can be identified
where building.s will not be constructed, such as roads
or parking lots, it may be possible to limit removal of
alluvium to shallower depths,.Th~s determinat.ic;m can
be made upon review of the grading plans.
Many or most of the required excavations can be m~de by
conventional heavy grading equipment; however, blasting
may be necessary in volcanic rocks. Hard rock affects
grading not only as it is excavated (rippability); but
also when it is reused as fi.ll (ove.rs ized rock disposal.
or rockfill).
If practical, soils having sLgnificant potenti~ls for
expansion should be buried at least five f'eet beneath
finish grade. The use of expansive soils at shallower
depths will require that specially designed foundations
or special site preparation be used.
Specific foundation recommendationsshoul.d be made when
details of the buildings to be constructed are known.
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Centre DevelO'pment
July 29, 1988
HO'wever, shallO'w fO'O'ting
if (a) all fO'O'tings in a
O'n bedrO'ck O'r entirely O'n
JO'b NO'. 05-4879-011-00-00
LO'g NO'. 8-1797
Page 14
fO'undatiO'ns shO'uld be suitable
building will bear-eat.it'ely
cO'mpacted fill, (b) the pads
are O'verexcavated sO' that fills will have relatively
unifO'rm thicknesses under individual buildings; and (c)
cO'mpressible SO'ils are remO'ved priO'r to' placing fill.
The remainder O'f this repO'rt explains our geO'technical
recO'mmendatiO'ns in mO're detail. Thes'e recO'mmendatiO'ns
are based O'n empirical and analytical methO'ds typical
O'f the state O'f practice in SO'uthern CalifO'rnia. If
these recO'mmendatiO'ns appear to' nO't cO'ver any s,pecific
feature O'f the prO'Posed develO'pment, please cO'nt,act San
DiegO' GeO'technical CO'nsultants at O'nce for revisiO'ns O'r
additiO'ns to' O'ur recO'm~endatiO'ns.
7.2 Grading and EarthwO'rk
7.2. 1 Gene'ral
The prO'PO'sed development will use cut and fill
grading to' prO'duce building pads~ slO'pes and
street imprO'vements. This grading and earthwO'rk
shO'uld be dO'ne in accO'rdance with the "Standard
Guidelines fO'r Grading P~O'jects" attached to'
this repO'rt as Appendix D, and with Chapter 70
O'f the UnifO'rm Building CO'de. Where special
recO'mmendatiO'ns in the bO'dy O'f this repO'rt
cO'nflict with the guidelines in Appendi~ 0, the
recO'mmendatiO'ns in the repO'rt shO'uld govE!rn.
7.2.2 GeO'technical ObservatiO'n
San DiegO' GeO'technical CO'nsultants persO'nnel
shO'uld cO'ntinuO'usly O'bserve thegradin~ and
earthwO'rk O'peratiO'ns fO'r this prO'ject, S~ch
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Centre Development·
July 29, 1988
Job No. 05-4879-011-00-00
Log No. 8-1797
Page 15
observations are essential to identify field
conditions that differ from those predicted by
preliminary investigat'ions, to adjust d.esigns to
actual field conditions, and to determine that
the grading is in general accordance with the
recommendations of this report. Our personnel
should perfo.rm sufficient testing of fill. during
grading to sUpport the g·eotechnical consultant's·
professional opinion as to compliance of'the
fill with compaction requi.rements.
7.2.3 Site Preparation
The ground should be s·tripped and prepared to
receive fill as recommended in Appendix D. In
addition, the existing colluvium andalluviutn in
building areas should be removed to the depth at
which bedrock is en~ountered. Removals. should
extend beyond the building footprint a mitlimu~
of five feet or to an .imaginary one-to-one plane
extending down and out from the building's outer
edge, whichever is greater. Our personnel itl
the field should observe the depth C!.nd lateral
extent of this removal.
In drainageways where groundwater is present,
full removal of alluvium may not; be practical.
Removals in th.ese areas should extend to depths
at which water inflows or the onset of surfaGe
"pumpin&" make further removals unfeasible. The
resulting subgrade may be loose. and saturated.
Such subgrades may require stabilization prior
to placing fill. A heavy geofabric intended for
stabilization use, such as Mirafi 500X, Prop ex
2002, or Typar 3341, should be installed on the
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Centre Development
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Job No. 05-4879-011-00-00
Log No. 8-1797
Page 16
exposed subgrade. The geo'fabric should then be
covered with a minimum of 12 inch.es of coarse-
grained gravel or crushed rock. If substanti.al
thicknesses of alluvium are left in pl~ce under
fills, settlement monuments should be installed
and monitored during fill placement.
7.2.4 Rippability.
The·proposed grading may involve cuts up to 3'5
feet high in the Santiago Peak Volcanics rock.
Excavability of this rock will probably be Ci
significant factor in site devel0.pment. Data
from the test pits were used with the seismic
refraction data to estimate the rippability o.f
the rock. The velocity, of a compressional wave
can be correlated to ,rock hardness 'and used' as a
indicator of rock behavior during excavation.
The seismic traverses provide useful data down
to depths of about 20 to 30 feet. FiguresB-16
and B-17 in Appendix B summarize the seismic
data and our int'erpretation of it. Reference
reports seismic data from previous studies.
From the data available, the uppermost two to,
five feet in the Santiago Peak Volcanics outcrop
area appears rippable with rela~ive ease by a
Caterpillar D-9 bulldozer fitted with a 'single-
shank ripper. A layer of weathered bedrock,
rippable with moderate difficulty, exists in
places to depths of five to 15 feet below the
present ground surface. This layer is? however,
discontinuous. In many areas, the easi.ly-ripped
surficial layer rests directly on less-weathered
rock that is rippable only with much difficulty,
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Centre Development
July 29, 1988
Job No. 05~-4879-011 ,..00-00
Log No. 8-1797
Page 17
if at all. This layer, which lies at depths of
about four to 15 feet below the present surface,
will probably require a combination of 'bla-st1ng
and hard ripping. Blasting may also be needed
where solid boulders ("floaters") are found iIi
otherwise rippable material.
Once excavated, many of the rock.f.ra-gPlents may
be too larg-e for us·e in normal compacted soil
fills without special plac-ement techniques (see
Appendix D) or placement as rockfill. The size
of rock fragments may be controlled somewhat by
careful design of blasting patterns.
7.2.5 Fill Materials
Any soil imported or excavated from. cuts may be
reused for compacted fill if, in the opinion of
the geotechnical engineer,. it is suitable for
such use. Debris and organic matter sho~ld be
removed from the soil before it is p).aced. The
criteria governing placem'ent of fills depend on
the size of material present. In general, fills
can be divided into "soil", "soil-rock", and
"rock" fills:
a. "Soil" fills are fills cohtaining no rocks
or hard lumps larger thari 12 inches in
maximum dimension and contaitlingat least 60
percent (by weight) of ma-terial passing the
3/4 inch U.S. Standard sieve.
b. "Soil-rock" fills are fills that contain. no
rocks larger than four feet in max~mum
dimension and that have a mat'rix of soil
fill. Rocks larger than 12 inches ~ay be
placed in windrows and by using the other
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Centre Development
July 29, 1988
Job No. 05-4~P9-'011-00-00
Log No. 8-1797
Page 18
techniques described in Appendix D. Some
boulders too large for windrowing will
require special handl.ing during grading.
c. "Rock" fills are fills containing rock
fragments no larger than. 2 feet in maximum
dimension, with no app·reciable fine-g~aine'd
soil matrix. Rock fills require.special
tes ting to monitor compact'ion as recommended
in Section 7.2.6. Cuts in Santiago Peak
Volcanics (Jsp) may quite likel.Y generate
materials suitable for placement in rock
fills.
Fill placed within three feet of, finish grade
should be select fini~h-grade soil. that contains
no rocks or hard lumps greater than six inches
in maximum dimen~ion. For landsca~ing purposes,
the uppermost four inches of f~ill should cont'ain
no rocks or hard lumps greater than two inches
in maximum dimension. Soils with an expansion
index of 21 or higher should not be uS'ed wi thin
three feet of finish grade if practical.
Typical' samples of soil to be used for $oil fill
should be tested by the geotechnical engineer to
evaluate their maximum density, bPtimum mois:ture
content and, where appropriate, shear st.rength
and expansion characteristics. 'During grading
operations, the contractor may encounter soil
types other than those tested for this report.
The geotechnical engineer should be consulted to
evaluate the suitability of these soils for USe
as fill and finish-grade soils. Imported soils
should, if practical, be relatively well-graded,
granular, nonexpansive soils containing small to
moderate amounts of silty and clayey fine~. The
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Centre Development
July 29, 1988
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Log No. 8-1797
Page 19
geotechnical engineer should be contacted at
least two working days before the first use of
an imported soil to c;Lssess its desirability as a
fill soil.
7.2.6 Fill Compaction
Soil and soil-rock fills should be placed as
described in the standard guidelines of Appendix
D, except where those guidelines are superseded
by recommendations in this report. The minimum
compaction for fills is 90 percent of ~odified
Proctor maximum dry density (ASTM D 1557-78).
The water content at placement should be at, or
slightly above the optimum water content.
Rock fill requires special placement me.thods.
The general placement technique is to place a
relatively thin lift of rock, water the lift,
and then compact the lift with heavy compaction
equipment. Heavy vibratory rollers yield the
best results. The actual thj.ckness of each lift
depends on the gradation of the rock. However,
the lifts will probably be about two to three
feet thick. After each lift has been unifo,rmly
spread, it should be sprayed with wat~r to wash
fines through the rock material 'and to lubricate
the rock mass. Water spraying should continue
throughout the compaction process. The wate~ing
ope,ration is essential to adequate compaction of ,
the fill. The volume of water used should be at
least 15 percent of the rock fill volume. At
the start of rock fill construction, a test fill
should be built so that place~ent and comp'action
procedures can be evaluated by the geotechnical
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Centre Development
July 29, 1988
Job No. 05~4879-011-00-00
Log No. 8-1797
Pag.e 20
engineer. Once an acceptable p-rocedure has be'en
established, it may be usedthr01.lghout th~ fill.
The rock fi~l should be brought to finish grade
by placement of a compacted soil fill,cap. This
cap should meet the criteria for finish-grade
fill stated in Section 7.2.5. The gradation of
the rock fill should b~ assessed during grading
by the geotechnical consultant. to determine i~ a
filter is needed between the rock fill and the
soil cap. If needed, this filter may be either
graded aggregate or' a geofabric. The.purpose of
the filter is to ~inimi~e piping of the eaith
fill cap into the voids within t;:he underlying
rock fills. However, local experience, indicates
that a filter may not be ·needed.
7.2.7 Shrinkage and Bulking,
Removal and recompaction of the surficial soLl,
alluvial deposits, and other cut materials will
probably result in shrinkage of about 5 to 10
percent. Bulking in dense alluvium, weath~red
rock, and rippable volcanic rock can be expected
to be about 5 to 10 percent. Blasting or hard
ripping of solid rock will probably result in
bulking of 15 to 20 percent.
7.2.8 Overexcavation of Bedrock
Where bedrock is exposed at finish grade, it is
recommended that an overexca,vation of a,t least,
three feet be made, and that compacted fill be
placed up to finish grade. This will permit the
economical excavation of util.ity and foundation
trenches, and will improve the drainage of the
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Centre Development
Jtlly 29, 198.8
Job No. 05-4879-011-00·00
Log No. 8-1797
Page 21
lots. If deeper utility trenches will be cutF
the overexcavation depth should be increased
accordingly.
7.2.9 Cut-Fill Transitions
Buildings should not be. located over cut/-fili
transitions because of differential settlement
that may occur between bedrock and. compac:ted
fill. In addition, large. changes in fill depth
below structures may cause damaging differential
settlements. The potential for such c'ondi tiotls
should be evaluated during review of the grading
plans. Mitigation of differential sett~ements
usually includes overexcavationof the rock to
produce near-uniform fill. thicknes~es under the
pads, with or without special foundation design.
7.2.10 Trench and Wall Backfill
Unless we recommend otherwtse in specificcas,es,
backfill in trenches and behind retaining walls
should be compacted to at least 90 perc.ent of
modified Proctor maximum density (AS'IM 01557).
The backfill should be placed in uniform lifts
of six to eight inches. Mechanical compactors
normally should be used to achieve the required
density; water-flooding should not: be used •.
When specified, strict at:tention should be given
to special requirements for bedding or hand
compaction around pipes and condui t:s.
7~2.11 Off-site Fill Area
Excess soil and rock generat.ed from cuts 'will be
placed in an off-site fill.. '!he fj.ll area is .in
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Centre Oevelopment
July 2'9 , 1988
Job No. 05-4879-011-00-00
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Pag~ 22
a canyon west of Carlsbad Airport Genter, Unit
1, as shown on Plate 2. In general, off-site
fill should be placed in the same way, and to
the same standards, as mass fill for Unit 2.
The canyon does, -however, contain at least-15
feet of uncompacted agricul.tu;-al-fill and 10
feet of alluvium. Both materials are highly
compressible and should be completely removed
before the off-site fill is placed.
7.2.12 Existing Fills
Two classes of existing fill are pres,ent on the
site. The first of these is agricultural fill,
including that placed for land--levelling and
that placed for" dams and stock ponds. This fill
is entirely undocumented and is p.ro,bably ot poor
quality. All agricultural and undocumented filT
shquld be completely removed during grading.
The second class of fill is orf-site fill placed
during grading of Carlsbad Airport Center, Unit
1. This fill mostly adjoins Camino Vi.da Roble
along the south edge of Uriit 2. For the most
part, it consists of canyon fills vary~ng from
less than 20 to more than 50 feet thick. This
fill was observed and tes'tedby Moore & Taber of .
Anaheim, CaJ.,ifornia, in 1985 and 1986. Their
as-graded report (Reference 2) states that the,
fill was properly placed and compacted on a
correctly prepared surface. Because San Diego
Geotechnical Consultants did not observe any of,
this gradi-q.g, and bec.;luse our scope of services
did not include subsurface exploration of the
canyon fills, our recommendations for further
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Centre D~velopment
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grading rely on Moore & Taberls representations
regarding fill quality. We therefore recommend
that the surface of this fill be strip~ed of any
loose, dry, or otherwise unsuitable soiL. The
stripped fill surface should then be scarified,
moistened, and compacted in the same way as the
native soil surfac'e prior to re~eiving ~ill.
7.3 Slope Stability.
7.3.1 Bedrock and Soil Characteristic's
Slope stability conditions vary greatly over the.
site. Although most of the soiL and rock have
moderately high shear strength, weaker rock is
present also. This weaker rock often includes
low-strength discontinuities. Nevertheless,
both the natural and man ... made slopes should be
stable over the life of the project if proper
care, prudence, and skill are. applied to their
construction and maintenance. The current
absence of free groundwater over most of the
site enhances the· stabil.ity of slopes. Care
should be taken, though, to prevent or minimize
the development of groundwater .seepag.e during
the post-construction period.
Soil strength parameters us.ed in analysis were·
based on laboratory test results, on data from
other local proj ects, and on our ,experienc'e and
judgement. For silty sandstone and similar weak
rocks (mostly Santiago Formation), a c'ohesion of
100 psf and an effective friction angle of 31
degrees was chosen. For clayey sandstone and
claystone, a cohesion of 400 psf and a. f.riction
angle of 26 degrees was used. Fills built from
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Centre Development
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Job No. 05-4879-011-00-00
Log No. 8-1797
Page 24
mixtures of these rocks were assumed to have a
cohesion of 200 psf and a friction angle of 29
degrees. For pre-sheared clay seams in the
bedrock, a residual friction angle of 12 degrees
was assumed, with no cohesion.
(
Cut slopes in the Santiago Pe~k Volcanics were
not analyzed for stability in the usual way.
The stability of hard rock slopes is controlled
by jointing, the nature of fracture fillings,
and the prsence of seepage. Analyses based on
mass strength parameters are usually misleading
because they do not account for the geometry or
mechanisms of rock failure. Accordingly, the
stability of th~ rock slopes was judged on the
basis of experience and local practice.
7.3.2 Cut and Fill Slopes
The proposed fill and cut slop~s will mostly be
built to maximum heights of about 40 feet ~We'
assume that they will be built at slope ra·tios
of 2.0 (horizontal) to 1.0 (vertical), will have
level surfaces behind their crests"will not be
subj ect to significant surcharge loads, and wi,ll
not become saturated. Unde.r these assumptions,
the slopes may be built' to the following maximum
heights:
Slope Type and Material
Cut; Silty Sandstone (Tsa)
Cut; Clayey Rocks (Tsa)
Fill; Mixed Soils
Slope Height, F~et
51
83
TZ
These heights are based on Taylor's charts, with
static factors of 1.5. They therefore should
meet local state-of-practice standards for slope
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Centre Development
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Log No. 8-1797
Page 25
stability. Slopes not confor~ing to the stated
assumptions should be individually studied prior
to construction of the buildings" Cut slope.s ih
Santiago Peak Volcanic rocks should be stable to
heights of at least 35 to 40 fe.et. As discussed.
above, though, the st'abili-ty of these hard rock
. slopes will depend heavily on structural factors
that must be assessed during grading.
Two atypical slopes have been plann~d fo-}; the
site. In the eastern part of the tract;, along
Palomar Airport Road, a fill slope will rise up
to about 65 to 70 feet above the valley floor.
In its highest section, the slope gradient will
be 3:1 (horizontal:vertical), with an eight-foot
bench at a height of 40 feet. This slope should
have a factor of safety of at least 1.5, subject·
to the assumptions stat.ed above·. However, the
factor ~f safety against a toe failure shpuld be
reassessed during grading if high groundwater
levels will prevent full ~emoval of alluvium or
saturate the toe.
The second atypical slo~e is in the eastern part
of the site, where the north property line abu·ts
the developed part of the airport. A planned . .
slope about 30 to 32 feet high will be cut-down
from the property line, just below an existing
fill slope. This cut slope should be stable if
no presheared clay seams are p'resent ahd if the
other assumptions stated above are met. If not,
though, mitigation measures may be needed •
Despite the overall stability of the slopes,
some erosion, ravelling, or thin surficial
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Centre Development
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Job No. 05~4879-011-00-00
Log No. 8-1797
Page 26
sliding may occur on otherwi&~ stable slopes if
they are not well vegetated or maintained after
construction. Groundwater seepage, frac~tures
and other unfavorable geologic struc~tures, or
variations in soil and rock propert:i.es may lower
the stability' of cuts greatly. Such condit~iorts
usually can be assessed only when soil arid rock
is exposed during grading. For this reason, San.~
Diego Geotechnical Con~ultants personnel should
observe all slopes during grading to evaluate
the geologic conditions.
In particular, cut slopes in clayey rocks of the
Santiago Formation ar~ very likely to contain
weak seams of soft, pre-sheared clay. Multiple
seams were found'ill our drillholes 'B-1 and B-3,
in the center of Unit 2 (Figure 3). Similar
conditions were reported throughout Unit 1, and
stabilization or buttress fills were const~ructed
on most of the larger cut slopes in that unit.
The diversity of slope heights and ori.enta;tions,
and the unknown number, lc;>cation,·and attitudes
of the clay s'eams present, require an assumption
that most cut slopes in Santiago Formation ~rock
will require stabilization or butt~ressing.
7.3.3 Stabilization and Buttress Fills
Given ,the information now known, stabilization'
or buttress fills probably will 1;>~ needed on
most of the cut slopes in Sar:ttiago Formation
rocks. Moore & Taber noted that the slopes cut
along Camino Vida Roble during the grading of
Unit 1 would need stabilization (Reference 2).
Observations in drillholes B-1 and B-3 indicate
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,~~"-/-,.' . . -.-, . f~~;;~.. . A:A~, i ' .. :"c;,: N 11° W -.~;;, £\~:~: . . J" ' ... ~' I~' ." A A'
rio 2"';;;, ~;r' ' ," ," ,. " ",:;" " DR,nHRi,v~"\ I EX"i:'rINQ~:~,~ii,N D SUR FAC "1 ,,-TO paolL
~~~o 7~;'ii'
J 7,
-1--~t---·-";"-----' ..... _ . ..,.;.-. ....,;. __ . ___ ? . , I' -.. ' v· "', . ·.A '~r, ( I ·A. . . _ '.
~"t~'
.. ')
B8'''''; "'w . ~
300,
,·:'k·,r -.
J~I~.::_.·
".:'\.1' ,: .. ,-.
~ ·~~.I.::.
"~}If~~ .-
, '.~~:...:. ~~. ,
''':f~;~
,' .....
J'."; .. ,,·t.,~ ;
,"~'/.~' :: .. ~ ,-·>t~·~,;0
:<':~I:' ",~}J:
'~;~-';' , ..,1.i~:-' ::'
.....
1-·,2'8 < .. '
SllTY'S.ANDST'~N:E. 'I -->~ ~._?, ,
. . I '\ '. . :-~I~-. S:A:r.D'Y CLAY$T.~'NE
. .~~I-"" '" _' 'I , • '. ~ , -~... ., A _",_I'.': r . (,:. . ,~fo-~ . A' .. \._
CLAYEY SAND'S:TON~ /'" .. I , . ,"" 1·./' SILTY SANDSTn~~ ·r· PRQPOS1 EO:'~RA'DE~ SURF.ACE._~·· : -",<t .. ' 1 . . 41 . .... . L-"
~--I------~, '"',<,,' SANDY CLAyS~~NE
lsa I ,I III I i I
CR·Q;·S 8'''''-S E:C,T'IO,N,:.AA";"'AA!,
SCALE:-1 INC:H=20 FEET
N4f!E" TE
I ~ , t
! ~
\ (:.
II ~
~B!
,,~
t
r---
W .,. ____ , '
.W 'i
LL. " .
Z ~' j
, : I • I Z ';': I'
0,280 ~ i=. PROPOSED' GRADED < SURFACE
> I --4-----~--~' W _____ ---l--------~+---
-' W
, 2-4 01 _ I I . i '
,
Tsa,
_---+~ .. 7~~---...·-I..
Tsa~
EX:PLANATION
8A·NTIAGO FORMATION
TOPSOIL/BEDROCK CONTACT
·CONTACT BETWEEN BEDROCK TYPES . A-A CLAY SEAM WITHIN BEDROCK '
NOTE-: GEOLOGIC CONDITIONS
ARE SHOWN AS
LOGGED IN. DRILLHOLES. EXTRAPOLATION O~· CONDITIONS AWAY ~ROM DRILLHOLES IS UNCERTAIN AND 8U8JECT TO CONFIRMATION DURING GRADING.
I' I I ! d
CROSS-SECTIO,N BB-BB'II CARLSBAD AIRPORT CENTER; IJIIIIT 2
,SCALE: 1 INCH-20 FEET , .1: c;:ARLSBAD" CAUFO~
G-EOLOGIC CROSS-SECTIONS
" CENTRE. DEVELOPMEN"T
SEE ·SUPPI::E:M,EN'"TAL G.EOT·ECHNIC,AL INY·ESl'IGAT.ION··· MA.P ("PLA,[£~1) FOR'LOCATIONS OF °C'ROSS"'SECTIONS~ i!.j _110.:,.0 •• 11;"
J':'~
:Jii, ~." ~."-
---~-.. -... _.-... ~--,. -_.----..
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Centre Development
July 29, 1988
Job No~ 05-487g~011-00-00
Log No. 8-·1797
Page 27
that. almost any cut slope in the centr~lpart of
the site may need stab:i.lization as well. Clay
seams in Santiago Formation rocks may be less
common in the east part of the site. However,
observations during grad:i.ng may identify such
seams in that area as well.
For planning purposes, it should be assumed that
stabilization fills at least 15 feet wide will
be required at all significant cut slopes in the
Santiago Formation. Typical details of' buttress
and stabilization fills can be found in Appendix
D. The actual size and extent of sta'biLization
fills and buttresses should be designed during
grading, when geologic conditions are adequately
exposed. We recommend that false cuts' he .used
to construct the cut slopes, sO that geologic
conditions can be mapped ,and assessed before the
final cuts are made. If the preseqce or nature
of the clay seams. cannot be properl.y ass.es's·ed
from the false cuts, ,large-diameter boreholes
should be drilled and logged at critical points.
Careful planning and coordination between the
contractor and the geotechnical engineer will be
needed so that this work can be doqe without.
undue expense and delay. In theca.se of slopes
along the north pI'o.perty line, very l.i ttle room
exists in which to build buttresses and slope
failures might damage; airport. facilities. We
recommend that contingency plans for modifying
the grading in this area be made in advance, in
the event that stabili~ation is needed.
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Cent~e Development
July 29, 1988
Job No. 05-4879-011-00-00
Log No. 8 ... 1797
Page 28
7.3.4 Fill-over-cut Slopes
Where fill-over-cut slopes are proposed, the cut
portion should be finished before fill placem~nt
begins. A keyway, at leas,t one equipment-width
wide (about 12 to 15,feet), should be built at
the cut/fill contact. Also, a subsurface drain
should be placed along the rear of-the keyway.
The drain may consist of perforated PVC pipe
surounded by gravel or crushed rock and wrapped
with geofabric. This drain should lap up onto
the rear of the keyway at least six inches above
the cut/fill contact. Alternative drain designs
should be submitted to San Diego Geotechnical
Consultant's for review prior to, use.
7.3.5 Construction Slopes_
In the absence of surcharge loads_, groundwater
seepage, or presheared clay seams, temporary_
excavations and slop.es may be cut to, the slope
ratios and heights I_is ted below:
Slope Ratio Height of Slope z Feet
(Horiz. : Vert.) Fill .Q&, Tea Jsp
Vertical 4 3 4 4
O.75:1~0 26 7 15 -10
1.00:1.0 44 11 26 20
1 .25: 1 .0 20 48
Slopes higher than. those listed above should be
built on the basis of s_pecific recomm'endations
made by the geotechnical engineer.
If surcharge loads (such as equipment, material
stockpiles, or spoil banks) are placed along the
edges of excavations or slopes, the ~:dope ratios
should be flattened from those .givenabove. For
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Log No. 8-1797
Page 29
planning purposes, we recommend flatteping when
surcharge loads fall within a zone defined by a
1:1 plane rising from the nearest. bottom corner
of the excavation or slo.pe. Contact San Piego
Geotechnical Consultants if such surcharges will
exist for specific recommendations~
Water should not be allowed to flow freely over
the tops of temporary slopes. Workmen should be
protected from the local ravelling and surficial
sliding that may still occur at the slope ratios
listed above. Tempo·rary slopes and excavations
subjected to severe vibratory loads should be
analyzed for dynamic stability. All temporary
excavations should meet at l.east the minimum
requirements of applicable occupational safety
and health standards. San Diego Geotechnical
Consultants should be contacted for further
recommendations if soil conditi.ons are found
that deviate from those assumed Or if evidence
of instability appears at the site.
7.3.6 Natural Slopes
With the exis.ting slope ratios and grou,ndwater
conditions, the natural slopes on and near this
site presently appear stable. If drainage is
provided and the grading recommendations in this
report are observed, development of this tract
or adjoining properties should not cause these
slopes to become unstable •. However, we should
review this conclusion when grading plans are
complete and during the grading operation.
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Centre Development
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Job No. 05-4&79-011-00-00
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7.4
Page 30
7.3.7 Slope Protection and Maintenance
Although graded slopes on this site should be
grossly stable if built in accordance with the
recommendations in this repo:t't~ the soils will
be somewhat erodible. For this reason, the
finished slopes should be planted as soon as
practical after the end of construction.
Preferably, deep-rooted plants adapted to semi-
arid c1imate~ should be ~sed. In addition,
runoff water should not be permitted to drain
over the edges of slopes unless the 'water is
confined to properly designed and constructed
drainage facilities.
Settlement·· Cons iderations
Both the weight of the new fill and the loads impos~d
by buildings and structures will producese,ttlement.
Some degree of settlement will occur in compacted fill
and in the underlying native soil and rock. Howeve.r,
settlements within rock of the Santiago Formation and
the Santiago Peak Volcanics should be negligible. If
compressible soils are properly removed and ~ep1ac.ed
with compacted fill, settlements within the native
materials should not be significant.
If groundwater prevents the full removal of alluvium or
other compressible soils from beneath fills, buildings
or other settlement-sensitive structures should not be
built until primary settlement of both the alluvium and
the fill is essentially complete. Settlement monuments
should be installed at the base o.f fills and surveyed
at intervals during and after fill placement if more
than five feet of alluvium will remain in piac'e. San
Diego Geotechnical Consultants cart then review the
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Centre Development
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Job No. 05-4879-011~OO-OO
Log No. 8-1797
Page 31
survey data to evaluate the progress of settlement.
Our experience in the area i$ that $ettlementls,
buildings or other s.ettlement-sensitive structures
should not be built until primary settlement o·f both
the alluvium and the fill is essentially complete.
Settlement monuments should be installed at the bas·e of
fills and surveyed at intervals during and after fill
placement if more than five feet of alluvium will
remain in place. San Diego Geotechnic'al Consultants
can then review the survey data to evaluate the.
progress of settlement. Our experience in the area is
that settlement is largely compl.ete within three to
four months after completion of the fill.
Compacted fills normally settle under their own weight
by approximately 1/4 pe'rcent to 1/2 perc'ent of-their
Qriginal height following construction.. Although inuch
of this settlement occurs during t.he construction
period, the structures. planned for this site should be
designed to withstand settlements of this magnit~de.
Compaction of the fill at water contents above optim~m
should minimize the potential for' .future set.tlements if
the fill later becomes saturated. If the settlement of
the fill under its own weight is not tolerable, the
total amount of settlement affecting structures can be
reduced by delaying construction of buildtngs tinti,.l the
settlement is largely complete. This will require that
settlement monuments, like thos'e described above, be
installed and monitored. Settlement monuments may also
be used if there is any question as to the ability of
the fill placed during grading of Unit 1 to support, new
fill without excessive settlement.
Estimates of settlement due to h.lJ.ilding loads depends.
on the design of the building and on the foundation
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system selected for use. Reli.able estimates therefore
cannot be made until foundation investigations are made
for individual buildings. If designed fo-rappropriate
bearing pressures, though; shallow found,at.ions should
generate total and differential settlements that fall
within limits generally conside·red accept-able.
7.5 Surface and Subgrade Drainage.
Foundation 'and slab performance depends greatly on how
well the runoff waters drain from the site. This is
true both during construction and over the en:tire life
of the structure. The ground surface around structures
should be graded so that water flows rapidly away from
the structures'without ponging. The surface gradient
needed to achieve this depends on landscaping type.
Pavements or lawns within five feet of building$ should
slope away at gradients 0'£ at least 2 percent.' Dens'ely
vegetated areas should have minimum gradients of 5
percent away from buildings in the first five feet if
it is practical to do so. Terrace drains should be
constructed on fill slopes at intervals not exceeding
30 to 40 vertical feet. The benches fo,r terrace drains
should be at least six feet wide. Drainage facili totes
should be regularly maintained,' cleaned, and re,paired
so that they will function p·roperly.
Planters should be built so that water from them will
not seep into the foundation areas or beneath slabs and
pavements. Maintenance personnel should be inst.ructed
to limit irrigation to the minimum actually necess.ary
~o properly sustain the landscaping plants~ Shquld
,excessive irrigation, wa~erline breaks, or unusually
high rainfall occur, saturated zones and "perched"
groundwater may develop in the soils. Consequently,
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Centre Development
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Job No. 05-4879-011-00-00
Log N9. 8-1797
Page 33
the site should be graded s'o that water drains aw~y
readily without saturattng foundation or landscaptng
areas. Potential water s'ources, such. as water mains,
drains, and pools, should be frequently examined for
signs of leakage or damage. Any such leakage or damage
should be repaired pro~ptly.
Subdrains should be installed at the base of fills,
placed in drainageways or over areas of actual or
potential seepage. The general locations of subd.rains
should be indicated on the grading plans. Spe<;:ific
locations should be determined in the field during
grading, with installations being reviewed by San Die'go
Geotechnical Consultants prior to the fill place~ent.
Appendix'D includes typical details of subdrains.
Subdrain pipes may be o£ coated metal, plastic, or
other corrosion-resistant mat.erials. The pipe shQuld
have adequate structural streng~h towithstartd the
loads imposed by fills, structures, and live loads .•
The recommended subdrain type consists of a perforated
pipe surrounded by free-draining gravel or crushed
rock. The rock, in turn, is wrapped with geof.abric.
We recommend the following pipe sizes for the drains:
Total Run Length
o -400 ft.
400 -800 ft.
More than 800 ft.
Pipe Diameter
4 in.
6 in.
8 in.
About nine cubic feet of rock should be useq for each
lineal foot of subdrain. The gravel or crushed rock
should be a nondegrading, durable,' opetl-·graded material
with a maximum grain diameter of 1.0 to 1.5 inches. It
should not have more than three percent (by weight) o·f
fines passing the No. 200 U.S. Standard sieve, as
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Centre Development
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placed. The fines should not;, have a plasticity index
(AS'IM D 4318-84) greater than 4.0. The geo-fabric
should be a high-permeability, nonwoven fabric such as
Mirafi 140N, Prop ex 4545, or Typar 32-01. The outlets
o_f subdrains, should be mapped at, the end of grading and
accurately shown on the as-built, plans. Thereafter,
the outlets should be cleaned and repaired at, frequent
intetvals to prevent burial or blockage.
7.6 Foundation Recommendations
Bearing capacities, foundation dimensions, pressures on
retaining walls, and other foundation recommendations
depend on structural details of the s~ec~fic buildinas
to be constructed and on economic and constructa'bility
concerns. As the indiv.idua1 lots in Un_it, 2 will be
marketed for ul.timate development_ by others, detailed
recommendations are premature at this point •. Separate
foundation investigations should be made for each I,ot
when it is developed. The foundation recommendations
can then be guided by the specific requirements of e'ach
building and structure.
In general, the building pads should be suitable for
the support of moderate foundatiOn loads typical of
one-and two-story concrete tilt-up structures. The
allowable bearing capacities fo,r conventional sp'read
footings and strip footings should be at least 200'0
psf. Foundation costs can be minimized. 1.f (1) the lots-
are capped with at least 3 feet of nonexpansive or 10w-
expansive soil, and (2) buildings are not locatedove~
transitions from bedrock to fill or over areas where
large changes in fill depth occur across the building
footprint. Both of these provisions are incorporated
into the recommendations of this report.
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July 29, 1988
7.7 Reactive Soils
Job No. 05-4879-Glt-OO-Oo
Log No. 8-1797
Page 35
Based on chemical tests and our experience with similar
soils, either Type-I or Type II Po·rtland cem.ent tnay be
used for concrete in contact with th~ soil •. However,
the absence of water-soluble sulfates .in the soil and
rock should be confirmed at the comp.lE!t:ion of:grad:Lng.
7.8 Pavements
R-value tests were not made because the ~oil types in
the subgrades of streets and parking areas will not. b~
known until grading is complete. It is cons·ervative to
assume, however, that relatively poor subgradesand
thick pavement sections will be needed. For traffic
indices of 7.0,8.0, and 8.5 which are typical fo:r the
street areas, the following pavement ~ecttons; can be
used for planning purposes:
Traffic Index 7.0 8.0 8.5
R-value 10.0 10.0 1'0.0
Pavement Thickness 4" 4" 5"
Aggregate Base 14.5" 18" 1 8"
Total Thickness 18.5" 22" 23"
These sections indica.te that streets should be kept
about two feet low during rough grading to ~ccommodate
the pavement sections. Please not.e that these ·pavement
sections may not be the final ones used and that actual
sections will vary across the site. R-valuetests
should be performed after grading for final design of
pavement sections., The pavement subgrades should be
prepared as recommended in Section 7.2.3-and compacted
to at least 90 percent of the Modified Proctor maximum
dry density (ASTM D 1557-78). Aggregate bas'e course
should conform to the CALTRANS Standard Specifi'cations
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Centre Development
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Job No. 05-4879-011-0·0-00
Log No.8-l797
Page 36
for Class II base, and should be compact'ed to a minimum
relative compaction of 95 percent.
If rigid pavements are required at loading docks or
trash enclosures, we recommend a full-depth Portland
cement concrete section with a minimum thickness of six
inches. The'concrete should be durable andr'~sistatlt
to scaling, wi.th a modulus of rupture equal to at least
600 pounds per square foot. We further recommend that
113 deformed steel reinforcement bars be placed on 18 ...
inch centers in both directions for crack control.
Steel dowels should be installed at all cold joints,
and contraction joints should be placed at spacings of
25 feet.
7.9 Review of Grading Plan's
San Diego Geotechnical Consultants should review the
grading plans for the proposed development p.rior to
construction. This review will allow us to as~ess the
compatibility of those plans with the recommendations
in this report. If the final plans differ materially
from our present understanding of the project, further
investigation and analysis or recommendations for
design changes may be necessary.
8.0 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, expresse.d or
implied, is made as to the conclusions and professional
advice included in this r.eport.
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C'entre Development
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Log No. 8-1797
Page 37
The samples taken and used for testing and the observations
made are believed typi.cal of the entire project. However,
soil and geologic conditions can vary significantly between
drillholes, test pits, or other exploration l09ations. As
in:most projects involving earthwork, the conditions
revealed by excavation during cons.tructio'n may vary frolIl
those:predicted in our preliminary findings. 'If sucb·
changed· conditions are found, they should be evaluated by
the project soils engineer and geologist. It may then be
necessary to adjust the project designs or to recomm.end
alternate designs.
This report is issued with the understanding that the owner,
or his representative, is responsible for bringing the
information and recommendations contained herein t.O the
att,ention of the architects 'and engineers involved in the
project. The owner or his representative is also
responsible for assuring that the information and
recommendations are incorporated into the plans, and that
the necessary steps are taken to see that the contractor and
subcontractors carry out the recommendations in the fieid.
This firm does not practice or consult in the field of
safety engineering. We do not direct the contractor's
operat'ions, and we cannot be responsible for anyone other
than our own personnel on the jobsite. Therefore, the
safety of other persons at the jobsi.te is the responsibility
of the contractor. The contracto,r should notify the oWner
promptly if he considers any of the recommendations in this
letter to be unsafe.
Our f,indings in this report are valid as c;>f the date of
issue. However, changes in the condition of a site can
occur with the passage of time, due either to natural
processes or the works of man on this or adjacent
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Centre Development
July 29, 1988
Job No. 05-4879-011~crO-OO
Log No. 8-1797
Page 38
properties. In addition, changes to the applicable or
appropriate laws, regulations, and standards of practice may
occur as a result of either new legislation or the
broadening of knowledge. Our findings may be invalidated
wholly or in part by such changes, over which we have no
control. The validity of this report the.refore should not t .
~e relied upon after a period of three years without a
comprehensive review by San Diego GeotechnicalCbnsultants.
1
***
SAN DIEGO GEOTECHNICAL CONSULTANTS, INC.
PoJ~ ... u. Q I d~
Patrick A. Thomas
Staf-f Geologist
~
Richard N.Mor is, P.E~ & C.E.G.
P.E. C 43422, Registration Expi.res:
C. E. G. 1355, Regis.tration Expires:
Senior Engineer
Cl;i~~
Anthony F. Belfast, P.E.
principal Engineer
PAT/RNM/AFB/rm/pb
6-30':"92
6-30-90
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APPENDIX A I' References
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References
1. H. V. Lawmaster & Company, Inc., 1980, Preliminary
Geotechnical Investigation, Proposed Palomar Business
Park, North San Diego County, California: Unpubl~shed
,report no. 79-9394/654G to Palomar Business Park, January
15, 1980 (includes grading plan review l.etters dated June
8, 19·82. and September 27, 1982).
2.. Moo·re & Taber, 1987, Report of Geotechnical Services,
Carlsbad Tract No. 81-46, Airport Business Center,tJnit
No.1, City of Carlsbad, California: Unpublished repo.rt
to Centre Development Company, February 25, 1987.
3. Bonilla, M. G., 1970, Surface Faulting and Related Effects,
in Wiegel, R. L. (ed.), Earthquake Engineering: Engle-
wood Cliffs, New Jersey, Prentice-Hall, p.47-74.
4. Seed.,. H. B., and Idriss., I. M., 1982, Ground motion~ and soil
liquefaction during earthquakes, Earthquak~·Engi.n~ering
Research Insti.tute, Monograph Series.
5. Ploes·sel, M. R., and Slosson, J. E., 1974, Repeatable high
ground accelerations from earthquakes, California
Geology, September.
6. California Division of Mines and Geology, 197'5, Recommended
Guidelines for Determining the Maximum Credi.ble and the
Maximum Probable Earthquakes: California Div;Lsion of
Mines and Geology Notes, Number 43~
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APPENDIX B
Field Exploration
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DEFINI'TION: OF~"TERMS~.
PRIMARY. DIVISIONS" SYMBOLS -SECONDARY' DIVISIONS
GRAVElS
MORE THAN.,
HALF' OF<
COAR8E~.
FRACTION~ ,IS '
LARGER THAN,
NO~ 4 SIEVE'
SANDS:'
MORE"THAN,,:
HALF OF"
GRAVElS
(LESS THAN
5 .. FINES)· Poorly 'gr.d.d,.gr.v.la~or gt..v ...... and"mlxtur ... , uttle'or no'fMe~, ' ,
Slty, grevela .. gr.ve" ........... mlxtur ••• non-pt.etlc ' , tln.a;-?"
dOAR8E~ r-----~--~~~--~----------------------------------~~' FRACTION,,18:
SIL TS'-AND-CLA VS"
LIQUID LIMIT IS
LESS THAN, 50 ..
SIIty" •• ndao:; a.nd-!allt~mlxtur •• ;:,non-ptaetlc·,f""""':,,·
... "Jnolrg81rHc:.,a,~lIlaj mllO.CI.o,.a or dlatoMe.oue" flne"eaildy'
SILTS AND' CLAYS' . LLD:=~.!!!!J~~!'!!~!'!!!'!=--------......:.-~
LIQUID, LIMIT IS'd
GRE·ATER"'THAN'~50"~: '
HI G H LV 0 R G ANI C. SOl L S.~·, P t, P.at!land~oth""hlohly· organic: .ol".,~.
rs AND CLA COBBtES BOULDERS
200 4 3/4-3
CLEAR SQUARE SIEVE OPENINGS
GROUNDWATER LEVEL AT TIME OF DRILLING.
GROUNDWATER L'EVEL MEASURED LATER IN STANDPIPE.
[I" LOCATION OF SAMPLE TAKEN U8ING, A STAND'ARD: SPUT !UBE SAMPLER.
, ~ .. ,. 2-INCH 0.0., 1-3/8-INCH 1.0. DRIVEN WITI ..... A 140'POUND H'AMMER'FAL'i.iNG"
30-INCHES.
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LOCATION OF SAMPLE TAKEN.U8ING' A MODIFIED'CALIFO'FtNIA 8AMPLE,.,
3-1I8-INCH' O.D •• WITH'2-1/2-INCH '1.0. LINER"R,ING8i DRIVEN U81NG THE
WEIGHT OF KELLY BAR (LARGE:,DIAMETER·BORINGS) OR USING A 140 POUND , ,
HAMMER FALLING 30-INCHE8 (SMALL D:IAMETERBORING):
LOCATION OF SAMPLE TAKEtf ,USING·· A 3-INCHO.D. THIN-WALLED TUBE 8AMPlER,
(SHELBY TUBE) ,HYDRAULICALLY PUSHED.-..
LOCATION OF BULK SAMPLE TAKEN· FROM, AUGER CUTTINGS.
KEY TO LOGS -UNIFIED:.,SOI1.:~CLASSIFICATION; SYSTEM. (ASTM 0-248,7)
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, DATE,OBSER¥EDr' 6-30-88 METHOD>·OF DRILLING:
LOG:,:OF~'BORING~ NO~ 1
Sheet 1 of 2
OESCfUPTJ:ON
TOPSOIL: Medium brown clayey SAND,
dry to damp, loose, fine grained' ,
SANTIAGO FORMATION (Tsa): Light
, brown: silty SANDSTONE'; damp to moist"
dense" orange: ,iron oxide staining':,
(mottled), fine, grained"laminated,~
moderately' weathered,. friable, N20E/20E
@ 6' remolded clay seam about 3" thick,
some' caliche, clay is dark olive-gray,
moist, spft to firm, NSOE/3S, wavey
@ S' sandstone becomes light grey with '
=-I----1-.,.---f, yellow sulfide stain" changes to sandy silt
'CONTACT: N40W/9S
Olive-grey sandy CLA YSTONE, damp to
moist, firm to stiff,. orange-red iron'oxide
.",.-4---I---+-staining: and·, yellow sulfide' staining. ,
CONTACT: NSOE/IO NW
Medium brown clayey SANDSTONE, damp
to moist, 'medium dense, fine grained, some
gypsum in fractures
~+---t---"" @ 15.5 joint fracture, N25W 55 SW
@ 19.0' Remolded clay seam about 3"
thick, ,olive-gray sandy clay with iron
stain, N50W 5
Light grey silty SANDSTO~, damp to
moist, dense to very dense, fine grained,
thin bedded to laminated" moderately
weathered, well indurated, sulfide staining
@ 25' becomes medium brown to light
grey, cross laminae N90E S S
@ 2S.5' gypsum seam, 1/2" thick,
continuous, horizontaJ.
@ 30' less brown coloration; mostly light
olive-grey, cross laminae (sulfide and iron
oxide stained) NSOE 10 NW
@ 35' dark grey sandy CLAY, damp to
moist" very dense to hard, very fine
'--"l~.~"'''''W' some yellow sulfide stain,
Ull~UAlUU:,~U, slab fracture, during grilling"
fracture N50E 80 W, drilling becomes. more
SOJ:L TEST
Atterbetg Limits
Expansion Index
.lnc~
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J)ATE. OBSERVED: 6-30-88 METHOD; OF DRILLING: 30" Bucket Auger
,0'-24':2218 Ib; 24~':'44':lj58 Ib.
LOGGED BY: 'PAT ,GROUND ELEVATION:-298'.0' LOCATION: See Geotechnical Man
" c w " ,~u. ,/ij I-I Z ! ILl !, 1Ll~ CO LOG:' OF;~ BORING', NO. 1 w '! II
0:" Q.
U. U.O ':J w" HH
't; I « 1-1-Sheet 2 of 2 " 1#)1-,. I#) I#)Z , ~)o SOIL TEST
l: ~<a:: ~~:it HILl, ' .... t:i
I-.... 0 ,,9 H., o~ Q. O,H "~ 5 ,D.(/) DESCRIPTION 2:0 , ZZ ILl II II 0 H~ Q 1-40 . \Minor seel?age at 39' I
,
-
-Total Depth:, 40!
-Minor seepage at .39"
.,. No Caving .
45-Geologically logged:. to 39'
Backfilled 6-30--88 -
-
-'
-
50-
-
-
-
-.
55-
'-
-
-
-
60-
-
-
-'
-
65-
-
,-
-
-
70-
-
-
---
15-
-
-
-,
--I ~~J; J'~9:h .00,.001' San: Diego'Geotechnical-Consultant$" Inc~ 1,lf1GURE: B-3 -4879~ 111--, ,,' .
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DATE
35
LOG OF BORING~~NO~ 2
Sheet ,-1 of 1
DESCRZPTZON·
TOPSOIL: Dark brown'sandy CLAY,
moist, soft to stiff
SANTIAGO FORMA TION.(Tsa): ,Ught-
olive-gray to medium: brown· sandy: silty
19.9 00.0 CLAYSTONE, moist,.firm'.to ,stiff~
massive, orange iron oxide~staining, some -
cobbles and gravel,. mottled, slightly
fractured -weathered to about 9'
@ 9' joint set N23W 50 N to N90W 75 SE
~+---+---h CONTACT: Horizontal
Light brown silty SANDSTONE, damp,
dense to very dense, fine grained,-
f ossilif erous
@ 11' fossiliferous.'Zone'·.
~+---I---h @ 12' crossbedded-sandstone dipping 5
degrees ± to SW; S 15 W
@ 13' clay seam'· horizontaL
ACT: N60W, IS S, gypsum filling -
@ 16' Olive-gray' sandy CLAYSTONE,
moist, stiff, some brown color
@ 20' some iron oxide and sulfide staining
and gypsum concretion
~+---+---h @ 25' fossiliferous· cemented zone about 6"
thick, gypsum at contact
Dark grey sandy CLA YSTONE~ damp to .
moist, very hard, fossiliferous, slab
f",.:-4---I----h fracture during dllilling, unoxidized, well
indurated
LU'JLUI.lllJ<; becomes more difficult; near
Total Depth: 30'
No Water
No Caving
Geologically logged to 30'
Backfilled 6-30-88
San Geotechnical,,: Cons····'-_·
SOIL. TEST
. Direct Shear; Sieve
Analysis, Atterberg.
Limits
Sulfate
Expansion Index
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DATE OlJSERVED:' 6-30-88 METHOD ,OF "'~ALf .. ,.u'''IJ._~--:!::!.~~!:!.!!l~_~ __ -'--_1
c ,...
w' w~ ~1iJ IX v'
::l.J ::l ... ... 11. "'z .,Z: (/)w
H<I: ~ H ... i" .J Oz
::l Z:o
::l m 0 Z H
ELEVATION: 280' ,
, LOG:cOF'BORING',-NO. 3
Sheet I of I
DESCRZPTION
TOPSOIL: Medium brown, to dark olive
gray CLA Y, damp to very moist:, soft, to
firm
CONTACT: gradational, caliche infilled, ~~~~~-+-~---h ,lOS '
SANTIAGO FORMA nON (Tsa): Light
olive gray white to light brown silty
SANDSTONE, damp to moist, dense, fine
to medium grained, orangeiton oxide
staining, moderately weathered, . massive,
friable, cross bedded
@ 9' cross laminae, iron oxide stained, N-S
15 E, fracture, caliche infilled, N-S 73 E
@ 14'clay seam 'about 2"-3" thick, caliche
18.5 07.0 infilled, slightly undulating
ACT: generally horizontal,
Olive-gray clayey SANDSTONE, damp'to
moist, very dense, fine-grained, iron oxide
mottling, well igdurated
@ 18' clay seam, ~"-3" thick, remolded,
wet, generally horizontal
@ 20.5' clay seam slightly remolded at
sandstone contact, horizontal
@ 23' clay bed
@ 30' gypsum concretions, dark charcoal
brown with caliche infilled fractures and
iron oxide borders
Total Depth 35'
Geologically Logged to 35'
No Caving
No Seepage
".1 JII~gn ... (2(!!ot.~chlnicakCoi1sulta
SOIL TEST
Direct Shear, Sieve
Analysis
Inc.-
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DATE OBSERVED: 6-28-88 METHOD"OF DRILLING:--!=!~~~~~~~-:-----,-'---'--I
Z H
,ELEVATION:-
LOG:OF"BORING' NO.4
Sheet I of 2
DESCRIPTION
FILL; Medium: brown SAND, dry to
damp, loose ,to medium dense, fine grained
ALLUVIUM (Oal): Medium brown
clayey SAND, moist, stiff
SOIL TEST
10.8 97.0 Consolidation, Sieve
Analysi$, Atterberg
Limits
f..,.,--t---t---t - - - - - - - - - - - - - - - - - - - - - - - - - - - -_. Medium brown clayey SAND, damp,
medium dense, fine grained
Sampler bouncing on quartz gravel clast
35'-38'
Inc •.
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DATE .OBSERVED:·· 6-28-88 METHOD OF DRILLING:~.,...==~=~~~--'----I
SS
60
6S
LOG OF: BORING: NO. 4
Sheet-2 of 2
DESCRIPTION
damp· to moist, very dense, fine· grained,
micaceous
Total Depth: 42'
No Water
Backfilled 6-28,..88
. San Consultants
SOIL tEST
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I-tLi w I&. .....
:1-
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i-I Z ,8 1&.0 HH II,; ~,~ . " -G)-
<l:fJ 3
.;J:H 9 ()
II Z H
LOG OF'BORING~NO .. BW-l
Sheet-1 of' 2
DESCRIPTION
COLLUVIUM: -Medium brown SAND, -+.r~f--+--I!--+--+---h dry to damp, loose, 'fine ·grained
SANTIAGO FORMATION (Tsal:: Light:
brown SANDSTONE, 4amp, dense,. fine--
grained, some ·silt. -,
Dark gray CLA YSTONE, damp to moist,
firm to stiff .
@ 36' Medium brown CLA YSTONE,. moist
to wet, soft to firm
Dark grey CLAYSTONE, moist, very dense
San 'J'IFI~l7n:, GeotechnicalConsultants,Jnc.,
SOIL TEST
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SS
6S
10
7S
San-
LOCATION:
LOG-OF BORING,NO;. BW-l
Sheet 2 of 2
DESCRIPTION
Total Depth: 51'
No Caving
Seepage @ 36'
Well Installed 6-28-88 by' Hydrotech. All
samples by Hydrotech.
SOIL TEST
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DATE' VD':).Il.,ft
20
25
35
San,:
METHOD OF DRILLING:~~~~~~~~'""'---_-""';I
LOG OF BORING'NO.-,BW-2
Sheet 1 of 1
DESCRIPTION
FILL: Medium ·brown SAND, dry to
damp, loose, fine grained
ALLUVIUM (Q31): Dark brown sandy
CLAY, moist to wet, soft, strong petroleum
odor
SANTIAGO FORMATION (Tsa):
Olive-gray CLA YSTONE, moist~ soft to
firm, some yellow staining
Total Depth: 16.5
No Water
Well installed 6-28-88 by Hydrotech
,Geotechnical· Consultants, Inc.
SOIL,. TEST
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DATE OBSERVED: 6-28-88
LOG OF::BORING:NO. BW-3
Sheet 1 of 1
DESCRl:PTl:ON
FILL: Medium brown SAND, dry to
damp, loose, some· roots and organic debris,
fine grained
ME~al1Llm gray to
medium brown clayey· SAND, moist, loose,
some gravel, fine grai~ed
Medium brown to medium grey
SANDSTONE, moist to wet, medium dense,
some orange staining, fine grained
Total Depth: 1.5'
Water @ 11'
Well installed 6-28-88 by Hydrotech
San; Uif:!!llo:'Geotechnical Consultants, lilc.
SOl:L TEST
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DATE OBSERVED: 6-21-88 , METHOD' ,OF DRILLlNG:-·, Kubota i<H 170L Trackeq Hoe
LOGGED BY: PAT GROUND' ELEVATION:' 248' ± ,LOCATION:" See Geot~chn1cal Map ..
~ >-
, -I-III -ti 0 ~ a: I&. i= 0 III ... 111-" of TEST PIT' NO. 1 III C 0 llliU Do a: I-I&. Q u. a: ... :::E =»z 111--ii: .... =»Do c 1-111 Q>
i= ~ I-:::E '~ ~I-cl-SOIL-, TEST ij ~ ~c ~ oz-... e;; Do ~ 0 AoZ III C o~ ' ... :::EO DESCRIPTION---... z, Q Q 'III 0 ... III =» 10 Q III
' -
• ..!M I---.,..-------ALLUVIUM (Qa1): Light' brown SAND,"
SC \ damp, loose, fine gr~ined, "some rip-2' · rap' and debris on surface · -' , ----'--Dark grey sandy CLAY, wet, soft, some ·
5-
seepage at 2-3', strong' petroleum,
odor ·
--------_ .... ---
-CL ~ SANTIAGO FORMATION (Tsa) , Olive-gray
sandy CLAYSTONE, moist to wet, soft
10-to firm, some yellow-orange staining -
·
.: Total Depth: 8'
· No Caving
Seepage at 2'
15-" Backfilled 6-2,1-88 ·
.
LOGGED BY: ,PAT ,GROUND ELEVATION:. 240' ± See' Geotechnical Map .LOCATION:'
TEST PIT NO. 2
ALLUVIUM (Qal): Medium brown clayey
SAND, damp to wet, loose, fine
grained
SC -
5-~
Expansion Index
Seepage at 6'-13' ·
·
10-
·
CL SANTI~GD FORMATION (Tsa): Olive-gray
~SandY CLAYSTONE, damp, soft to firm
15-Total Depth: 13' -seepage at 6-13'
caving
Backf111ed 6-21-88
JOB NO·:06-4879-0 11-00-00 lLOG OF"TEST PIT I FIGURE: B-1 2 -., --
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DATE' OBSERVED:' 6-21-88 -METHOD, OF DRILLING"" Kubota KH 170L Tracked Hoe
-
-LOGGED' BY: PAT GROUND,ELEVATION:' 264' ± ,LOCATION:--See Geotechnical MaE
" ~ >ii: -t-W -I-0-# CCo w ;::: 0 w -' w_, TEST' PIT-NO. S w 4( ,0 IIIW Go. a:t-o Go.
I&. 0 I&. a:-, :E ez w--ii: .... :;)Go. 4( 0> '+ co t-:E co cow, ct:: SOIL TEST ~ ~" -t-.... !4( :.:: Oz~ -'co Go. co 0 oco ,-' :EO, Go.z W 4( -' z !) 'w DESCRIPTION'\ 0' -' III !) III 0 10 0 -· .. ALLUVIUM (Oa1) : Medium brown silty
, SAND,_ dry to damp, loose, some roots
SM ~and organic debris, fine grained
· SANTIAGO FORMATION (Tsa) : Light brown
&~ SANDSTONE, damp to moist, medium
· dense to dense, fine grained, some
". orange staining
SM -
10--Total Depth: 9' .. No water -No Caving
-
1&-"
· ,
,
.
-LOGGED BY: PAT ,GROUND. ELEVATION:, 272' ± LOCATION: See Geotechnical' 'Map
TEST' PIT NO. 4
--. '.
ALLUVIUM (Qal) : Medi um brown silty
SM SAND, dry to damp, loose, fine
grained
·
& SANTIAGO FO~TION (Tsa) : Medium
brown silty SANDSTONE, damp, me~ium · SM dense to dense, fine grained, some · orange staining
·
U,....
Total Depth: 9.5'
No water -No Caving
1&--
-,
JOB NO'=OS,-4819-'O 11-00~oo,ILOG-OF· TEST" ·PIT ' , TFIOURE:·S ..... 13 .. . --
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DATE' OBSERVED:" 6-21-88 METHOD OF DRILLING: KUbota KH l70L Tracked Hoe
,
LOGGED BY: PAT' GROUND' ELEVATION:' 290.1 + LOCATION:' .See Geotechnical MaE -~ I-W ->-I-.0' w~ leU.
W ;: 0 w .... of TEST" PIT NO. g w c 0 IIlw A. §I-U. () U. Ie ... :IE w--.... :::tA. C I-Z (»
i= . Ii: cr) I-:E cr) cr)W' cl-SOIL. TEST ;; :t fec. -.... ... -~ OZ Go" A. cr) 0 ocr) ... :EO .. z w c' ... Z :::t () 'zw DESCRIPTION, 0 ... III :::t III -0 ().
TOPSOIL: Dark brown sandy CLAY, damp
SC to moist, soft ·
. SANTIAGO FORMATION (Tsa) : Light brown -
5-silty SANDSTONE, damp to moist,
medium. dense to dense, some orange -SM' staining, fine grained --
10.., .
-Total Depth: 9 1
No water -
.; NO Caving
-
15-'"
·
I
LOGGED: BY: PAT GROUND ELEVATION:. 278 1 ± .LOCATION:" See Geqtechhical Map
TEST' PIT NO. § -.
ALLUVIUM (Qal) : Dark brown clayey
SC ~. SAND, damp to wet, loose to firm,
· fine grained
-SANTIAGO FORMATION (Tsa) : Light brown
5-· ~ SANDSTONE, damp to moist, dense to
SM very dense, fine grained, some orange Maximum density,
-, staining Direct Shear.,
Sieve Anaiysb
10-Total Depth: 8 1
No Water
No Caving -Backfilled 6-21-88 -
15---
JOB· NO.:0.6-48 79;"011-00-00 ·llOG .. OF TEST PIT' I FIGURE:' B -1-4 .
~ .. ,
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. DATE OB8ERVED:' 6-21-88 METHOD OF DRILLING: Kubota KH 17.0L Tracked 'Hoe, -W/24i~
LOGGED ,BY: PAT GROUND ELEVATION:' 250'±' LOCATION: See Geotechnical Ma12 ." .... a t-w .... )0 ....
t-Q w! cz:1&. ,w, i= 0 ':w .... Qf TeST PIT-NO. 7 w < 0 IIIW a. CZ:t-I&. u ,I&. cz: .... '::1 =z w--... < a> Ii: 4J) .=a. t-w SOIL TEST' i= t-::I 4J), !!t-<t-eo .~ !!< ¥ Oz. .... i; a. 4J) 0 Q4J) ' .... ::10, AoZ W < .., z = 'W DESCRIPTION Q .... III = III. a IQ u
~, ALLUVIUM (~a1) : Medium brown sandy
SC CLAY, damp' to II)Oist, soft to stiff
.
8 SM' rx SANTIAGO FORMATiON (Tsa) : Light
... ' ~ brown SANDSTONE, damp, dense to very
-dense, fine grained
-"
-
10-', Total Depth: 5'
-No Water
"
No Caving
"
"
18-. .
~
LOGGED BY: . fa~ ,GROUND ELEVATION:: 288' ± LOCATION: ' See Geotechnical Ma~ .
TEST PIT' NO. B
ALLUVIuM (Qa1) : Medium brown s~ndy
SC CLAY, damp to moist, soft to firm,
some gravel
8-
SM SANT+AGO FORMATION (Tsa.) : L.i,.<;Jht brown
to gray SANDSTONE, damp to moist.,
~dense to very dense, some oran~e . staining, fine grained
10--
Total Depth: 7'
No Water
18-No Caving
",
JOB NO':05 -4879":0 11-00-00 I LOG OF, TEST PIT ' IFIGURE:~ 8-15, -, ,
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DATE OBSERVED: 6-21-88 METHOD,OF DRILLING: KubotaKH<17.0L. Tracked Hoe W~24"
>l;,,...lr,,,,t-,-. -_ _ .
LOGGED'BY: f~ GROUND ELEVATION:-20~' + ,LOCATION:-S~~ ~~gt~S;;_bD;i."al l:1a~--~ I-W ->-l-ra #. eel&. w j: 0 ..I w_-ef TEST' PIT-NO. g w c 0 mw -Ao ce ... I&. U I&. ce..l 2 :::I Z w--Ii: .... :::lAo C "'w U>
i= C1) 1-2 ., !lI-e!:: SOIL TEST iii ~ !-C lII: OZ' ..IC1) Ao-., 0 e., '..I 20 AoZ W C ..I Z :::I 'w DESCRIPTION' e ..I m :::I m U Ie 'U
ALLUVIUM (Qa1): Medium brown silty
Sc. CLAY, damp to moist, soft to finn
·
&
· SM SANTIAGO FORMATION (Tsa):, Meqium
.. ~ brown SANDSTONE, damp to moist, dense
to very dense, fine grained · -
10-Total Depth: 6.5' -No Water
-No Caving
Backfilled 6-21-88 · ·
1&-'
· ·
,
~L~O:G:G:E~D:..:B~Y~:===..:G:R:O:U::N~D:..:E:!L_;.E:!V~A~T~IO~N=:===::!L:!:O~C~A~T!!:IO~N~:=====::::;:========I"
•
·
&-
10-~
· -
·
1&-
TEST' PIT NO.----.
J..:o:~~-"""""-"'---'-----'-"""------------_..&.._"'P!!'!''!''''!''!'!!~~--~--JOB NO·:05-4879-0 11-00-00 I LOG OF: TEST PIT IFIGtmE:"f;I-16 ~--~--~~--~~----~~~~~~~~~~----------.. -----~-
-.
-------------------
en o z o
() w UJ :::i ::! ~ -w ~
100
90-. TRUE VELOCITY
80 909 ft/.ec
70 3700 ft/.ec
80 11200 ft/.ec
DEPTH TO TOP OF LAYER'
BELOW A BE'LOW, B
..... ft 1.8 It
6.6 ft 13.6 It
PROBABLE MATERIA.L
SURFICIAL SOIL
WEATHERED BEDROCK
BEDROCK
(SANTIAGO PEAK VOLCANICS)
t= 60 ...
W > icC a: I-
o W > a: w UJ In o
JOB NO.:
.. 0
30
20
10
11200 ft/eec
120 .. 8 ft/eec
10528 ft/eec
700 It/eec
GEOPHONE SPACING:,10 FEET
.11238 ttl8ec
DISTANC~ TO GEOPHONE (FI;ET)
ORIENTATION: N900E SEE PLATE 1 FOR TRAYE'RSE LOC,ATioN
TRAVERSE' NO.: S -:-1
selSM,c TRAVERSE
95-4879-01"1-00-00 DATE: 'JULY 1988 fl~URE: 13-17
100
90
80
70
80
60
"0
30
20
, 10
0 I 200
-------------------
-CI) o z o
() w
CI) ::;
::! ~ -W ~ i= .... w ~ II: t-
O W > II:
W
CI)
In o
100
90'.TRUE VELOCITY DEPTH BELOW A DEPTH ·BELOW B
8l 1320 ft/sec
70 8300 ft/sec 5.8 ft 5.1 ft
80
60
40
30
20
10 .
PR.OBABLE MATERIAL
SURFICHAL SOIL
BEDROCK
(SANTIAGO PEAK VOLCANICS) I
100
90
80
70
80
50
40
30
20
10
0 --> r I-, 0 r I-1 1 I 200 . 1
100
f:$.
DISTANCE TOG~OpHONE (FEET)
GEOPHONE SPACING: 10 FEET
ORIENTATION: N7cPW SEE PLATE 1 FOR TRAVERSE LOCATION . :" . . .~
TRAVERSE NO.: S -2
SEISMIC TRAVERSE
~OB NO.: 05~4879-011-00-00 DATE: Jl)LV 1988 FIGURE: B-18
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APPENDIX C
Laboratory Testing Program
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Laborato,ry' T'esting Program,
Typical soil samples from the site were, tested to determine their
engineering properties. , The te'st ,methods usedconfQrm gene~ally
to those of the American Society for Testing and ,Ma,terials (AS'IM)
or those of other recognized st'andard-setting organizations. The
following section describes the testing program.
Clas s,if i ca tlon
During'fieldwork, the soil and, rock was classified ,by the Unified
Soil Classification System (v;i.su'al-manual proc:edure) of AS'rM D
2488-84,. These class ifications were checked and, if necessary,
modified on the basis of laboratory test resuLts (ASTM D 2487-
85) • The logs in Appendix B show the classific'ations.
Atterberg Limits
AS'IM .D 4318-84 was used to determ'ine the li;.quid limit" plastic,
limit; and plasticity index of three selected ,clayey samples.
FigureC-l shows the results.
Particle Size Analysis
Mechanical analyses of particle'-size distribution, as described
in ASTM D 422-63, were made on four selected sa1Ilples. Figures 0'-
2 through C-S show the results.
Direct Shear
Gonsolidated, drained, direct shear tests (AS'IM D 3080-72) were
made on two relatively undisturbed samples of Santiago Formation
rocks from drillholes B-2 and B-3. The test results are pl.otted
on Figure C-6. Tests were also made on a Santiago Formation
sample from test pit TP-6 that had been remolded to 90 percent of
the modified Proctor maximum dry density. The results of these
tests are shown on Figure C-7. All three tests wer~ made under
saturated conditions and were carried out to measure uitima,te
strength values.
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Consolidation Tests
Laboratory Testing Program.
(Continued)
To assess its compressibility when loaded and wetted, a sample 6f
alluvium from drillhole B-4 was subj~ctedto a consolidation test
(ASTM D 2435~80). Figure C-8 shows the. results.
Maximum Density/Optimum Moisture Content
The moisture -density rela,tionship for one sample of Santiago
Format;:ion rock from tes·t pit TP-6 was determined \ising ASTM D
1557-78. Table C-1 lists the test resuits.
Expansion
The e~pansion·potential of two samples of Santiago Formation rock
from drillholes B-1 and B-3, and of one sample o£ sUl='ficial soil
from test pit TP-6, was tested using theUBC 29-2 expansi.on index
method. Table C-2 lists the results.
Sulfate Content
A sample of Santiago Formation rock from drillhole;B-2 was tested
for w~ter-soluble sulfate minerals with CALTRANS Method 417 (Part
I). The results are listed in Table C-3.
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PLASTICITY CHART
80 V ,~ 50 V -CH ,~ 'it -X .. 0 .~
w / V Q CL Z' ->-30 "
I-~ -24 () -" MHoo 1-' ~ 0 20 or
4( /' OH ..J a. .y
10
7 ~---V .. CL-ML ;L////// ML lOL 1------ML, /'" 0 0 10 20 30 .. 0 50 80 70 80 80 100
LIQUID LIMIT' (tJU
'UNIFIED
8AMPlE' ,NATURAL LIQUID', PLA8-' PA88ING, LIQUIDITY 80lL
8YMBOL BORING' DEPTH, WATER' LIMIT' TICITY NO. 200 INDEX CLA881-' NO. CONTENT INDEX 8IEVE, (FEET) (") (") (", (") (") FICATION
8YMB~L
8.0-1 1 -50.7 23.7 --CH 8.2
2 2 5.0-18.8 "8.8 2".8 8$.9 -0.1'9 CL 8.0
3 .. 20.0-10.8 33.1 13.5 37.3 -0.85 8C 22.0
,
,
ATTERBERG LIMITS
JOB NO.: IDATE:, IFIGURE: '
05-4879-011-00-00 , 0-1,
"
,
~ ..
"
-------------------
~
0 0
01-
I.Z ~o Q) I. ....
(D
I
0 ..,.
..4
I
0
0
I
0
0
I
'lJ >-::D -!-I -0 r
'" en -N m
> Z > r -< en en
t-:n1.
,is c: :It oP.'
I
f\)
"G m :It () m Z ~
"G > CIl CIl
2 Ii)
GRAVEL SAND
COARSE MEDIUM .-' FINE SILT CLAY
SIEVE SIZ-=S-U.8. $TANDARD
3/4" 112" 1/4"" 4 10 20 40 100 200
100 ~ I I11I11 III ~, I1111 T I II T" "i'J' 11111 "I II -I11I I I III 1
100
80 80
80 80
70 II I I I I I II I I I H I III I I I II I I III I I I I I I I I I I 170
eo II I I I I II I I I II I III I I II I I I II I I I I I I 180 ~ .
() m Z
50 II I 1 I I I II I I I If 1 III I I II -I I I I" I I I I 1 I 150 ~
> CIl
CIl
4011 111111111 II 1111111.11 111111 I· 11111 1402
3011 I I I I 1.11 I I I II I III I I I II 1 I I II I I I I I I I I I I I 30
20 II . I I I I t II I I I II -I III I I I II . I I I II I I I I I I I I I . I .1 20
1011 I I I I' I II I 1 III I III I I I it I' I . I I I II I I I . I I I I I I I I I 110
o
10.0 1.0 0.1
PARTICLE SIZE...,t-tILLlMETERS
BORING NO~ I:DEPTH (FEET) I SYMBOL I LIQUID LlMITIP~ASTICITY ~~DEX
~01 .
CLASSIFIC~tION
2 5.0-8;0 • 49.81 24.9 CL-S,ANDY LEAN CLAY (SANTIAGO FMTN.)
--;0
.001
Ii)
--------------~----
Co. ~: :,..,P , ! ~
" :.-
::0 -I 5 r-"m r:' ,~
N "' > Z >-r-~ en
Cii
~ .,.
ii' c' z,
~W.
SAND GRAVEL C~AY SILT MEDIUM -I FINE . COARSE'
SIEVE 81~ES-U.8. 8TANDARD
3/4" 1/2" 1/4" 4 10 20 40 ' . 100 . 200 100'~1 111111 III I' ~ • III1 I t+=t I' I I I11I1 I I I III 1'1 I II ,100
00 II I 111111111 I I 111111 H N I I1111111 I I 1111 r I F I I I ..
80 II I 111111111 I f II If II AI I I "i 11111111 I I If 11111 I f 180
70 ' I I I II K , J I ILl 11 1.11 J 70
II , I I I II I "II l'
~ ~ ~ m~ ~m z z n n m ~ m z 11 Z ~~ ~~
~ l " :. ' II :.
• , I·' • • • • ~40 '~" 40~
>. ~
3011 I I. I I I II I I I II I III I I I II . I I I II I I I I I I I I I I I 30
20 II I I I I I II I I I I II I III I I I II I I I I II I I I I I I I I I I I I I 20
10 II I I I I I II II II II I III I I t II I . ' . I I I t it t I I I I· I I I I I 110
" I I' I "' II I I I J" I' II. .1 II I . . 'r ! .' . . _ 1'111 ~'II" I I., .1 10 0,. '.' , . . 1 . ' , .001
' • ! '0"1
'PARTICLE 8IZE-MILUMETERS
10.0 1.Q
BOfJIN~ NO.1 DEPTH (FE;EU I SYMBO~ I LIQUID ~IMITI PLA8TICI.TY INPEX 'CLA8SIFIQATIQ~ ,
3 15.0-18.0 • Sc-CLAYEY SAND (SANTIAGO FMTN.)
---~---------~--~--
c... o at
, I Z" o
I ~ ...
I o o I
;'.
o o ~
"'0 ,.
::0 ~ (5
r'
"" 'en N m , 1 > Z > r-oo(
(Jj
Cii
~ C5 c ~ '~m 1","" , I
! ...
SAND CLAY GRAVEL SILT MEDIUM FINE COARSE
SIEVE SIZES-U.S. 8TANDARD
10 20 40 100' 200
" :~~ ~IIIIIIII lIN 1i11~ll III 11111 fill I:
70ETlIIIIIIII I I I1I111111 '1\1 1 11111111 I I I111111 I I 170
"0 ~ "0 m 80 \ 80 m ~ ~ o 0
m l~ m Z ~ Z ~ 50 • 50 ~ : , :
~ ,~ ~ , ~ ~
Z40 -110. 40Z Q II' Q
30 II II I II" I I I " I III I I I " I ' -I I I" I I I I I I I I I I 130
20 II I I I I I II II I' I," I III I I I II I 'III I I" I I I I I I I ·1 . I I I '120
10 III ' I I I I" I I I " ,I 1111 I I " . I I I I II II I ·1 . I I I I I I I 1-110
. I I' '.1\ . , 'I" I' " I' 1,0 Q t' ,I I I " ". ' I I . '" I' " , ' . " " ; . . , .001 10'.0 .C)1 1.0 . 0~1
PARTICLE 8IiE-MILLlM~TER8 '
BORI,NG NO.1 DEPTH (FEET) ISY",BOI,.'1 L,IQUID '-IMITI P'-~STICITYINDEX
4 I 20.0-22.0 I. 33.11 13'.5
CLA~SIFICA'rION
'SC-CLAYE'( SAND ~ALLUVIUM)
~------~------~----
SAND CLAY GRAVEL SILT MEDIUM FIN~ COARSE
~IEVE ~IZES-U.8. tnANDARD
3/ .... 112" :II...... 10 20 .. 0 100200
100 II I III III I t I FiJ IIII II III 'I I 'I' I11II I I I III I I I· I 'I 1'00 .... ....
I
0 80/1 I 1111 ~ (" I r~ Irlll r=1 rl=l rntTT r=r=1 =11 ITrT+=1 I 180
0
I
0
0 ~ II IIIIIIIIIII! II [ltJ11 II 111I11111 I 11111111 I I::
80
70
"tJ > :u "D
-f m -:u 0 () ,r-m
m z -4
en "D -:.
N CoO rn CoO
, -
> Z fa
Z > r-oo( en -
80
50
"0
30
IL I I II ~I 'III 111111 I 1/ I II II'\. 1/ I I II ~ "D ~ ~m :u
I; 111:1 I; I I Ii '\ ,() II' I 1 I I I I. liT I R1 IT Iii I I 1;1 I m 1111 \ Z , 50 ~
\
' "D
Ii I II I I /I I :. n II I 1 1/ I I II ' I /I CoO I I 1/ \ !! J~ .. 0 i
IL I I 1/ 1/ I ' II I TilT 1/ I" I 1/ :: I I I I" I I I I ,I I I I I I I I I )J I I ~30
I'i en 20 II I I I I 1 II 1 1 1 1 II 1111 I I I II I I I II I' I I I I 'I II I I I I I I ' I 120
10 II 'I II I III II I I II 1,111 I I, I /I I I, i" I II il I I I I 1111 I I I II 110
0 1\ I' , '" "I " II" I I I, II , ' I I I "II I I' I I , , " 10
10.0 1:0 0~1 .01 .001
PARTICLE SiZE-MILLIMETERS
~ORI~G, NO., DEPTI1 (FEE'r>1 SYMBO-., I LlQUIQ LIMIT I PLASTICity INDEX CLASSIFICATION
T-8 I 5.0-8.0 '. 'SM-SllTV SAND ('SANTIA~O FMTN.)
.. -
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£ o A. .....
:z: I-Cl" Z W
BORING DEPTH COHESION, ANGLE OF I-___ ___:~SA:.:.:M::::=-:PL~E~D~E:.:.:S~C~R_::_'P_::::T~IO::.:N~--~ NO. (FEET) (PSF) FRICTION,O Ct"'S'AND,;o(fLE'AN CLAY
, 2 6.0-8.0' 80/0 37/33 (SAtnI-IcGO'.-FtNlttt,J, '
4000 TE,ST MADE ON
R,ELATIVELY
UNDISTURBED S,AMPLES
3000~-----~-----~-----_+-------~~---,~--+------~
~ 2000~'--------+-----~----~~-~~~----~--------+--------~
o
Cl' z a: < w :z: o
:z: I-
Cl' Z
W
BORING· NO.
1000 2000
510/40,0
4000 5000 .
30001-----~-------~-------~~~----~~~----~~~-~
00
~ 20001-----+-----~~-----_+~~:---~~------+_------~
o
Cl' Z a: ~ :z: o
1000 ...... -~~--~~------~--------+-------~~--------+------~
°0~------,~0~0~0-----~2~00~0~------:3~0~0~0------~4~00~0~--~~5~0~0~0~~--~800·0
NORMAL LOAD (PSF)
SHEARING STRENGTH TEST FIGURE:, 0-6
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~ en Q" ....
:r: t-CJ Z W II: t-en
CJ z' a;
C w :r: en
.... t.I. en
Q" .... :c t-
CJ Z W II: t-en
CJ Z a;
C w :r: en
BORING . NO. DEPTH COHESION. ANGLE, 01(, I-__ ... S::.:A:.:.:M::::P:...:L:,::E~D~E:;.SC~R;:;I;:..P~T~IO~N':"-___ -I
(FEET) (PSF) FRICTION. S MJ""S I L T Y SAN 0
T-8 6.0 -8.0 ... 8 0 12 3 0 ' 2 9/2 9
... 000 ,AMP-LES REMOLDED T
90. OF MOD. PROCTOR AX., DRY DENSITY
3000
2000
1000
AT AEJO'UT OPTIMUM
MO'ISTURE CONTENT
(SANTIAGO FMTN.)
°0~---~100~0~.------~2~0~00~----~3~0~0~0~.-----~"'~00~0~,.-----~6~O~O~O~' ----~8000:
NORMAL LOAD (PSF)-'
BORING DEPTH COHESION. ANGLE. OF SAMPI:.E·DESCRIPTION NO • (FEET) (PSF) . FRICTION.o ..
... 000
3000
2000
1000
1000 20PO 3000 ... 000 6000 EJOOO
NORMAL LOAD (PSF)
SHEARING STRENGTH TEST
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.... ---Z 0 0 z < A.
)( w
8.0
4.0
2.0
BORING NO • ....£.. '
SAMPLE DEPTH 20.0'-22:£0..:.
INITIAL DENSITY (PCF) 98.7 EXPlANA'f;ION
INITIAL MOISTURE (1ft) 10.8 FIELD MOISTURE
FiNAL MOISTURE (1ft) 1 9.8
----------SAMPLE SATURATED
INITIAL VOID RATIO 0.71 0
REBOUND
20.00=-~~0:-~0~±0-±0~~~0~--~'~0~~0~0~~0~~~0~--~0~~0~0:-0:-~~0
0 0000 0 0000 0 0 ooo~ 0 ... CIt (1),..10 0 0000 0 0000 ... CIt (1),..10 0 0000 00 ... CIt (1),..10 ..
NORMAL lOAI) (P,SF) .
JOB NO.:. . I
05~4819-011-00-00 LOAD CONSOLIDATION TEST" , FIGURE:
.C-8
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TABLE C-l
MAXIMUM DENSITY/OPTIMUM MOISTURE RELATIONSHIPS
(ASTM D 1557-78)
Sample Maximum Dry Optimum Moisture
Loca.tion Density (pcf) , Content
TP-6
B-1
B-2
TP-6
@ 5.0-6.0 113.8
TABLE·C-2
RESULTS OF'EXPANSION TESTS
(UBC Method 29-2)
13.7
..
Sample Expansion ,Expans ion
Location Index Poten.tial
@
@
@
20.0'-21.0' 30 Low
30.0'-31.0' 24 Low
1.0'-2.0' 85 Medi,um
TABLE. C-3
RESULTS OF SOLUBLE SULFATE TESTS
(EPA 300)
(%)
Sample Location Soluble Sulfates (%)
B-2 @ 20.0'-21.0' 0.0797
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APPENDIX .D
Standard Guidelines for Grading Projects
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1 •
2.
STANDARD GUIDELINES FOR' GRADING PROJECTS'
GENERAL
1 .1 . Representatives of the Geo.technica1 Consultant should.
be present on-site during" gr:adingoperations in order
to make observations artd\perform,tests s'o that
, profe$s iona1 op inions can" be deve,loped. The 'opinion
will addres's whether. grad,i'ng has· proceeded. in
accordance with the, Geo'eechnicaLCansu1tant I s
. r,ecommendations and, appl'i-cable. project specifica·tions;
. If the site soil and geologic condit;ions are a·s
anticipated in the prelitIlinary-inves'tiga,tion; and if
additional recommendations are warranted by' any
unexpected site conditions:. Services do not· include
supervision or direction'of the· actual wark of the
contractor. his employees or agents.
1 • ~ The guidelines contained_. herein and the standard
details attached hereto repres·ent· this firm I s standard
recommendations for grad-ingand'other associated
.operations on construct:1on.··proj-ects.. These g~idelines
should be considered a portion of the repo.rt' to which
they are appended. .
1.3 All plates attached hereto shall be considered as part
of these guidelines.
l.4 'l'he Contractor should not vary from these gu1.d~lines
without prior recommendation by the Geotechnical
Consultant and the approval of the Client or his
authorized representative. '
1.5 These Standard Grading Guidelines and Standard Details
may be modified and/or superseded by recommendations
contained in the text of the preliminary geotechnical
report and/or subsequent reports.
1.6 If disputes arise out of. the interpretation of these
grading guidelines or standard details. the Geotech-
,nica1 Consultant should determine the appropriat.e
interpretation.
DEFINITIONS OF TERMS
2.1 ALLUVIUM --Unconsolidated detrital deposits resulting
from flow of water. including sediments deposited in
river beds, canyons. flood plains. lakes. fans at the
foot of slopes and estuari~s.
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Stanqard Guidelirtes
for Grading Projects
Page 2
2.2 AS-GRADED (AS-BUILT) --The surface and subsurf'ace
condi,tions at completion of grading.
2.3 BACKCUT' --A temporary construction slope at the rear
of' earth' retaining structures such as but.tresses,.
shear" keys ~ stabilization fills or retaini,ng walls.
2.4 BACKDRAIN --··Generally a pipe and gravel ors.imilar
drainage~ system' placed behind. earth retaining
structures"such,buttresses p stabi.lization fills~ and'
ret'aining . walls.
2.5 BEDROCK --·A more or less solid, relatively undis-
turbed rock in place either at the surface or beneath
superficial deposits of soil.
2.6 BENCH --A relatively level step and near vertical
rise exc'avated into sloping ground on which fill is to
be,placed.
2.7 BORROW, (Import) --Anyfi;LL mat'erial hauled to the
project site from off-site area's.
2.8 BUTTRESS FILL --A fill mass, the configuration of'
which is designed by engineering~alculations to
retain slope conditions containing adverse g~ologic
features. A buttress is generally specified by ,
minimum key width and depth and by maximum backcu.t
angle. A buttress normally contains a bac.kdrairtage
system.
2.9 CIVIL ENGINEER --The Registered Civil Engineer or
consulting firm'responsible for preparation of the
grading plans, surveying and verifying as-graded
topographic conditions.
2.10 COLLUVIUM --Generally loose deposits Usually found
near the base of slopes and brought there chiefly by
gravity through slope continuous downhi~l creep (also,
see Slope Wash).
2.11 COMPACTION --Is the densification of a f'ill by
mechanical means.
2.12 CONTRACTOR --A person or company tlnder contract or
otherwise retained by th~ Client to perform
demolation, grading and other site improvements.
." .. . ~-, .': -. -.
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Standard Guidelines
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2.13 DEBRIS --" All products of clearing r grubbing r demolitionr contaminated sotl, material unsuitable for'
reuse as compacted fill and/or any othe,r material $<;>
designated by the Geotechnical Consultant.
2.14 ENGINEERING,GEOLOGIST --A Geologist holding a valid
certificate-of registration in the spec~alty of
Engineering Geology.
2.15 ENGINEERED FILL_ --A fill of which the Geotechnical
Consultant" or' his representative. during graditlg-r ha·s
made sufficient tests to enable him to conclude that
the fill has been placed in substantial .. compliance
with the recommendations of the Geotechnical
Consultant and the governing agency requirements.
2.16 EROSION --The wearing away of the ground surface as a
result of the movement of wind. water. and/or ice.
2.17 EXCAVATION --The mechanical removal of e~rth
materials.
2.18 EXISTING GRADE --The ground surface config~ration
prior to grading.
2.19 FILL --Any deposits of soil. rock. soil-rock blends
or other similar materials placed by man.
2.20 FINISH GRADE --The ground surface configuration at
which time the surface elevations conform to the
approved plan.
2.21 GEOFABRIC --Any engineering textile utilized in
geotechnical applications including subgrade '
stabilization and filtering.
2.22 GEOLOGIST --A representat'i ve of the Geotechnical
Consultant educated and trained in the field of
geology.
2.23 GEOTECHNICAL CONSULTANT --The Geotechnical Engineer-
ing and Engineering Geology consulting-firm retained
to provide technical services for the Project. For
the purpose of these guidelines. observations by the
Geotechnical Consultant include observations by the
Geotechnical Engineer. Engineering Geologist and those
performed by persons employed by and responsible to
the Geotechnical Consultants.
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2.24 GEOTECHNICAL ENGINEER --A licensed Civil Engineer Who
applies scientific methods, engineering principle's and
professional experience to the acquisition, inter-
pretation and use of knowledge of materials of the
earth's crust for the evaluatton of engineering
problems. Geotechnical Engineering encompasses many-·
of the engineering aspects of soil mechanics, ~ock
mechanics, geology, geophysics, hydrology and related
sciences.
2.25 GRADING --. Any operation consisting of excavation,
filling or combinations thereof and associated
operations.
2.26 LANDSLIDE DEBRIS --Material, generally porous and of
low density, produced from instability of natural of
man-made slopes.
2.27 MAXIMUM DENSITY --Standard laboratory test .for
maximum dry unit weight.. Unless otherwise specified,
the maximum dry unit weight shall ·be determ~nec;l in·
accordance with ASTMMethod of Test D1557.
2.2-8 OPTIMUM MOISTURE --Test moisture content at the
maximum density.
2.29 'RELATIVE COMPACTION --The degree' of compactiQn
(expressed as a percentage) of dry unit weight of a
material as compared to the maximum dry unit weight of
the material.
2.30 ROUGH GRADE --The ground surface configurati.on at
which time the surface elevations approximately
conform to the approved plan.
2.31 SITE --The particular parcel of land where grading is
being performed.
2.32 SHEAR KEY --Similar to buttress, however, it is
generally constructed by excavating a slot within a
natural slope in order to stabilize the upper portion
of the slope without grading encroaching into the
lower portion of the slope •.
2.33 S·LOPE --Is an inclined ground surface the steepne,ss
of which is generally specified as a ratio of
horizontal:vertical (e.g., 2:1).
2.34 SLOPE WASH --Soil and/or rock material that has been
transported down a slope by mass wasting assisted by
runoff water not confined by channels (also se.e
Colluvium).
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3.
2.35 SOIL --Naturally occurring depQsits of sand, silt,
clay, etc., or combinations thereof.
2.36 SOIL ENGINEER --Licensed Civil Engineer experienced
in soil mechanics (alsocseecGeotechnical Engineer).
2.37 STABILIZATION FILL -_cA fill mass·,. the configuration
of' which is typically related. to.-slope he.ight and· is
specified by the standards. of practice· for enhancing
. the stability of locally advers.e· conditions •. A .
stabilization fill is normally specified by minimum',
key width and depth and .bymaximum b~ckcut angle. A
stabilization fill may orcm~y not haveca backdrainage
system specified.
2,; 38 SUBDRAIN --Generally a pipe and gravel or s imila.r
drainage system placed beneath a fill in the alignment
of canyons or former drainage channels.
2.39 SLOUGH --Loose, noncompacted fill material generated
during grading operations .•
2.40 TAILINGS --Nonengineered-fill which accumulates on or
adjacent to equipmentchaul-roads.
2.41 TERRACE --Relatively level step constructed in the
face of graded slope surface for drainage 'control and
maintenance purposes.
2.·42 TOPSOIL --The presumably fertile upper zone of soil
which is usually darker in color and loose.
2.43 WINDROW --A string of large rock buried Within
engineered fill in accordance with guidelines set
forth by the Geotechnical Consultan.t.
SITE PREPARATION
3.1
3.2
Clearing and grubbing should consist of the removal of
vegetation such as brush, grass, woods, stumps, trees,
roots to trees and otherwi'se deleterious natural
materials from the areas to be graded.Clea~ing and
grubbing should extend to the outside of all proposed
excavation and fill areas. '
Demolition should include removal of buildings, struc-
tures, foundations, reservoirs, utilities (including
underground pipelines, septic. tanks, leach fi.elda,
seepage pits, cisterns, mining shafts, tunnels, etc.)
and other man-made surface and subsu~face improvements
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4.
from' the areas to be graded. Demolition of utilities
should include proper capping and/or re-routing pipe-
lines at the proj ect perimeter and cllto.ff and capping
of wells in accordance-with the': ,requirements of the
governing authorities and the recommendat:ions of the
G.eotechnical Consultant at the time ,of demolition.
3.3 Debris generated during, clearing, grubb-ing and/or
. demolition operations' .. should. be wa·s·ted;' from areas to
be g'raded and disposed: off-site:. . Clearbig'" grubbing
and demolition "operations should be· performed under
the observation of the: GeotechnicaL Consultant.
SITE PROTECTION
4.1 The Contractor should be res'ponsible for' the stability
of all temporary excavations. Recommendations by the·
Geotechnical Consultant pertaining to temporary
e·xcavations (e.g., backcuts) are made in consideration
of stability of the comp'leted project. and, therefore,
. '. should not be considered ,to' prec;lude -the -res.pan8tbil-
. {ties of the Contractor. Recommendat.ions by the
Geotechnical Consultant should. not be considered to
preclude more restrictive requirement·s 'by the
regulating agencies. .
4.'2 Precautions should be taken during the performance' of
site clearing, excavations and grading to' protec~ the
work site from flooding, ponding or inundat-1on by poor
or improper surface drainage. Temporary provisions
should be made during the rainy season to adequately
direct surface drainage away from and off the work
site.
4.3 During periods of rainfall, the Geotechnical
Consultant should be kept informed by the Contractor
as to the nature of remedial or preventative work
being performed (e.g., pumpi-ng, placement -of sandbags
or plastic sheeting, other labor, dozing, etc~).
4.4 Following periods of rainfall, the Cortt.ractor should
contact the Geotechnical Consultant and arrange a -
review of the site in order to visually assess ~ain
related damage. The Geotechnical Consultant may alsQ
recommend excavations and testing in o.rder to .aid in
his assessments.
4.5 Rain related damage should be considered to include.
but may not be limited to, erQsion~ silting,
saturation, swelling, structural distress and other
adverse conditions id'entified by the· Geotechnical
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Consultant., Soil advers'ely affected should be
cl~s,sified as Unsuitable Materials, and should be
subject to overexcavat-ion and replacement with
compacted fill or other remedial grading,as
recommended by the Geotechnical Consultant.,
5. EXCAVATIONS" ------"'.,
5 .1
5.2
. ,
...;;;,U.;.;.NS;;;...;U;..;;,I;.;T_A-.,B_LE-.":..;;;.MA=' _T_ER .... I .... A-.,L_S ""
5.'1.1 Materials which ~re unsuitable should be,
excavated under 'observation and recommendations
of the Geotechnical. Consultant. Unsu,itable
materials include. but may not: be limited to,
dry, loose, soft, wet, organic compressible
natural soils and fractured, weathered, soft
bedrock and nonengineered or otherwise
deleterious fill materials.
5'.1 .2, Material. identified by the: Geot,echni,cal
Consultant as, unsa;-tisfactory due' to it's
moisture conditions should be overexcavated,
watered or dried, as needed, and thoroughly
blended to a uniform pear optimum'moisture
condition (as per guidelines reference 7.2.1)
prior to placement as compacted fill.
CUT-SLOPES
5.2.1 Unless otherwise recommended by the Geote~h
nical Consultant and approved by the regulating
agencies, permanent cut slopes should not be
steeper than 2:1 (horizontal:vertical).
5.2.2 If excavations for cut slopes expose loose,
cohesionless, significantly fractured or '
otherwise unsuitable material, overexcava,tion
and replacement of the unsuit'able materials
with a compacted stabilization fill should be
accomplished as recommended by the Geotechnical
Consultant. Unless otherwise specified by the
Geotechnical Consultant, stabilization fill
construction should conform to the requirements
of the Standard Details.,
5.2.3 The Geotechnical Consultant should review. cut
slopes during excavation. The Geotechnical
Consultant should be notified by the contractor
prior to beginning slope excav~tions. '
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5~2.4 If, during the course of grading~ adverse or
potentially adverse geotechnical conditions are
encountered which were not antt.cipa·ted in the
preliminary report··, the Geo.technical Consultant
should explore, analyze and make .recommen~
dations to treat these problems.
6. COMPACTED~ FILL.
All fill mater.ials should be compacted to at leas.t. 90
.percent of maximum density (ASTM D1557)tinless o.therwise
~eco'mmended by the Geotechnical Consultant •.
6 .. 1 PLACEMENT
6.1.1 Prior to placement of compacted fill, the
Contractor should request a review by the
Geotechnical Consultant of the exposed ground
surface. Unless otherwise recommended, the;
exposed ground surface should then be scarified
(6-inches.minimum), watered or dried as needed,
thoroughly blended. to achieve·near optimum .
moisture conditions, then thoroughly compac:ted
to a minimum o.f 90 percent of the maximum .
density.
6.1.2 Compacted fill should be placed in thin
horizontal lifts. Each lift should be watered
or dried as needed, blended to acnieve near
optimum moisture conditions then compacted by
mechanical methods to a minimum of 90 percent
of laboratory maximum dry density. Each lift
should be treated in a like manne,run·til the
desired finished grades are achie.ved.
6.1.3 When placing fill in horizontal lifts adjacent
to areas sloping steeper than 5: 1 . (hQrizon·tal:
vertical), horizontal keys and vertical benches
should be excavated into the adj.~cent slope
area. Keying and benching should be sufficient
to provide at least 6-foot wide benches and a
minimum of 4-feet of vertic'al bench height
within the firm natural ground, firm' bedrock or
engineered compacted fill. No compacted fil~
should be placed in an area subsequen.t to
keying and benching until the area has been
reviewed by the Geotechnical Consul.tant.
Material generated by the benching operation
should be moved sufficiently away from the
bench area to allow for the recommended review
of the hori.zontal bench prior to placement
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6.2
fill. Typical keying and benching detai,ls have
been included within the accompanying Standard
Details. .
6.1.4 Within a single fill area where grading
procedures dictate ,two or more separate,fills.
temporary slopes, (false slopes) may be, c:reated.
When placing fill adjacent to a fals,e', slope.
benching should 'be, conducted in' the S'atne manner
as above-described,.', At least a 3~foot, vert'ieal
bench should be -es.tablished' wi thin the firm~
core adj acent approved compa'cted-' fill, prior to
placement of additional fill. Benching should
proceed in at least 3-foot'vertical increments
until the desired finished grades, are achieved.
6.1.5 Fill should be tested for compliance with the
recommended relati,ve compaction and moisture'
conditions. Field density testing should
conform to accepted tes t methods. Dens! ty .
testing frequency'shouid be adequate for the
geotechnical consultant to provide. p.J;'of.e$sional
opinions regard'ings ·fill compaction and
adherence to recommendations •. Fill found. not
to be in conformance'with the grading·
recommendation should be removed or otherwise
handled as recommended by the Geotechnical.
Consultant.
6.1 .6 The Contractor should assist. the Geotechnical
Consultant and/or his representative by digging
test pits for removal det'erminations and/or for
testing compacted fill.
6.1.7 As recommended by the Geotechnical Consultant.
the Contractor may need to remove grading
equipment from an area being tested if
personnel safety is considered to 'be a prohlem.
MOISTURE
6.2.1 For field 'testing purposes "near opt'imum"
moisture will ,vary with material type and other
factors including compac.tion procedure. uNear
optimum" may be specifically recommended in
Preliminary Investigation Reports and/or may be
evaluated during grading.
6.2.2 Prior to placement of additional compacted fill
following an overnight or other grading delay.
the exposed surface or previously compacted
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6.3
fill should be, processed by scarifica'tion,
watered or dried as· needed, thoroughly blended
to near-optimum moisture conditions, then
recompacted t·o· a minimum of 90 percent of
laboratory maximum dry density. Where wet,
dry, or other unsuitable materials ,exist to
depths of grea·ter than ·one toot, the unsuita·b1e
materials should, be overexc·avated.
6.2.3 Following. a period·of flooding, rainfall or .
overwatering by other-means;, no additional fill
should be placed unti.l. damage assessments have
been made and remedial. grading performed as
described under Section'S.6 he·re.in.
FILL MATERIAL
6.3.1 Excavated on-site materials which are
cons idered sui.table to the Geotechnical
Consultant may be utiliz'ed as compac,ted fill;
provided trash, vegetat.ion and other
deleterious materials ar~ removedprfor to
placement.
6.3.2 Where import fill materials are required fO'r
use on-site, the Geotechnical Consultant' should
be notified in advance of importing, in order
to sample and test materials from propose9
borrow sites. No impo.rt fill mat'eria1s should
be delivered for use on-site without prio,r
sampling and testing notification by
Geotechnical Consultant.
6.3.3 Where oversized rock or similar irreducible
material is generated during grading, it: is
recommended, where practical, to waste such
material off-site or on-site in areas
designated as "nonstructural rock' disposal
areas". Rock placed in disposal areas should
be placed with sufficient fihes to fill
voids. The rock should be compacted in lifts
to an unyielding condition. The d.isposal area
should be covered with at least three feet o£·
compacted fill which. is free of oversized
material. The upper three feet should be
placed in accordance with the guidelines for'
compacted fill herein.
6.3.4 Rocks 12 inches in maximum dimension and
smaller may be utilized within the compacted
fill, provided they are placed in such a manner
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that nesting of the rock is avoided. Fill
should be placed and thoroughly compacted over
and around all rock. The amount of rock should
not exceed 40 percent by dry weight passing the
3/4-inch sieve_size. The 12-inch and 40
percent recommendations herein may vary as
field conditions dictate.
_ 6.3~5 Where rocks -or-similar irreducible materials of
greater than' 12 inches-but:-less than four feet-
of maximum-dimension are generated during
grading, or otherwise destred to be placed
within an engineered fill, specialhandi-ing in
accordance with the acc'omp'anyingStandard
Details is recommended. Rocks greater. than
four feet should be broken.down or disposed
off-site. Rocks up to four feet maximum
dimension should be placed below-the upper 10
feet of any fill and should not be clos·er than
20-feet· to any_ slope-face. -These recommen-·
dat-ions could vary as loca-tions of improvements
dictate-. Where'pr.actical, oversized. material
should not be placed below· areas' where
structures or deep utilities are proposed.
Oversized material should be-placed in windrows
on a clean, overexcavated'orunyielding
compacted fill or firm na·tural ground surface.
Select native or imported granular soil (S.E.
30 or higher) should be placed ahd thoroughly
flooded over and around all windrowed rock,
such that voids are filled. Windrows of
oversized material should be staggered so that
successive strata of oversized material are not
in the same vertical plane.
6.3.6 It may be possible to dispose of individual
larger rock as field conditions dictate and as
recommended by the Geotechnical Consultant at
the time of placement-.
6.3.7 The construction of a urock fill" consisting
primarily of rock fragments up to two feet in
maximum dimension with little soil material may
be feasible. Such material is typically_
generated on sites where extensive blasting is
required. Recommendations fo-r construction of
rock fills should be provided by the
Geotechnical Consultant on a site-specific
basis.
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Standard Guidelines
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6.3.8 During grading operations, placing and ml.Xl.ng
the materials from the cut and/or borrow areas
may result in soil mixtures which poss·ess
unique physical properties. Testing may be
required of samples obtained directly from the
fill areas in or.der to determine conforlilance·
with the specifications. Processing of these
additional samples ~ay take two or more working
days. The Contractor may elect to move the
operation to other' areas wi thin the proj ec,t, .or
mayo. continue, placing compacted' fill pending'
laboratory' and field test results. Should he
elect the second alternative; fill placed is
done so at the Contractor's risk.
6.3.9 Any fill placed in areas not previously
reviewed and evaluated by the Geotechnical
Consultant may require removal and recom-
paction. Determination of overexcavations
should be made upon review of field conditions
by the Geotechnical Consultant.
6.4 FILL SLOPES
6.4.1. Permanent fill slopes should not be constructed
steeper than 2:1 (horizontal to vertical),.
unless otherwise recommended by the Geotech-
nical Consultant and approved by the regula·ting
agencies.
6.4.2 Fill slopes should be compacted in acco'rdance
with these grading guidelines' and specific
report recommendations. Two methods: of slope
compaction are typically utilized in mass
grading, lateral over-building and cutting back,
and mechanical compaction to grad'e (i. e.
sheepsfoot roller backrolling). Constraints
such as height of slope, fill soil type_ access,
property lines, and available equipment will
influence the method of slope construction and
compaction. The geotechnicalc.onsultant should
be notified by the contractor what method wilt
be employed prior to slope construction.
Slopes utilizing over-building and cutting back
should be constructed utilizing horizontal fill
lifts (reference Section 6) with compaction
equipment working as close to the edge asprac-
tical. The amount of lateral over-building will
vary as field conditions dictiate. Compaction
testing of slope faces will be· required and
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Standard Guidelines
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Pa,ge 13
reconstruction of the slope may result if
testing does not meet our recommendations._
Mechanical compaction of the' slope, to, grade
during construction should utilize two types of
compactive effort-.. First, horizontal fi-ll lifts,
should be compac,t'ed during' fill placemen:t • This
equipment should--providecompact.iveeff.ort, to,
the outer edge-of the fill slope. Sloughing of
fill soils should, not be permitted-to drift down
the slope. Secondly, at'. ipt'e,rvals.-not exceeding
four feet in vertical slope height or-the
capability of available equi'pment', whichever -is
less, fill slop.es' should be backrolled with a
sheepsfoot-type" roller. Moisture condittons, of
the slope fill soils should be maintained
throughout the compaction process. Generally
upon slope compte,tion, the entire slope should
be compacted uti,lizing typical methods, (i. e.
sheepsfoot rolling, bulldozer tracking_, or
rolling with rubber-tired,heavy equipment).
Slope construction-grade sta-kingshould be
removed as soon as possible in t:he slope
compaction process., FinaL slope compaction _
should be performed without grade sakes on-the
s lope face.,
In order to monitor slope cons-truct.lon
procedures, moisture and density tests will be
taken at regular intervals. Failure to achieve
the desired results will likely result in a
recommendation by the Geot~chnical Consultant
to overexcavate the slope surfaces followed by
reconstruction of the slopes utilizing over-
filling and cutttng back. procedu~es or further
compactive effort' with the conventional
backrolling approach. Other recommendations
may also be provided which would be
commensurate with field condit.ions.
6.4.3 Where placement offill above a natural slope
or above a cut slope is proposed, the fill
slope configuration as presented in the
accompanying Standard Details should be
adopted.
6.4.4 For pad areas above fill slopes, positive
drainage should be established away fro~ the
top-of-slope, as designed by the project civil
engineer.
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6.5 OFF-SITE FILL
6.6
6.5.1 Off-site fill should be treated in the same
manner as recommended in the specifications for
s.ite preparation, excavation, drains,.
compaction, etc.
6.5.2 Qff-site canyon fill should be placed in
prepar.ation for future. addit·ional. fill, as
shown in the accompanying Standard Details ..
6.5.3 Off-site fill subdrains temporarily termin~ted
(up canyon) should be sur.veyed for future
relocation and connection.
TRENCH BACKFILL
6.6.1 Utility trench backfill should, unless other-
wise recommended, be compacted by mechanical
means. Unless otherwise recommended, the
degree of compac.tion should be a minimum of. 90
percent of maximum. density (ASTM .D1557).
6.6.2 Backfill of exterior and interior trenches.
extending below a 1:1 projection'from the outer
edge of foundations should be mechani.cally
compacted to a minimum of 90 percent of the
laboratory maximum density.
6.6.3 Within slab areas~ but outside th~ influence of
foundations, trenches up to one foot wide and
two feet deep may be backfilled with sand (S.E", > 30), and consolidated by jetting, flooding or
by mechanical means. If on-site materials are
utilized, they sho~ld be wheel-rolled, tamped
or otherwise compacted to a firm condition.
For minor interior trenches, density t.esting
may be deleted or spot testing may be elected
if deemed necessary, based on review of
backfill operations during construction.
6.6.4 If utility contractors indicate that it is
undesirable to use compaction equipment in
close proximity to a buried conduit, the
Contractor may elect the ut.ilization of light
weight mechaq.i.cal compaction equipment and/or
shading of the conduit with clean, g.ranular
material, (S.E • .> 30) which should be
thoroughly moistened in the trench, prior to
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7.
8.
initiating mechanical compaction procedures.
Other methods of utility trench compaction may
also be appropri"ate" upon review, of the
Geotechnic'al Consultant at the time of
construction.
6.6.5 In cases where clean granular materials are
proposed for use in lieu of native materials o·r
where 'floodingor j e.tting is proposed, the
procedures should, be considered subject to
review by the·Geotechni.cal Consultant.
6.6.6 Clean granular backfill and/or bedding are not
recommended in slope areas unless provisions
are made for a drainage syste~ to ~itigate the
potential build-up of seepage forces and
piping.
DRAINAGE
7.1 Canyon subdrain systems recommended by the
Geotechnical Consultant should be installed in
accordance with the Standard Details. '
7.2 Typical subdrains for compacted fill buttresses, slope
stabilizations or sidehill masses, should be installed
in accordance with the specifications of the
'accompanying Standard Details.
7.3 Roof, pad and slope drainage should be directed away
from slopes and areas of structures to disposal Cl.'reas
via. suitable devices designed by the project civil
engineer (i.e., gutters, downspouts, concrete swales,
area drains, earth swales, etc.).
7.4 Drainage patterns established at the time of fine
grading should be maintained throughout the life of
the project. Property owne'rs should be made aware
that altering drainage patterns can be de.trimental to
slope stability and foundation performance.
SLOPE MAINTENANCE
8.1 LANDSCAPE PLANTS
In order to decrease erosion surficial slope stability
problems, slope planting should be accomplished at the
completion of grading. Slope planting should consist
of deep-rooting vegetation requiring little wate'l;"ing.
A Landscape Architect would be the test party to,
consult regarding actual types 6f plant$ and planting
configuration.
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Standard Guidelines
for Grading Projects
Page 16
8.2 IRRIGATION
8.2.1 Slope irrigation should be minimized. If
automatic timing devices are utilized on
irrigation systems, provisions should be made.
for interrupting normal irrigation during
periods of rainfall. .
8.2.2. Property owners should. be made aware. that
overwatering of slopes is detrimental to slope
stability and may contribute to slope seepage,
erosion and siltation problems in the
subdivision.
Rev 5188
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4-DIAMETER PERFORATED
PIPE BACK DRAIN
4-DIAME1';R"NON-PERFORATED
PIPE LATERAL DRAIN-
1 "
8LOPE' PER PLAN
H/2
,PROVIDE BACK DRAIN PER,'BACKDR,AIN
DETAIL. AN ADDITIONAL, BACKDRAIN '
AT'MID-SLOPE WILL BE:REQUIRED'FOR"
8LOPE IN EXCE88OF 40 FEET' HIGH.
KEY-DIMEN810NPER 80lL8 ENGINEER
(GENERALLY 1/2 8LOPEHEIG,HT. 15'
MINIMUM)
TYPICAL STABILIZATI:O'N FILL, D'E'TAIL,
DATE:
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4-DIAMEcTER-PERFORATED
PIPE BACK DRAIN
4-DIAMETER'-NON-PERFORATED
PIPE LATER'A"~DRA'IN,-,
SLOPE-PER· PLA·N
1
HI-2
PROV·IDE~BACKDR·A.IN-PER· BACKDRAIN· -
DETAIL~ ANADPITIONAL BACKDRAIN'
AT MID-SLOPE: WILL. BEc-REQUIRED FOR-
SLOPE IN EXCESS-OF 40 FEET. HIGH.
KEY-DIMENSI"ON· PJ:RSOILS ENGINEER-
I TYPICAL BUTTR:E.SS. FILL~ DETAIL
JOB N~~:., ~ ~ ~..-,,: ~f~():&~OImc-DATE:
I ..
-'_ I '-k':"~':",~~~ -
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NATURAL GROUND
PROVIDE--BACK DRAIN ,PER
BACKDRAIN DETAIL. AN '
AQDITIONAL BACKDRAIN
AT MID-SLOPE-WILL BE
'REQUIRED-FOR BACK
'SLOPES IN EXCESS OF
40 FEET HIGH. LOCA-
TIONS OF B,ACKDRAINS
AND OUTLETS PER SOILS
ENGINE~R: AND/OR 'EN--
GINEERING GEOLOGIST
PURING GRADING.
COMPACTED FILL
PROPOSED GRADING
BASE WIDTH ·W· DETERMINED
BY SOILS ENGINEER
TYPld-AL SHE-AR' KEY DETAIL-
DATE:-
.,' ... , "
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FIN'AL LIMIT OF
EXCAVATION
OVERBURDEN
(CREEP-PRONE)
DAYLIGHT
LINE
OV,EREXCAVATE
OVEREXCAVATE'
3· AND REPLACE7
WITH ,CO,..PACTED
FILL
--, -SOUND BEDROCK'
TYPICAL BENCHING
--------
PROVIDE BACK DRAIN PER BACKDRAIN
DETAIL. LOCATION OF BACK DRAIN AND
OUTLETS PER ,SOILS !=NGINEER ,AND/OR
ENGINEERING GEOLOGIST DURING
GRADING
EQUIPMENT' WIDTH (MINIMUM 1-5')
DAYLIGHT SHEAR Key DETAIL
JOB""NO,.:: ' , , . , " ,O·5;-.&79~~O,,:t''t-' '
DATE:' FIGURE:
4
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------------
BENCHING FILL, OVER NATURAL
SURFACE, OF FIRM
EARTH MATERIAL
BENCHING FILL, OVER CUT'
FINISH FILL SLOPE
.k.----
SURFACE OF FIRM
EARTH MATERIAL
10'
TYPICAL
15' MIN. OR STABILITY EQUIVALENT PER SOIL
ENGINEERING (INCLINED 2" MIN. INTOSLOPEl
BENCHING FOR COMP'ACTED. FILL DETAIL
FIGURE: .
. 5,
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FINISH SURFACE SLOPE
·3 FT3 MINIMUM PER LINE'AL FOOT
APPROVED' ,FILTER ROCK*
GRADIENT
COMPACTED FILL
<4-MINIMUM·APPROYE'D
PERF,ORATED PIPE;**
(PERFORATIONSOOWNl
MINIMUM· 2" GRADIENT",
TO OUTLET'
BENCH INCLINED TOWARD,
QRAIN'
<4-MINIMUM DIAMETER'
SOLIDOUTLET~ PIPE·
SPACED"::PER"'SOIL
ENGINEER'REQUIRE-'"
MEN", DURING GRADING, -TYPICAL-BENCHING
12-MINIMUM COVER
DETAIL A-A,
COMPACTED
BACKFILL
1.-.....;::=:;..._-' •.
II----~-.,......, ---fl·
TEMPORARY FILL LEVEL
<4'-MINIMUM DIAMETER
APPROVED SOLID
OUTLET PIPE
12-MINIMUM--' *FILTER ROCK TO MEET FO,-LOWING
SP.ECIFICATIONS OR APPROVED EOUAL:
SIEVe' PERCENTAGE PAS.SIN<i
IAPPROVED PIPE TYPE: 1-
3/<4-
3/8-
NO.<4
100
90-tOO
<40-100
25-<40
SCHEDULE <40 POLYVINYL CHLORIDE
(P.V.C.> OR APPROVED EQUAL. I MINIMUM CRUSH STRENGTH 1000 PSI. NO.30
NO.50
HO.200
TYPICAL BAC.KORAIN 'O·ETAIL.
DATE:
5~15
0-7
0-3
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FINISH~ SURFACE SLOPE
MINIMUM.-SFTS PER· LINEAL FOOT
OPEN GRADED AGGREGATE*
T APE AND SE~L ·AT· CONT"ACT
COMPACTED FILL
GRADIE'NT
·SUPAC '8-PFABRIC OR
APPROVED eQUAL.
A '4" MINIMUM-APPROVED
4" MINIMUM··DIAMETER
SOLID OUTLET PIPE
SPACED PER' SOIL
ENGINEER-REQUIREMENTS
--t--........ -
PERFORATED PIPE
(PERFORATIONS, DOWN)
MINIMUM. 2., GRADIENT
TO OUTLET .'
MINIMUM
12" COVER
J-
TYPICAL
BENCHING.
.DETAIL A-A
EJENCH INCLINED
TOWARPDRAIN
·TEMPORARY FILL LEVEL
COMPACTED
BACKFILL MINIMUM 4" DIAMETER APPROVED
SOLID OUTLET PIPE
~12"---1 1 MINIMUM.'I
* NOTE: AGGREGATE TO MEET FOLLOWING
SPECIFICATIONS OR APPROVED EQ'UAL:
SIEVE SIZE
1 1/2"
1"
S/4"
S/8"
NO. 200·
PERCENTAGE PASSING'
100
5-40.
0-17
0-7 o-s
BACKDR.AIN DETAIL (GEOFABR;IC)
DATE: juLy" 19:8:8:~ .
FIGURE:
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--_.....-..-...._----.'-f
SURF-"CE OF
FIRM EARTH.
MATERIAL
" /. --" ~/ <'\ COMPACTED FILL /// .
TVPICAL BENCHING \\ /./
\\, //
L..--4.. .;--_~ / A-...Jo-I
REMOVE UNSUITABLE
MATERIAL
SEE DETAIL BELOW
DETAIL
INCL.INE TOWARD DRAIN
MINIMUM 4-DIAMETER APPROVED
PERF·ORATED PIPE (PERFORATIONS
bOWN)
MINIMUM 8 FT3 PER LINEAR FOOT
OF APPROVED FILTER MATERIAL I..------.J:G-FILTER MATERIAL BEDDING'
L 14-I, 1 MINIMUM 1
FILTER MATERIAL TO MEET FOLLOWING
$PECIFICATION OR APPROVED EQUAL:
SIEVE SIZE PERCENTAGE
1· 100
3'/4-80-100
3/S-40-100
NO.4 25-40
NO.30 5-15
NO.50 0-7
NO.200 0-3
APPROVED PIPE TO BE SCHEDULE 40
POLY-VINYL-CHLORIDE (P.V.C.> OR
AP·PROVEDEQUAL. MINIMUM CRUSH .
STRENGTH 1000 pal
PIPE_ DIAMETER. TO MEET THE
FOLLOWING CRITERIA, SUBJEqT TO
FIELD REVIEW BASED ON ACTUAL
GEOTECHNICAL CONDITIONS
ENCOUNTERED DURING GRADING
LENG1H OF RUN
UPPER 500'
NEXT 1000'
:> 150Q'
PIj)E D_IAMETER
TYPICAL' CANYON SUBDRAIN DETAIL
FIGURE:
JULY 1988-1, 8
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CANYON SUaO·R'AINo OE,TAILS--
-----J . SURf.ACE: OF
FIRM 'EARTH
................ " // , , //
,,\ COMPAC-TED· FILL / /
\ /.
\\ .1/ " // TYPICAL. BENCHING _ "./ REMOVE UNSUITABLE. ~~. _/ MATERI'AL ~ ~
I·NCLIN E::'TO W-AR D-' D RA I N
SEE DETAILS
TRENCH DET'AIL.
OPTIQNAL V-DITCH DETAIL
8UPAC ·S"'P FABRIC
O'R'-APPROVED EQUAL
,MINIMUM: 9 Ft3 . PER· LINEAL
FOOT O·F· APPROVED DRAIN .
MATE·RIA·L
8UPAC:--:5-P' FABRI-C~OR'
APPROVED ~QU'AL"
MINIMUM 9 FT3 PER LINEAL FOOT
OF APPROVED DRAIN MAl'ERIAL
ORAIN MATERIAL TO MEET FOLLOWING
SPECIF'ICATION OR APPROVED EQUAL:.
81 E'V ES t ZoE
1 1/2-
1-
3/4-
3/S-
NO.200
PERCENTAGE PASSING
.SS-100
5-40
0-17
0-7
0-3
ADD MINIMUM· 4-DIA:METER
APPROVED PERf.ORATED
PIPE WHEN GRADIE,NT 18
LESS THAN 2 ..
APPROVED PIPE TO' BE
8C.HEDULE 40 POLY-VINYL-
CHLORIDE (P.V.C.) OR·
APPROVED EQUA·L. MINIMUM
CRU8H 8·TRENGTH 1000 p .• i.
GEOFABRIC SU'BORAIN'
DATE: FIGUR:E:
9
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_ ......
OF FINAL EXCAVAnON
:rOE Of8LOPE: 8HOWN·,
ON GRADING",PLAN
TYPICAL. BENCH
HEIGHT,
PROVIDE B'ACKDR'AIN A8
REQUIR'ED PERRECOM-'
MENDATtON8 OF80lL8
ENGINEER DURING GRADING
WHERE NATURAL SLOPE GRADIENT 18 5: 1 OR LES8.
BENCHING ,IS NOT NECESSARY. HOWEVER~ FILL IS
NOT TO BE PLACED O~ COMP~ESSIBLE OR UNSUIT-
ABL.E MATERIAL.
FILL SLOPE ABOVE,~NATURAL GR,O'UND DETAIL
DATE: FIGURE:,
, , '
7' -,,, .... ::. ~ i,
1 '_~' ::. J .-_:-
10
-------------------
REMOVE ALL TQPSOIL. COLLUVIUM
AND CREEP MATERIAL FROM
TRANSITION "
CUT/FILL CONTACT SHOWN
ON GRADI'NG PLAN
CUT /FILL CONTACT SHOWN
ON -AS-BUILT-
NATURAl:~ .._ ...... TOPOGRAPHY ...... ..__ ...... --. -....... --. ---. ...-"-CUT SLOPE*
..--
",," F ILL ",,"" ..,. ..,." . ",,"" N1S. ...,..-.;;.~ __ --, "" . f.~O " .. , ,,"" , ... ~ ..-"-
" ...... ...... G ~ 1S.1S. "" .......
" ....... 1 ~"O "" ...... , .. "', ...... ...... U" v .. _ .
."...".. ...... GO\..\....;,..; ....... ."..
",,~·\&O,\..·~~..-~----------~i ~.".. "(0,, ............ ............ _ . ............ .".. .
BEDROCK OR· APPROVED
FOUNPATIO,. MATERIAL.
* NOTE: CUT SLOPE PORT.IO" SHALL BE MADE
PRIOfi TO 'PLACEME"T OF FILL
FILL SLOPE ABOVE ·CUT SLOPE DETAIL
JOB NO •. : 05-4879-011-00-00 PATE:
> ,; ,
. FI·GURE: JULY 1988 11
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GENEBAL GRADING RE'COMMENDATIONS
CUT LOT
-...,..~~ --' ----------~----------~ --, TOPSOIL"C'OLtUVIUMAND, ~~~
WEATHERED BEDROCK. _~ , -----' ~
----
_----ORIGINAL
. GROUND,
~~
~
,,,,~
-~ ~-
--UNWEATHERED BEDROCK
OVEREXCAVATE AND
REGRADE
CUT/FILL LOT (TRANSITION)
-----,~ ---~ --..-"-' ----",..... TOPSOIL. ..-"-..... COLLUVIUM AND ..-..:0.. ___ _
WEATHERED ..-"-
BEDROCK .;
COMPACTED FILL
UNWEATHERED BEDROCK
..-..-"-",.
TRANSITION LOT DETAIL
DATE:
3'
OVEREXCAVAT.EAN,D
REGRADE,
FIGURE: " '12
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BUI.LDING
FINISHED GRADE
, CLEAR AREA FOR
FOUNDATION. UTILITIES.,
AND SWIMMING POOLS
o
0'f q
__ '....,;~4_' '., l'
-~INDROW'
o
SLOPE FACE
STREET'
5' OR· BELOW~ DEPTH OF
DEEPEST" UTILITY TRE'NCH
(WHICHEVER GREATER')
TYPICAL WINDROW DE.TAIL(ED'GE:'VIE.W)' "
GR'A'Nui.AR SOIL FL.OOD'ED)·' -
TO FILL VOIDS
HORIZONTALLY PLACE'D
QOMPA9TION FILL
PROFIL.E VIEW
,ROCK DIS'PO,SAL DETAI'L
JOB-NO.'; . FIGURE: 13
II 11
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11