HomeMy WebLinkAbout; Laguna Riviera 29 Acres; Soils Report; 1981-05-04-
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PRELIMINARY SOIL AND GEOLOGICAL INVESTIGATION FOR THE PROPOSED LAGUNA RIVIERA - 29 ACRES CARLSBAD, CALIFORNIA
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Prepared For
Kamar Construction Co., Inc. 325 Elm Avenue Carlsbad, California 92008
ENGINEERING DEPT. LIBRARY
City of Carlsbad
2075 Las Pa!mas !irive
carlsbaq CA 92GtKHE59
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3467 K”rtZ street San Diego. California 92110
714-224-2911 Telex 697-841
WoodwardGlyde Cons&ants
May 4, 1981 Project No. SllOlW-SIOI
Kamar Construction Co., Inc. 325 Elm Avenue Carlsbad, California 92008
Attention: Mr. Jerry Rombotis
PRELIMINARY SOIL AND GEOLOGICAL INVESTIGATION FOR TBE PROPOSED LAGUNA RIVIERA - 29 ACRES CARLSBAD, CALIFORNIA
Gentlemen:
We are pleased to provide the accompanying report, which pre- sents the results of our geotechnical investigation for the subject project. The report presents our conclusions and rec- ommendations pertaining to the site, as well as the results of our field explorations.
If you have any questions, or if we can be of further service, please give us a call.
Very truly yours,
WOODWARD-CLYDE CONSULTANTS
Robert J. Dowlen C.E.G. 1011
RFJ/RPW/MP,R/JB/nun Attachments
(5)
Consulting Engineers. Geologists and Environmental Scientists
Ofiices in Other Princioal Cities
Richard P. While R.E. 21992
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Reference No. 51101W-SIOl WoodwardGyde Consultants
TABLE OF CONTENTS
PURPOSE OF INVESTIGATION
BACKGRUND INFORMATION AND PROJECT DESCRIPTION
Field and Laboratory Investigations
SITE, SOIL, AND GEOLOGIC CONDITIONS
Geologic Settinq Topography and Site Conditions Subsurface Conditions
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Fill Soils (Qf) Topsoil (unmapped) Terrace Deposits (Qt) Santiago Formation (Tsa)
Structure 6 Landslides 6 Ground Water 6
DISCUSSIONS, CONCLUSIONS, AND RECOMMENDATIONS 6
Potential Geologic Hazards 6
Faulting and Ground Breakage 6 Liquefaction 7 Landslides 7
Ground Water 7 General Soil Conditions 8 Slope Stability 8 Gradinq 10 Foundations 11
RISK AND OTHER CONSIDERATIONS
FIGURE 1 - SITE PLAN
APPENDIX A - FIELD INVESTIGATION
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Woodward-Clyde Consultants
TABLE OF CONTENTS (Continued)
Page
FIGURE A-l - KEY TO LOGS
FIGURES A-2 THROUGH A-5 - LOGS OF TEST BORINGS
FIGURES A-6 THROUGH A-8 - LOGS OF TEST PITS
FIGURE A-9 - LOG OF CUT SLOPE
APPENDIX B - LABORATORY TESTS B-l
FIGURES B-l THROUGH B-2 - GRAIN SIZE DISTRIBUTION CURVES
FIGURE B-3 - FILL SUITABILITY TESTS
APPENDIX C - BORING 1 TAKEN FROM SOIL AND GEOLOGICAL INVESTIGATION FOR THE PROPOSED LAGUNA RIVIERA, UNIT 11, DATED FEBRUARY 23, 1981
APPENDIX D - SLOPE STABILITY D-l
APPENDIX E - SPECIFICATIONS FOR CONTROLLED FILL E-l
APPENDIX F - GUIDE SPECIFICATIONS FOR SUBSURFACE DRAINS F-l
APPENDIX G - OVERSIZE ROCK PLACEMENT AREAS G-l
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Reference No. 511OlW-SIOl Woodward-Clyde Consultants
PRELIMINARY SOIL AND GEOLOGICAL INVESTIGATION
FOR TBE PROPOSED
LAGUNA RIVIERA - 29 ACRES
CARLSBAD, CALIFORNIA
This report presents the results of our preliminary
soil and geological investigation at the site of the proposed
Laguna Riviera - 29 Acres, residential subdivision. The site
is located northwest of the intersection of Park Drive and
Valencia Avenue, in the Ranch0 Agua Hedionda section of
Carlsbad, California. Laguna Riviera Units 10 and 11 border
the property to the east and northeast.
PURPOSE OF INVESTIGATION
The purpose of our investigation is to assist Kamar
Construction Company, Inc., and their consultants in evalu-
ating the property and in project design. This report pre-
sents our conclusions and/or recommendations regarding:
0 Geologic setting of the site,
0 Potential geologic hazards,
0 General subsurface soil conditions,
0 General extent and condition of existing fill soils,
0 Condition of areas to receive fill,
0 Presence and effect of expansive soils,
0 Depth to water (if within the depth of our sub- surface investigation),
0 Types and depths of foundations and allowable soil bearing pressures.
Reference No. SllOlW-SIOl Woodward-Clyde Consultants
BACKGROUND INFORMATION AND PROJECT DESCRIPTION
To aid in our study, we have discussed the project
with Mr. Jerry Rombotis, and have been provided with an un-
dated, "Tentative Map of Laguna Riviera, CT 80" (scale:
1" = 40'), prepared by Rick Engineering Company (Fig. 1). In
addition, we have reviewed applicable geologic and geotech-
nical data from adjacent areas, including:
0 "Soil and Geological Investigation for the Proposed Laguna Riviera, Unit 11, Carlsbad, California, pre- pared by our firm (February 23, 1981).
0 "Laguna Riviera Unit 10, CT-80 Carlsbad, California, Testing and Observation Services During Grading Operations; Final Report of Work from September 16 through October 10, 1980, prepared by Geocon, Inc.. (October 17, 1980)
0 "Soil Investigation for Laguna Riviera, Carlsbad, California," prepared by Geocon, Inc. (April 7, 1980).
0 "Laguna Riviera Unit 5, Offsite Fill Areas A and B, Carlsbad! California," prepared by Woodward- Gizienski &Associates (April 5, 1972).
0 "Faulting in the Oceanside, Carlsbad, and Vista Areas, Northern San Diego County, California," by :olwY of scamp Dennis Hannan, in Studies on the Ge Pendleton, and Western San Diego County, California, published by the San Diego Association of Geologist (1975).
0 "Geologic Map of a Portion of the San Luis Rey Quad- rangle, San Diego County, California,' M.S. thesis by Kenneth L. Wilson, University of California, Riverside (1972).
We understand that the proposed project will involve
grading the eastern approximate three-quarters of the 29-acre
PUD parcel into level pads for construction of approximately
122 living units. We understand that the proposed construc-
tion will be limited to one- and/or two-story, woodframe and
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stucco multi-family residential structures, supported on con-
tinuous footings and having concrete slab-on-grade floors. We
also understand that proposed cut and fill slopes will have
inclinations of 2 to 1 (horizontal to vertical) or flatter,
and will be a maximum of 30 feet high. Along the eastern
property line, fill slopes of up to 30 feet high (3 to 1
inclination) and cut slopes with maximum heights of 15 feet (2
to 1 inclination) are proposed. These slopes will be an
extension of existing cut and fill slopes which taper into
Units 10 and 11. The existing slopes have 2 to 1 inclinations
and are a maximum of 20 feet in height.
Field and Laboratory Investigations
Our field investigation included making a visual
geologic reconnaissance of existing surface conditions, making
four bucket auger boring and five backhoe test pits, and
obtaining representative soil samples. The borings and test
pits were advanced to depths of up to 34 feet and 10-l/2 feet,
respectively. In addition, a log was prepared of an existing
cut slope along Park Drive. The locations of these test
explorations are shown on Fig. 1.
A Key to Logs is presented in Appendix A as
Fig. A-l. Simplified logs of the borings and test pits are
presented in Appendix A as Figs. A-2 through A-8 . The cut
slope log is shown on Fig. A-9. The descriptions on the logs
are based on field logs and sample inspection. Results of the
laboratory tests are shown at the corresponding sample loca-
tions on the logs and in Appendix B. The field investigation
and laboratory testing programs are discussed in Appendixes A
and B, respectively. A copy of Boring 1 made during the
investigation for the adjacent Unit 11, is shown.
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SITE, SOIL, AND GEOLOGIC CONDITIONS
Geologic Setting
The site lies within an area characterised by
Pleistocene age beach and lagoonal deposits overlying Tertiary
age sediments of the coastal foothills.
Topography and Site Conditions
The site covers major portions of a broad south-
trending ridge and the neigbboring southern flanks of a higher
mesa surface. Elevations range from over 120 feet (MSLD) in
the northern corner of the site to less than 14 feet along
Park Drive in the central areas of the property (Fig. 1).
Natural slope inclinations vary from a maximum of
approximately 2 to 1 on the ridge flanks, to nearly flat on
sections of the ridge top. Vegetation varies from a sparse
growth of grasses in the southern regions to moderate to dense
brush along the drainages and western sections. Compacted
fill soils, placed in conjunction with the grading of Units 10
and 11, are present in drainages along the eastern site bound-
ary. End-dumped fill and piles of loose topsoils and brush
are also found in this general area. Existing cut and fill
slopes, inclined at approximately l-1/2 to 1, are present
along Park Drive and the eastern boundary.
We understand that two water lines cross the north-
ern most corner of the property with one line paralleling the
northwest boundary line. Sewer and electrical utilities are
present along Park Drive.
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Subsurface Conditions
The site is underlain by compacted fill soils, top-
soil, Pleistocene age terrace deposits and the Eocene age
Santiago Formation. These units are described below; their
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area1 extents, with the exception of the topsoil, are approx-
imately shown on Fig. 1. The geologic map symbol for each
unit is given after the formal name for the unit.
Fill Soils (Qf) - Undocumented fill soils, estimated
to be up to approximately 8 feet in thickness, are present in
drainage swales along the eastern boundary. These soils,
visually classified as silty sands, appear to represent a
regrading of existing natural drainage swales.
Topsoil (unmapped) - A topsoil layer, composed of
compressible silty sand grading to sandy clay, is present on
the natural hillsides and beneath the loose fill soils in Test
Pit 3. It is estimated that these soils range from 1 to
3 feetin thickness.
Terrace Deposits (Qt) - The eastern two-thirds of
the site is underlain by terrace deposits composed of dense
silty to clayey sands containing randomly dispersed interbeds
and lenses of sandy to silty clay. The sandy portions were
found to range from lightly cemented to cohesionless and non-
expansive to moderately expansive. The clay layers are gener-
ally highly expansive. These materials were found to be in
excess of 25 to 30 feetin thickness in the test borings.
Santiago Formation (Tsa) - The entire site is under-
lain by moderately well indurated, very fine to coarse silty
to clayey sands of the Santiago Formation. Interbeds and
clasts of sandy to silty clay are present within the sand with
varying regularity and thickness. Cemented zones are locally
present in this unit and may cause oversize materials to be
generated during grading. We expect that the granular portion
of the unit ranges from nonexpansive to moderately expansive;
the claystone lenses are highly expansive.
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- Structure and Faultinq
Our field investigation indicated that bedding
within the Santiago Formation and terrace deposits is inclined
in a southerly direction at approximately 10 degrees, and
between 4 and 7 degrees, respectively. This orientation rep-
resents a potentially adverse condition for all south-facing
cut slopes.
No faults or indications of faults were observed
during our reconnaissance, and no faults are mapped on the
site.
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Landslides
Our studies did not reveal the presence of land-
slides on the site.
Ground Water
No ground water seeps, springs, or abnormally wet
areas were observed during our visual reconnaissance or in the
test excavations.
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DISCUSSIONS, CONCLUSIONS, AND RECOMMENDATIONS
The discussions, conclusions, and recommendations
presented in this report are based on the results of our field
and laboratory studies, previous work in the area, analyses,
and professional judgment.
Potential Geologic Hazards
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Faulting and Ground Breakage - Our reconnaissance,
literature review, and subsurface explorations did not reveal
the presence of any faulting on the site.
The nearest known active fault along which seismic
events of magnitude 4 or greater have occurred is in the
Elsinore Fault zone, mapped some 22 miles to the northeast.
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The closest significant faulting is the northern
extension of the Rose Canyon Fault zone, which is mapped off-
shore approximately 9 miles to the southwest. No magnitude 4
or larger earthquakes have been recorded on the Rose Canyon
Fault zone.
Liquefaction - The formational soils on the site are
dense to very dense, and there is no apparent permanent ground
water table within expected grading limits. In our opinion,
the formational soils do not have a potential for
liquefaction. The topsoils have a potential for liquefaction
in a saturated state. In our opinion, this potential can be
essentially eliminated by over-excavation and recompaction as
recommended under "Grading."
Landslides - Our review and field investigations did
not reveal the presence of any landslides on the site.
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Ground Water
Our field investigation did not reveal any ground
water seeps, springs, or abnormally wet areas and we do not
expect that a shallow permanent ground water table is present
within the proposed grading limits.
We recommend that positive measures be taken to
properly finish grade each lot after the residential struc-
tures and other improvements are in place, so that drainage
waters from the lots and adjacent properties are directed off
the lots and away from house foundations, floor slabs, and
slopes. Even with these provisions, experience in adjacent
areas has shown that a shallow ground water or surface water
condition can and may develop in areas where no such water
condition existed prior to site development; this is partic-
ularly true in years of heavy rainfall and in residential sub-
divisions where a substantial increase in surface water
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infiltration results from landscape irrigation. Examination
of the subdivision during grading will help evaluate areas
that could present future seepage problems in cut slopes.
General Soil Conditions
The materials expected to be used in structural
fills and in constructed slopes are primarily silty to clayey
sands containing sandy and silty clay interbeds.
In our opinion, the soils on k-l e site can generally
be excavated to design depths by light to moderate effort by
heavy-duty excavation equipment. Excavation of localised
cemented zones in the Santiago Formation may require heavier
ripping, and may result in the generation of oversize
material.
Soils suitable for use at finish grade are present
in the formations underlying the site; however, clayey strata
have been identified in the excavations. The clay portions of
the formational soils and surficial soils are highly expansive
and unsuitable for use at finish grade. Selective grading may
be required including stockpiling of finish grade soils in
order to arrive at satisfactory finish grade conditions.
Slope Stability
We have performed stability analyses for the pro-
posed slopes by the Janbu method using the following
parameters:
Parameter
Undisturbed
materials
C’ -
300 psf
1
125 pcf
Compacted Fill 25' 300 psf 125 pcf
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Our selection of soil parameters for analysis is
based on the results of laboratory tests performed on samples
during our field explorations and from studies on similar
formational soils in the Carlsbad area.
The results of those analyses indicate that the
proposed 2 to 1 inclined fill and cut slopes, if free of
claystone interbeds, have calculated factors of safety against
deep-seated slope failure in excess of 1.5 for static condi-
tions. Slope stability calculations are attached (Appen-
dix D). South-facing slopes made in the terrace deposits may
expose weak, southerly dipping, clay seams. It is our profes-
sional judgment that cut slopes in excess of 10 feet in height
with exposed weak clay seams have a moderate potential for
slope instability if constructed as indicated.
We recommend buttressing south-facing cut slopes
with exposed weak clay seams that are in excess of 10 feet in
height in accordance with the following sketch (see page 9A).
This treatment may necessitate the slopes being overbuilt
3 feet and cutback to the finished grade surface.
Stability analyses require using parameters selected
from a range of possible values. There is a finite possibil-
ity that slopes having calculated factors of safety, as indi-
cated, could become unstable. .In our opinion, the probability
of slopes becoming unstable is low, and it is our professional
judgment that the proposed slopes can be constructed.
We recommend that an engineering geologist from our
firm inspect all cut slopes during grading to verify actual
geologic conditions and to provide design modifications, if
needed.
It should be noted that friable, cohesionless sands
were encountered in our test borings and may be exposed in the
cut slope faces when grading is completed. These materials
are extremely susceptible to erosion and may require special
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Slope may be overbuilt and cut back -,/
Finish
- Note 2 1 \Gravel Chimney Note 3
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SKETCH DETAIL AT MAXIMUM SECTION (NO SCALE)
NOTES:
(1)
(2)
(3)
(4)
Collector Collector Drain Drain
CHIMNEY DRAIN DETAIL (NO SCALE)
Safe construction slopes to be determined by the contractor.
6-inch diameter perforated thick walled PVC or ABS pipe. Outlet from buttress should be nonperforated and should slope to drain at convenient outlet. Outlet end shall be protected against damage and readily accessible for observation and maintenance.
Class II permeable California State Specification
Section 68-1.025 or combined aggregate State Specification, Section 90-3.04 l-inch maximum, 6-inch minimum encasement of drain pipe.
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landscaping procedures to reduce the potential for slope
erosion due to irrigation and rainfall. Proper landscaping
procedures should be recommended by the project landscape
architect.
Grading
We recommend that all earthwork be done in accor-
dance with the attached Specifications for Controlled Fill
(Appendix E). Woodward-Clyde Consultants should observe the
grading and test compacted fills.
We recommend that a pre-construction conference be
held at the site with the developer, civil engineer, contrac-
tor, Andy geotechnical engineer in attendance. Special soil
handling and the grading plans can be discussed at that time.
We recommend that all trash, construction debris,
brush piles, and waste materials be removed from the site
before grading. We recommend that all porous topsoils and
fill ~soils not removed by planned grading be excavated or
scarified as required, watered, and then recompacted prior to
placing any additional fill. We recommend that the soil
engineer evaluate the actual depth and extent of excavation in
the field at the time of grading.
We recommend installing a subsurface drain beneath
fills placed in the Neblina Drive easement in accordance with
the attached Specifications for Subsurface Drains (Appen-
dix F). We recommend that the subsurface drain be extended
"upstream" in the drainage to the point where it is covered by
a minimum 10 feet of fill. The actual location of the sub-
drain will be evaluated and recommended when grading plans are
available.
We recommend that oversize materials (between 2 and
4 feet), if encountered, be placed in accordance with the
attached Oversize Rock Placement Areas (Appendix G). We
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recommend that rock fragments larger than 4 feet be hauled
from the site or broken into smaller pieces.
Highly expansive clayey soils could be encountered
at grade in areas of shallow cuts and fills (daylight areas),
or in deeper cuts. We recommend that these clayey soils be
excavated, where encountered, over the entire level lot area
to a minimum of 2 feet below finish grade, and then be re-
placed with properly compacted, nonexpansive soils or slightly
expansive soils available on the site. The more clayey soils
can be placed and properly compacted in the deeper fill areas.
We recommend that the upper 2 feet of materials in
the fill areas be composed of finish grade, granular soils.
Finish grade soils are defined as granular soils that have a
potential swell of less than 6 percent when recompacted to 90
percent of maximum laboratory density at optimum moisture
content, placed under an axial load of 160 psf, and soaked in
water.
We recommend slightly to moderately expansive soils,
that is soils swelling between 3 and 6 percent, be compacted
at moisture contents of 3 to 5 percent over optimum water
content when they are used within 2 feet of finish grade.
Foundations
We recommend that foundations for structures founded
in natural or properly compacted, nonexpansive to moderately
expansive soils be designed for an allowable soil bearing
pressure of 2,000 psf (dead plus live load). In our opinion,
this bearing pressure can be increased by up to one-third for
transient loads caused by wind or seismic forces. For these
bearing pressures, we recommend that all footings be founded a
minimum of 12 inches below compacted fill or undisturbed cut
lot grade, be a minimum of 12 inches wide, and be founded a
minimum horizontal distance of 8 feet from slope faces.
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We recommend that foundations founded in slightly to
moderately expansive materials be reinforced top and bottom
with at least one No. 4 steel bar, and that the concrete
slabs-on-grade be a minimum 4 inches thick and be underlain by
4 inches of coarse, clean sand and reinforced by 6 x 6, lO/lO
welded wire mesh. A plastic membrane should also be provided
under slabs.
RISK AND OTHER CONSIDERATIONS
We have observed only a small portion of the perti-
nent soil, and ground water conditions on the site. The
recommendations made herein are based on the assumption that
conditions do not deviate appreciably from those found during
our field investigation. If the plans for site development
change, or if variations or undesirable geotechnical condi-
tions are encountered during construction, the geotechnical
consultant should be consulted for further recommendations.
We recommend that the geotechnical consultant review
all grading and foundation plans before finalizing to verify
that the intent of the recommendations presented herein have
been properly interpreted and incorporated into the contract
documents. We further recommend that the geotechnical con-
sultant observe the site grading, and subgrade preparation
under concrete slabs and paved areas, and foundation
excavations.
It should be understood that California is an area
of high seismic risk. It is generally considered economically
unfeasible to build totally earthquake-resistant structures;
therefore, it is possible that a large or nearby earthquake
could cause damage at the site.
Professional judgments presented herein are based
partly on our evaluations of the technical information -
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gathered, partly on our understanding of the proposed con-
struction, and partly on our general experience in the geo-
technical field. Our engineering work and judgments rendered
meet current professional standards. We do not guarantee the
performance of the project in any respect.
This firm does not practice or consult in the field
of safety engineering. We do not direct the contractor's
operations, and we cannot be responsible for the safety of
other than our own personnel on the site; therefore, the
safety of others is the responsibility of the contractor. The
contractor should notify the owner if he considers any of the
recommended actions presented herein to be unsafe.
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APPENDIX A
FIELD INVESTIGATION
Four exploratory test borings and five test pits
were made at the approximate locations shown on Fig. 1. Our
field work was performed between February 2 and 5, 1981.
The test borings were made with a truck-mounted
30-inch diameter bucket auger and were down-hole logged. The
test pits were excavated by a John Deere Model 310-A backhoe.
Representative samples of the subsurface materials were
obtained from the test explorations and returned to our lab-
oratory for examination.
The locations of the test excavations and the ele-
vation of the ground surface at each location were estimated
from the plan prepared by Rick Engineering Company.
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Location
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Boring Number Elevation
I R -LE NUllSEll SOIL DESCRIPTION I r-
Very dense, damp, brown silty sand (SM)
WATER LEVEL -I
Af time Of drilling or as indicated. I L SOIL CLASSIFICATION I
soil Clsrrificationr are bared on the ““i&d soi, Clarrifiotlo” s+rtsm aid i”d”ck mlor, mature an* conrirtency. Field de%lip,lo”l haYe he” modified to reflect re.u,u Of laboratcf” analyser Mere apprOpri.t*.
DISTURBED SAMPLE LOCATION obtained b” collecting the auger C”,,i~S in a plmic or cloth b.
DRIVE SAMPLE LOCATION MODlFlED CALlFORNlA SAMPLER
SamPla With recorded tl,owr per ‘Dot was chained Wfh B Modi‘M California drive sampler lr’ ins!& diamem. 2.5” .Jurr,*e diamtrrl lined With sample t”t.s. The *m&r was driven ,“,.a ttm IOil at the bottom 0‘ the hole wtll a 140 &w”nd hammer falling 30 ,n*es.
DRY DENSITY Pounds pr Cubic Foot
MOISTURE CONTENT Rrcsnt Of my weight
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INDICATES SAMPLE TESTED FOR OTHER PROPERTIES GS - Grain size Dinriburion CT - Conrolidatmn Tell
LC - Laborator” G3moani.m “CS - “ncoon‘med comprerrion Test
Test
PI - Atferberg Limit* Test OS - Direct mea, Tel,
ST - Loaded Swell Test TX - Triaxial Com,mrrion Test
cc- Confined cnmprerrion
Ten
NOTE: In this column the rewlts of these tesis may be recorded
where applicable.
BLOW COUNT Number Of blowr readed to advance sampler one foot or II Indloted.
NOTESON FIELD INVESTIGATION
1. REFUSAL indiotes th* inability 10 extend excavation, practically. With aq”iwnmt being “Iad in tlw inve,tig.*ion.
- I KEY TO LOGS
LAGUNA RIVIERA 29 ACRES I
DRAWNW: ch O(ECKEDB": D,I ,ROJEclNO: SllOlW-SIOl DATE: 4-6-81 FlO”RENO: A-l
WOODWARO-CLYDE CONSULTANTS
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15 7
1 I
20 20 -
25 25
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(\- - - - --Grading to _ _ - - -
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Dense, damp, light gray brown, silty sand
TERRACE DEPOSITS
Grading to - - - - - -
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Very stiff, moist, dark brown, silty clay
(CH) TEFRACE DEPOSITS
Dense, damp, gray brown, silty sand (SM)
TERRACE DEPOSITS
I’ Bottom of Hdle I I
‘For d.scription 01 symbol,. we Figw. ‘For d.scription 01 symbol,. we Figw. A-l A-l
LOG OF TEST BORING 1 LOG OF TEST BORING 1
LAGUNA RIVIERA 29 ACRES LAGUNA RIVIERA 29 ACRES
DRAWNBY: ch DRAWNBY: ch 1 CHECKE.DBY:~~j ,ROJECTNO: 51101W-SIOl 1 DATE: 4-6-81 1 CHECKE.DBY:~~j ,ROJECTNO: 51101W-SIOl 1 DATE: 4-6-81 FIGURE wo: A-2 FIGURE wo: A-2
IN - FEET l MC ’
OTHEF rEsls
X,PI
Boring 1
Approximate El. 49' 1
SOIL DESCRIPTION
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Firm, moist, brown, silty clay (CH)
TOPSOIL AND SLOPEWASH
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Loose, damp, brown, clayey sand (SC)
TOPSOIL
Dense, moist, brown, silty sand (SM)
TERRACE DEPOSITS Bedding attitude N31E/4S
very coarse sand with pebbles; firable
Hard, damp, olive brown, silty to sandy
\ clay (CH) TERRACE DEPOSITS -----_- Grading to - - - - - -
Dense, damp, gray brown, clayey sand (SC)
to sandy clay (CL) TERRACE DEPOSITS
\-_ - -- - Grading to - - - - -
Dense, damp, pale brown, silty sand (SM)
TERRACE DEPOSITS
- Bedding attitude N3lW/5S at 22%'
Very stiff, moist, dark brown, silty clay
(CH) TERRACE DEPOSITS
L---- - Grading to - - - - -
\ Dense, moist, gray,brown, clayey sand (SC)
TERRACE DEPOSITS
-.
-.
-
-
-
-
-
-
roj -
00 -
-
Boring 2
Approximate El. 79'
>THER ‘ESTS T
S
S-AMPLE NUMBER I
SOIL DESCRIPTION
I Medium dense, moist, dark brown, silty sand
\ (SM) i porous TOPSOIL
Dense, damp, brown, clayey sand (SC)
\ TOPSOIL -- - -- Grading to - - - --
Dense, moist, reddish brown, silty sand
, (SM) TERRACE DEPOSITS
L--e- Grading to - - - - - -
Dense, moist, qray brown, clayey sand to
sandy clay (SC-CL)
TERRACE DEPOSITS . ---- Grading to- - _ _ _ Dense, moist, gray brown, silty sand (SM)
TERRACE DEPOSITS
- Bedding attitude N25W/4S at 13s'
/
Contact generally dipping to SW
Very stiff, moist, qray green, silty clay
\
(CH);some clay parting surfaces, many
carbonate zones TERRACE DEPOSITS
Dense, damp, light qray to dark brown,
Silty to clayey sand (SM-SC)
TERRACE DEPOSITS
Hard, damp, gray brown, sandy to silty
clay (CL) with shell fragments, many
clay parting surfaces
TERRACE DEPOSITS
Dense, damp, light brown to gray, sandy
silt (MH) some pockets of red brown sand
TERRACE DEPOSITS
Dense, damp, light qray brown, silty sand
\ (SM) TERRACE DEPOSITS
Bottom of Hole
*For description of symbols, SW Figure A-l
I I
LOG OF TEST BORING 2
LAGLINA RIVIERA 29 ACP.ES
DRAWNBY: ch 1 Cl,ECKEDBY:~$l PRWECTNO: 51101W-SIOl 1 DATE: 4-6-81 FIDURE ND! A-3
WnnrlWARn.EI VnF cnuwII TAYTS
-
5
10 -
15
-
20
25
30
-
r 01 -
‘DD -
)THEI rEsTs
S,PI
lS,LC
Boring 3
Approximate El. 94' I
SOIL DESCRIPTION
Loose, moist, dark brown, silty sand (SM);
\ porous TOPSOIL
\
Finn, damp, dark brown, sandy clay (CL)
TOPSOIL
Dense, moist, brown, clayey sand (SC)
TERRACE DEPOSITS
I- Lens of dark brown, silty clay (CH)
-) Lens of grayish brown, silty clay (CH)
Very stiff, moist, grayish brown, sandy
\ clay (CL) TERRACE DEPOSITS
Dense, moist, light qray brown, silty sand
, (SM) TERRACE DEPOSITS
\
Contact attitude approximately N75W/4S at
19'
Stiff, moist, dark olive, silty clay (CH)
TERRACE DEPOSITS
Dense, damp, light gray brown, silty sand
(34) TERRACE DEPOSITS
Bottom of Hole
‘For d.scription of wymbal,. SW Fi(plr,A-1 I 1
LOG OF TEST BORING 3
LAGUNA RIVIERA 29 ACRES
DRAWNBY: ch 1 C"ECKEDBY:@D] PROJECTNO: SllOlW-SIOl 1 DATE: 4-6-81 1 F‘OURE m):A-4
wnnIlwaD”.PI ““F rn”Clll TrlYTC
-
-
-
.-
-
-~
.-
;
-
DEPTH TES IN
FEET l MC
25- 25-
ITHE rEsTI
S,P
Boring 4
Approximate El. 119'
BAMPLE YUMBER SOIL DESCRIPTION
I Loose, damp, dark brown, silty sand (SM);
porous TOPSOIL
Dense, moist, red brown, silty sand (SM);
trace clay TERRACE DEPOSITS
----- Grading to - -, - - - -
Dense, -moi&, red brown to light olive
brown, clayey sand (X'to sandy clay (CL)
TERRACE DEPOSITS
c Approximate bedding N70E/4S at 29'
Very dense, damp, pale brown, clayey fine
sand (SC);cemented SANTIAGO FORMATION
Bottom of Hole
*For d.wi,xion 01 wnbol,. se. Figure ~-1
LOG OF TEST BORING 4
LAGUNA RIVIERA 29 ACP.ES
DRAWNBV: ch 1 CWECKEDW~1 PROJECTNO: 51101W-SIOl DATE: 4-6-81 1 FMWRE ~0: A-5
w”““wdnn.FI vns IYlYClll TaYTC
Test Pit 5
Approximate El. 72'
DEPTI c F:k
ITHEF ‘EETE 5AMPLE WMEER SOIL DESCRIPTION
Firm, moist, brown, sandy clay (CL)
\ TOPSOIL
Dense, damp, light brown, silty sand (SM)
\ TEP.RACE DEPOSITS
i‘
Hard, damp, dark olive, sandy clay (CL)
TERFJACE DEPOSITS
Contact attitude N20W/7S at 4#'
Dense, damp, pale brown, silty sand (SM);
friable TERRACE DEPOSITS \ Hard, moist, gray brown, silty to sandy
clay (CH) TERRACE DEPOSITS
i-l C
i-2 C
i-3 C
i-4 C
Bottom of Hole
15
-
Test Pit 6
- Approximate El. 78' 4 T
OTHEP TESTS I SAMPLE
I NUMOER SOIL DESCRIPTION
I
Loose, moist, dark brown, silty sand (SM);
\ PCZOUS TOPSOIL
J
16-l L'""
GS,LC
6-2
6-3
:(6-4 L
\ Hard,, damp, dark brown, sandy clay (CH)
_--- - Grading to - - - -
Very dense, damp, light gray, silty sand
(SW SANTIAGO FORMATION
Bottom of Hole
-
*For d.s.AFtim of .ymbolr. ,e. F&w. A-l
LOG OF TEST PITS 5 AND 6
LAGUNA RIVIERA 29 ACRES
DRAWNEY: ch 1 CHECKEDBY:~i, 1 PRDJECTN0: SllOlW-SIOl 1 DATE: 4-7-81 FlOUREIK):A-6
WOOOWARO-CLYDE CONSULTANTS
- rm - DD -
-
-
8c -
-
. T
-
ITHEI
‘ESTS -
S,PI
-
OTHE? TESTS
DEPTH 1
FL l MC
‘i 5
10 I
15 1
iT DI -
-00 -
-
Test Pit 7
Approximate El. 21'
1
SOIL DESCRIPTION
Loose, moist, dark brown, clayey sand (SC)
, TOPSOIL
\
Dense, damp, dark brown, clayey sand (SC)
TOPSOIL
Dense, damp, pale brown, silty sand (SM)
TERRACE DEPOSITS
- Bedding attitude N8W/4S at 9' \ Dense, damp, dark brown, clayey sand (SC)
i TERRACE DEPOSITS
Bottom of Hole
Test Pit 8
Approximate E1.35'
ERMPLE NUMBER SOIL DESCRIPTION
*For dmcrimion .a‘ wmbob. s.. ~imr. A-1
Loose, moist, dark gray brown, clayey sand
(SC) TOPSOIL
Dense, damp, dark gray brown, sandy clay
(CL) TOPSOIL
Hard, moist, brown, sandy clay (CL)
RESIDUAL SOIL
----- Grading to - _ - _ -
\
Very dense, damp, gray brown, clayey sand
(SC) SANTIAGO FORMATION
'Contact attitude N40W/12S at 6'
Very dense, damp, light gray, silty sand
(34 SANTIAGO FORMATION
Bottom of Hole
LOG OF TEST PITS 7 AND 8
LAGUNA RIVIERA 29 ACRES
DRAWNBY: ch 1 CHECKEDBY:RJD 1 PROJECTNO: 511OlW-SIOl 1 DATE: 4-7-81 FlGURE wo: A-7
.-
-
-.
-
1 DEPTHi TI DTHEI rsrs i*L(PLE IVMBEF
3-1
a-2 C
3-3 [
3-4 r
Test Pit 9
Approximate El. 21'
SOIL DESCRIPTION
Loose, moist, light brown, silty sand (SM);
\ TOPSOIL
Dense, damp, dark brown, clayey coarse sand
(SC) with shell fragments I TOPSOIL
L- - -- Grading to - - - - -
I Dense, moist, yellowish brown, clayey sand
\ (SC) TERRACE DEPOSITS
-_---_ Grading to ___ _ _ _
Dense, damp, dark brown, clayey sand to
I sandy clay (SC-CL) TERRACE DEPOSITS
---- - Grading to _ _
Dense, damp, brown, clayey sand (SC)
TERRACE DEPOSITS
Bottom of Hole
*Po,d.rription of ,ymbols,see Pigrn A-l
LOG OF TEST PIT 9
LAGUNA RIVIERA 29 ACRES.
DRAWIIIIY: ch 1 CHECKEDEX~9 [ ,N,.,ECTNO:5llOlW-SIOl 1 DATE: 4-7-81 1 FtOURE wo: A-8
WOOOWARO-CLYDE CONSULTANTS
-
-
-
-.
-
-
-
-
-
-
-
,~~
3THEI TESTS
-
cut slope 10
Approximate El. 62' ,
SOIL DESCRIPTION
\
Firm, dry, pale brown, sandy clay to
clayey sand (CL-SC) porous
I TOPSOIL
Firm, damp, light reddish brown, sandy clay Firm, damp, light reddish brown, sandy clay
(CL) (CL) TOPSOIL TOPSOIL
Hard, damp, light gray brown, fine sandy Hard, damp, light gray brown, fine sandy
clay (CL) clay (CL) TERRACE DEPOSITS TERRACE DEPOSITS
Hard, damp, olive to gray.to black, silty
clay (CH) TERRACE DEPOSITS
Dense, damp, pale brown, silty medium sand
(SM) TERRACE DEPOSITS
l"-3" lens of hard, damp, silty tray at 4+'
1"-2" l&s of hard, damp, balck to
brown, sandy clay (CL) at 5'r'
Hard, damp, olive brown, silty clay (CH)
TERRACE DEPOSITS
Contact attitude N38E/6S at 12'
Dense, damp, gray brown, clayey very fine
sand (SC) TERRACE DEPOSITS
\
Dense, damp, light gray, silty sand (SM)
TERRACE DEPOSITS
\ Beddinq attitude N69E/6S at 18%'
Hard, damp, olive gray, silty clay (CH)
\
TERRACE DEPOSITS
Contact attitude NlEW/7S at 214'
Dense. damp, gray brown, clayey very fine
sand (SC) TERRACE DEPOSITS
Dense, damp, light gray, silty sand (SC)
TERRACE DEPOSITS
Bottom of Hole
~~ordercription of rymbdr,us ~igwe A-l
1
LOG OF CU1 C SLOPE 10
lAGUNA RIVIE RA 29 ACRES
I DRAWNBY: ch 1 c"E‘ZKEDBY:~.\n 1 PRQlECTNO: SllOlW-SIOl DATE: 4-7-81 PIG”RE110: A-V
WOOOWARD.CLYIlE CONSULTANTS
Project No. 51101W-SIOl
APPENDIX B
LABORATORY TESTS
Woodward-Clyde Consultants
-
-
-
-
The materials observed in the test pits were
visually classified and evaluated with respect to strength,
swelling and compressibility characteristics; dry density; and
moisture content. The classifications were substantiated by
performing grain size analyses and evaluating plasticity
characteristics of representative samples of the soils. Fill
suitability tests, including compaction tests, expansibility
tests, and grain size analyses, were performed on samples of
the probable fill soils.
The grain size distribution curves are shown on Fig.
B-l. The results of fill suitability tests are reported on
Figs. B-2 and B-3.
-
B-l
-
-
COBBLES GRAVEL I SAND SILT and CLAY Coarse Fine Coarse Medi urn Fine
Mesh Opening - Ins Sieve Sizes Hydrometer Analysis I 1 i I
D
70
80
10.0 5.0 1.0 0. I 0.05 0.01 o.DD5 0.001
GRAIN SIZE IN HILLIHETERS
*LL - Liquid Limit
*PI - Plasticity Index
I GRAIN SIZE DISTRIBUTION CURVES
LAGUNA RIVIERA 29 ACRES I
DRAWN~V: ch 1 CHECKED sv:E>, PROJECT NO: 51101W-SIOl DATE:4-7-81 FlOURa wo: B-1
WOODWARD-CLYDE CONSULTANTS
-
-
-
-
I CoBGLES
GRAVEL I SAND
Cnarr* I SILT and CLAY ucrl i Fina I
Mesh Opening - Ins Sieve Sizes Hydrometer Analysis r I , I
loo 76 32 10 16203OW 0
90 IO
80 20
70 30
60 w:: f
2
50 “;
z
w 60:
30 70
20 60
IO so
0 100 loo 50 10.0 5.0 I.0 0.1 0.05 0.01 0.005 0.001
GRAIN SIZE IN HILLIHETERS
*LL - Liquid Limit
*PI - Plasticity Index
GRAIN SIZE DISTRIBUTION CURVES
LAGUNA RIVIERA 29 ACRES
DRAWN BY: ch CHECKEDBY: w PROJECTNO: SllOlW-SIOl DATE: J-7-81 FIGURE No: B-2
WOOOWARO-CLYDE CONSULTANTS
-
PLASTICITY CHARACTERISTICS 3-2 6-4
-
-
1E
Liquid Limit, %
Plasticity Index. %
Classification by Unified Soil
Classification Svstem
- -
SC SM I ~~~ -I--~~~~
’ ’
$ I I
,w 5 Kl )LJ 40
5
ZERO AIR VOIDSCURVES P 20
0 loo0 loo 10
IO
GRAIN SIZE. mm
MECHANICAL ANALYSIS
v DIRECT SHEAR TEST DATA 3-2
Dry Density, pcf 109
Initial Water Content. % 12
Final Water Content, % 20
Apparent Cohesion. psf 340
Apparent Friction Angle, degrees 16
SWELL TEST DATA
LABORATORY COMPACTION TEST
LABORATORY COMPACTION TESTMET,,OD:ASTM-D 1557-70 A
.-
FILL SUITABILITY TESTS
LAGUNA RIVIERA 29 ACRFS
DRAWN BY: ch 1 CnECKE~ q “: mu 1 PRwECT No: 51101w-s101 1 DATE: 4-7-81 PIOVRE NO+-’
Y,..m...Y.mm . . “IC -..“..a.. -*..-a
-
Project No. SllOlW-SIOl
-
-
-
WoodwardGlyde Consultants
APPENDIX C
Boring 1
Taken From
SOIL AND GEOLOGICAL INVESTIGATION
FOR THE PROPOSED
LAGUNA RIVIERA, UNIT II
Dated February 23, 1981
-
-
-
-
-
-
25:
-
30: _-
---
35-
-
-
40-
- r 01 - ‘DD -
-
>THEI rESTS
Boring 1
Approximate El. 53'
AMPLE
“MSER SOIL DESCRIPTION
Loose, damp, red-brown, clayey to silty
\ sand (SC-SM) TOPSOIL
Dense, moist, brown, silty to silty clayey,
medium sand (SM) with occasional red-brown
staining TERRACE DEPOSITS
Trace clayey gravels
Contact attitude N4% 15'N
Dense, moist, brown, silty coarse sand
(SM-SP); lightly cemented and cohesionless
TERRACE DEPOSITS
- Cross-bedding N25'E 22OS at 14'
- Clayey gravels
Dense, moist, brown, clayey sand (SC)
interbedded with stiff, moist, gray, sandy
to silty clay (CL-CH)
TERRACE DEPOSITS
Dense, moist, gray-brown, silty medium sand
(SW TERRACE DEPOSIIS
1 Becomes light gray-brown
Bottom of Hole
-For descriptio” 0‘ ,“mt.OlS. se pigun A-l
LOG OF TEST BORING 1
LAG"NA RIVERIA UNIT 11
DRAWNBY: ch 1 CHECKED SVk&p PROJECT NO: 51101w- SIol DATE:~-12-81 PlGURE NO: A-2 ,
C-l WOODWARD-CLYDE CONSULTANTS
-
-
-
Project No. SllOlW-SIOl
APPENDIX D
SLOPE STABILITY
Cut Slope
-
-
-
-
-s
-
Assumptions:
(1) Maximum height of slopes (2) Maximum slope inclination (3) Unit weight of soil (4) Apparent angle of internal friction (5) Apparent cohesion (6) No seepage forces
B= 30 2 to 1 Y = 125 pcf $ = 330 c = 300 psf
References:
(1) Janbu, N., "Stability Analysis of Slopes with Dimensionless Parameters, II Harvard Soil Mechanics Series No. 46, 1954.
(2) Janbu, N., "Dimensionless Parameters for Homogeneous Earth Slopes," JSMFD, NO. SM6, November 1967.
Analyses:
Safety Factor, F.S. = Ncf c Where 'Ncf is the stability YH number for slopes with both c and@.
A cf = YH tan $ = 8.1
C
From Fig. 10 of Reference (2) Ncf = 27
F.S. = 2.2
-
-.
-
D-l
-
-
-
Project No. 511OlW-SIOl
Slope Stability
Fill Slope
Assumptions:
,- (1) Maximum height of slopes (2) Maximum slope inclination (3) Unit weight of soil (4) Apparent angle of internal friction (5) Apparent cohesion (6) No seepage forces
H = 30' 2 to 1 Y = 125 pcf $' = 25'= c = 300 psf
- References:
(1)
(2)
Janbu, N., "Stability Analysis of Slopes with Dimensionless Parameters," Harvard Soil Mechanics Series No. 46, 1954.
Janbu, N., "Dimensionless Parameters for Homogeneous Earth Slopes," JSMFD, NO. SM6, November 1967.
Analyses:
Safety Factor, F.S. = Ncf C Where 'N cf is the stability
YH number for slopes with both c and$.
A cf = w tan 4 = 5.6
C
From Fig. 10 of Reference (2) Ncf = 22
F.S. = 1.8
D-2
-
. *
APPENDIX E
SPECIFICATIONS FOR CONTROLLED FILL
I. GENERAL
These specifications cover preparation of existing surfaces to receive fills, the type of soil suitable for use in fills, the control of compaction, and the methods of testing compac- ted fills. It shall be the contractor's responsibility to place, spread, water, and compact the fill in strict accord- ance with these specifications. A soil engineer shall be the owner's representative to inspect the construction of fills. Excavation and the placing of fill shall be under the direct inspection of the soil engineer, and he shall give written notice of conformance with the specifications upon completion of grading. Deviations from these specifications will be permitted only upon written authorization from the soil engineer. A soil investigation has been made for this pro- ject; any recommendations made in the report of the soil investigation or subsequent reports shall become an addendum to these specifications.
II. SCOPE
The placement of controlled fill by the contractor shall include all clearing and grubbing, removal of existing unsat- isfactory material, preparation of the areas to be filled, spreading and compaction of fill in the areas to be filled, and all other work necessary to complete the grading of the filled areas.
III. MATERIALS
1. Materials for compacted fill shall consist of any mater- ial imported or excavated from the cut areas that, in the opinion of the soil engineer, is suitable for use in con- structing fills. The material shall contain no rocks or hard lumps greater than 24 inches in size and shall contain at least 40% of material smaller than l/4 inch in size. (Mater- ials greater than 6 inches in size shall be placed by the contractor so that they are surrounded by compacted fines; no nesting of rocks shall be permitted.) No material of a perishable, spongy, or otherwise improper nature shall be used in filling.
2. Material placed within 24 inches of rough grade shall be select material that contains no rocks or hard lumps greater than 6 inches in size and that swells less than 6% when compacted as hereinafter specified for compacted fill and soaked under an axial pressure of 160 psf.
,-
,-
- E-l
-
3. Representative samples of material to be used for fill shall be tested in the laboratory by the soil engineer in order to determine the maximum density, optimum moisture content, and classification of the soil. In addition, the soil engineer shall determine the approximate bearing value of a recompacted, saturated sample by direct shear tests or other tests applicable to the particular soil.
4. During grading operations, soil types other than those analyzed in the report of the soil investigation may be encountered by the contractor. The soil engineer shall be consulted to determine the suitability of these soils.
IV.
1.
(a)
(b)
2.
(a)
(b)
(c)
COMPACTED FILLS
General
Unless otherwise specified, fill material shall be compacted by the contractor while at a moisture content near the optimum moisture content and to a density that is not less than 90% of the maximum dry density deter- mined in accordance with ASTM Test No. D1557-70, or other density test methods that will obtain equivalent results.
Potentially expansive soils may be used in fills below a depth of 24 inches and shall be compacted at a moisture content greater than the optimum moisture content for the material.
Clearing and Preparing Areas to be Filled
All trees, brush, grass, and other objectionable mater- ial shall be collected, piled, and burned or otherwise disposed of by the contractor so as to leave the areas that have been cleared with a neat and finished appear- ance free from unsightly debris.
All vegetable matter and objectionable material shall be removed by the contractor from the surface upon which the fill is to be placed, and any loose or porous soils shall be removed or compacted to the depth shown on the plans. The surface shall then be plowed or scarified to a minimum depth of 6 inches until the surface is free from uneven features that would tend to prevent uniform compaction by the equipment to be used.
Where fills are constructed on hillsides or slopes, the slope of the original ground on which the fill is to be placed shall be stepped or keyed by the contractor as shown on the figure on Page 4 of these specifications. The steps shall extend completely through the soil mantle and into the underlying formational materials.
E-2
.- .
-
-
Id)
3.
(a)
0)
(cl
(d)
(e)
V.
1.
After the foundation for the fill has been cleared, plowed, or scarified, it shall be disced or bladed by the contractor until it is uniform and free from large clods, brought to the proper moisture content, and compacted as specified for fill.
Placing, Spreadinq, and Compaction of Fill Material
The fill material shall be placed by the contractor in layers that, when compacted, shall not exceed 6 inches. Each layer shall be spread evenly and shall be thorough- ly mixed during the spreading to obtain uniformity of material in each layer.
When the moisture content of the fill material is below that specified by the soil engineer, water shall be added by the contractor until the moisture content is as specified.
When the moisture content of the fill material is above that specified by the soil engineer, the fill matekial shall be aerated by the contractor by blading, mixing, or other satisfactory methods until the moisture content is as specified.
After each layer has been placed, mixed, and spread evenly, it shall be thoroughly compacted by the contrac- tor to the specified density. Compaction shall be accomplished by sheepsfoot rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of acceptable compacting equipment. Equipment shall be of such design that it will be able to compact the fill to the specified density. Compaction shall be continu- ous over the entire area, and the equipment shall make sufficient trips to insure that the desired density has been obtained throughout the entire fill.
The surface of fill slopes shall be compacted and there shall be no excess loose soil on the slopes.
INSPECTION
Observation and compaction tests shall be made by the soil engineer during the filling and compacting operations so that he can state his opinion that the fill was constructed in accordance with the specifications.
2. The soil engineer shall make field density tests in accordance with ASTM Test No. D1556-64. Density tests shall be made in the compacted materials below the surface where the surface is disturbed. When these tests indicate that the density of any layer of fill or portion thereof is below the specified density, the particular layer or portion shall be reworked until the specified density has been obtained.
- E-3
-
. .
VI. PROTECTION OF WORK
1. During construction the contractor shall properly grade all excavated surfaces ,to provide positive drainage and prevent ponding of water. He shall control surface water to avoid damage to adjoining properties or to finished work on the site. The contractor shall take remedial measures to prevent erosion of freshly graded areas and until such time as permanent drainage and erosion control features have been installed.
2. After completion of grading and when the soil engineer has finished his observation of the work, no further excava- tion or filling shall be done except under the observation of the soil engineer.
-
-
-
-
Remwe all topsoil -J
Slope to be such that sloughing sliding does not occur
' Varies' '\ /
ti- See note
NOTES:
The minimum width of "B" key shall be 2 feet wider than the compaction equipment, and not less than 10 feet.
The outside edge of bottom key shall be below topsoil or loose surface material.
Keys are required where the natural slope is steeper than 6 horizontal to 1 vertical, or where specified by the soil engineer.
note
- E-4
APPENDIX F
GUIDE SPECIFICATIONS FOR SUBSURFACE DRAINS
-
-
I. DESCRIPTION
Subsurface drains consisting of filter gravel or gravel enclosed in filter fabric with perforated
clean pipe shall with these be installed as shown on the plans in accordance specifications, unless otherwise specified by the engineer.
II. MANUFACTURE
Subsurface drain pipe shall be manufactured in accordance with the following requirements.
Perforated corrugated ADS pipe shall conform to ASTM Designa- tion F405. Transite underdrain pipe shall conform to ASTM Designation C-508 (Type II). Perforated ABS and PVC pipe shall conform to ASTM Desginations 2751 and 3033, respect- ively, for SDR35; and to ASTM Designations 2661 and 1785, respectively, for SDR21. The type pipe shall conform to the following table.
Pipe Material
ADS
Maximum Height of Fill (feet)
(Corrugated Polyethylenej 8
Transite 'underdrain'
PVC or ABS: SDR35 SDR21
III. FILTER MATERIAL
20
35 100
Filter material for use in backfilling trenches around and
over drains shall consist of clean, coarse sand and gravel or crushed stone conforming to the following grading require- ments.
Sieve Size
1 I@ 3/4" 3,'8" 4 8 30 50 200
Pcrcfntagc Passing Sieve
100 90 - 100 40 - 100 25 - 40 . 18 - 33 5- 15 o- 7 o- 3
This material generally conforms with Class II permeable material in accordance with Section GE-l.025 of the Standard Specifications Of the State of California, Department of Transportation.
F-l
-
IV. FILTER FABRIC
Filter fabric for use in drains shall consist of Mirafi 140 (Cclancse), Typar (,DuPont), or equivalent. The aggregate shall be 3/4-inch to l-l/Z-inch maximum size, free draining agqrcgate. Filter fabric shall completely surround the aggregate.
V. LAYING
Trenches for drains shall be excavated to a minimum width of 2 feet and to a depth shown on the plans, or as directed by the engineer. The bottom of the trench shall then be covered full width by 4 inches of filter material or with filter fabric and 4 inches of aggregate, and the drain pipe shall be laid with the perforations at the bottom and sections shall be joined with couplers. The pipe shall be laid on a minimum slope of 0.2 percent and drained to curb outlet or storm drain.
After the pipe has been placed, the trench shall be back- filled with filter material of 1-l/2-inch maximum size aggregate if filter fabric is used to the elevation shown on the plans, or as directed by the engineer.
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-
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-
. ‘
F-2
.~ _ -
-
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TYPICAL SUBSUP.FACE DRAIHS
FOR LOCAL SEEPAGE
Compacted Compacted
Filter I.\aterial or
Filter Fabric
6" Perforated Pipe
Drain to Curb Outlet
or Storm Orair,
,-Compacted Native Soil
cut Slope
-7 Filter Fabric
6" hrforated Pipe -.I
Drain to Curb Outlet
or Storm Drain
Line
SeepaGe Lize
Compacted
--‘-Filter Ihtcrial or Filter Fabric
- 6” l'crfor~ Lctl Pipe
Llr~iin to Curl) Outlet
or s Lo!w 01~~1 i I,
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-
F-3
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TYPICAL SECTION
SUBSURFACE DRAINS IN DffiWS
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- TYPICAL SECTION
SUBSURFACE DRAINS IN DRAWS
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0RIG::IAL GROUflD
FILTER FABRIC
ALL AROOUND
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PIPE
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APPENDIX G *.
OVERSIZE ROCK PLACEMENT AREAS (No Scale)
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LEGEND
0 ." Place no oversize rocks in this area. q Oversize rock can be placed in this area.
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NOTES
(1) Oversize rocks are those rock fragments between 2 feet and 4 feet in maximum dimension.
(2) Rocks between 2 feet and 4 feet in size should be pro- perly isolated and completely surrounded by properly compacted soil.
(3) No rocks greater than 4 feet in maximum dimension can be used in fills.
(4) The oversize rock should be surrounded by sufficient fines to obtain proper compaction.
(5) No oversize rock can be placed within 4 feet of finish lot grade or within expected depth of utilities, which- ever is deeper. -
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