HomeMy WebLinkAboutCT 74-06; KAMAR PARK-ADAMS; GEOTECHNICAL INVESTIGATION REPORT; 1976-04-23I
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GEOTECHNICAL INVESTIGATION fOR THE PROPOSED
CARLSBAD·TRACT 74-6
e P/ &-/;;:./ J .p ...s
CARLSBAD, CALIFORNIA
For
Kamar Construction Company
325 Elm Avenue
Carl~bad, California 92008
By
WOODWARD-CLYDE .CONSULTANTS
Consulting Engineers and Geologists
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LETTER OF TRANSMITTAL
SCOPE
fIELD INVESTIGATION
LABORATORY TESTS
TABLE OF CONTENTS
SITE, SOIL AND GEOLOGIC CONDITIONS
GEOLOGIC STRUCTURE
CONCLUSIONS AND RECOMMENDATIONS
LmITATIONS
FIGURE 1 -SITE PLAN
FIGURE 2 -KEY TO LOGS
FIGURES 3 THROUGH 5 -LOGS OF TEST BORINGS
'FIGURE 6-GRAiN SIZE DISTRIBUTION CURVES
FIGURE 7 -FILL SUITABILITY TESTS
FIGURE 8 -CONFINED COMPRESSION TESTS
ATTACHt~ENT I SLOPE STABILITY
ATTACHMENT II -SPECIFICATIONS FOR ,CONTROLLED FILL
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WOODWARD·CLYDE CONSULTANTS@!
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WESTERN REGION
3467Kurtz Street
San Diego
California 92110
Phone (714) 224·2911
WOODWARD-ClYDE CO·NSULTANTS
CONSULTING ENGINEERS •. GEOLOGISTS AND ENVIRONMENTAL SCIENTISTS.
Apj':.i 1 23.,_1976'
Project No. 76-121
Kamar Construction Company
325 Elm Avenue .
Carlsbad, California 92008
.• Attention: Mr. Jerry Rombotis
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In accordance with your request and our proposal dated October 20, '1975,
we have made a geotech~ical investigation at the site of the proposed
Carlsbad Tract 74-6 to be located in Carlsbad, California.
The accompanying report presents the results of our studies including a
geologic reconnaissance, subsurface exploration and laboratory tests, as
well as the conclusions and· recommendations that pertain to the development
of this site. The engineers a'ssigned to this project are Walt Crampton
and Richard P. While of this firm.
If there are any questions concerning this project in'which we m9.Y be of
help, please call or write at your convenience.
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Project No-. 76-121
SCOPE
This report describes an investigation of the unde~lying
geologic and soil conditions at the site of the proposed subdivision to
• be known as CaL]sbad Tract-74-6. located on approximately 3-1/2 acres of
land east of Park Drive and south of ·Hillside Drive in Carlsbad, ·California.
The purpose of the investigation is to determine the general subsurface
• soil and geological conditions at the subject site~ incJuding the pre.sence
of any expansive or compr~ssible soils, which would provide a basi~ for
conclusions and recommendations regarding site prepar:ation arid earthwork.
• specifications, the availability of nonexpansive fill materials, the
sta·bility of proposed cut and fill slopes, the most suitable.type and
depth of foundation and the allowable soil bearing pressures for design
• of foundations.
It is our undersianding that th~ .proposed proj~ct is to include
the grading of the ten lot subdivision to generate nine residential
• building pads surroundjng a small cul-de-sac. One of the· lots is occupied
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by an existing residential structure and.will not be graded with the
exception of _ providi'ng ~ driveway to the resi-dence •. Plans iridi·cate that
• the· nine structures to be constructed on site will have finish floor
elevations ranging from approximately 44 ft to 79 ft (Plan Datum). Wood
frame and stucco constructi on wi 11 be used whh con venti ana 1 foundati·ons
• and slab-an-grade floors. .Plans further indicate that all nine structures
will be split level dwellings. Retaining walls are presently planned
adjacent to Lot 5 and·6 on the.subject subdivision at the toes of proposed
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Project No. 76-121 ?ag~ 2
1-1/2 to 1 cut slopes. We further understand that smaller basement type
-retaining wall's, on the order of 5 ft hi9h ,will separate the garage from
the living portion of the str~cture.
• The ,preliminary ,grading plans indicate that the adjacent
,hillside topography'to the northeast will be'cut back sli9,htly with
maximym sl,ope heights Dn the order of 30 ft and inc1inations.of 1-1/2 to
• 1. The remainder of the proposed grading on site is essentialiy that of
providing split 1,eve1 cut-fill and fill pads for the proposed structures.
Fill slopes throughout the proposed project will b'e less than 10 ft
• in height with inclinations of 2 to 1.
'FIELD INVESTIGATION
A field investigation was performed at"the site on February 2, 1976
• and consisted of a general geological rec'onnaissance of the area and the
drilling of five test borings at the approximate locations shown on the
Site P1~n, Fig. 1. The test borings were drilled with a 6-in. diameter,
• continuous flight, truck-mounted power auger. Representative soi'l
samples were obtained fro~ the auger cuttings and by driving a Standard
California Sampler into the subsurfa~e materia1s at various depths in
• " the test borings. The field studies were conducted under the supervison
of an engineeri~g geologist from our office. The geologist prepared
field logs of the borings on the basis of an inspectioh of the ~amples
• secured, the excavated materi"als, the action of the drilling equipment,
and' the penetrati on res i ?tance "of the sampler. The key to 1 ?9S and the
logs of the test borings presented on Figs. 2 through 5 are based on the
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• results of laboratory tests and the, field logs. The vertical position
of each sample is shown on the Logs ,of Test Borings.
As an aid to our studies, we were provided with a tentative
• map of Carlsbad Tract 74-6, dated ~1arch 26, 1974, and prepared by Weacco,
Incorporated of San Marcos, California. A preliminary Grading Plan and
Plot Plan dated February 13, 1976, prepared by Raymond R. Rfba~ of Brea,
• California was also provided.
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LABORATORY TESTS
, The soils at the sUbject site were visu'ally classified in the
laboratory and, representative ,samples were,evaluated with respect to dry
density and water content, strength, and compressibilitycnaracteristics,
grain size, and plasticity. Classifications 'were substantiated by
• conducting grain size analyses and a plastici'ty test on representative,
'soil 'samples. The strength of the natura1 soils was estimated by consideration
of the d'ry density and mqisture content of the samples, ,the penetration.
• resistance of the sampler and the general geologic characteristics of
the ,various materials. The compressibility of t~e soils was evaluated
by three confined compression tests performed on various representati~e
• soil sampl es. Fi 11 suitabil ity tests, i ncludicng a 1 aboratory compacti on
test, grain size distribution and'a direct shear test on a compacted
sp~cimen, were performed on a sample of a probable predominant fill soil.'
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Results of the moisture content and dry density determinations
a.re shown with penetration resistance of the sampler at the corresponding
sample locations on the Logs of the Test Borings. The results of the
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• Project No. 76-121 " Page 4,
• grain size analyses a,nd plasticity test are shown on ,fi.g. 6, the results
of the fill suitability and confined compression tests are shown on Figs.
7 and 8, respectively.
'. SITE, SOIL AND GEOLOGIC CONDITIONS
The subject site is located in a tributary to Agua Hedionda
Lagoon approximately 2000 ft north of the 1agoon,. The site, being
• approximately 3-1/2 acres in size, includes porUons of the lower easte'rn
canyon side slopes and' the'adjacent valley floor~ Elevations at the
site range from a low of approximately 38 ft to a high of approximately
'. 114 'ft (Plan Datum). The general topography of-the canyon side slope~,
which is characteristic of Lots 5 ~nd-fi, is relatively steep having
maximum slope inclinations on the order of 2 to 1. The canyon floor,
• Lots 1 through 4 and 7 through 10, is relatively level with a south~rly
trending gradient of approxim~tely 10 percent.
The steeper portions of the site are generally covered 'with a
• moderate to heavy growth of brush and native grasses. The remainder of
the site with the exception of lot 2 is presently being ~tilized as an
avocado orchard.
• An existing residence and adjacent garage is located on Lot 2
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of the proposed subdlvision. An exi-sting concrete block retaining wall
is located just offsite paralleling the northern boundary. A cut Whi-ch
is planned on Lot 2 to accommodate a driveway, will be made close to the
edge of this wall. Other man-made features noted on site inclUde a
shallow irrigation system and boundary fences. No water wells, septic
tanks, leach lines or other underground structures such as these wer~
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Project. No. 76-121 Page 5
noted during our investigation; however, these types of man-made features
are typical in older outlying residenti.al' areas and may be encountered
during constructlon.
'Based on an inspection of the natural exposures and the da'ta
obtained from our test borings, it appears th~t the on' site soils may
generally be grouped into four categories, the first two of which ar.e
nonformationa1 in character:.
(a) Fill Soils:. Two existing fills were: identified during
our irivestigation 6f the site. The approximate locations are shown
on the Site Plan, Fig. 1. The largest fill is associated with
previous grading for the existing house. The second smaller fill
appears to b.e shallow and of limited extent. It.is composed of loose
material and is unsuitable in its present condition fOT the direct
support of any additional fill and/or structures .
(b) Natural Overburd~n Soils -Topsoil andAlluvi~l-Colluvial
Topsoil -Natural overburden' soils are encountered beneath the fill.
and natural surfaces of the site. They consist of a tops'oil mantle
of loose porous silty to clayey sand ranging in thickness from 0 to
. 4 ft with a~ average pf 2-1/2 ft.
Lots 6 through 10 are underlain beneath the topsoil by alluvia1-
co n uvi a 1 soil s comp'osed of loose to medi urn dense si lty to cl ean fine to
meqium sands wh·ich are porous-and compressible to varying degrees.
These soils range from 0 to 18 ft in ~hickness.
(c) . Quaternary Terrace Deposits -This formational deposit
Was encountered bel~w the topsoil along the northern por~ion·of the
site, Lots 2, 3, 4 and portions of 5 and 6, cohsists of medium
dense s 1 i ght1y porous si lty sands underlain by very dens.e
clayey sands. This unit appears to nave a maximum thickness
. on the orde~ of'lQ ft and is cOnsidered to be a relatively
competent foundation material.
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(d) Tertiary Torrey Pines Formation,.. This terti-ary age
deposit, which consists of coarse silty to clayey sandstone, is
exposed on the lower northern ~nd eastern side slopes Of Lots 5 and
6 as well as in a stripped area over portions of lots 1 and 2.
This material' extends to significant depths on site and is also
relatively competent in nature.
NO....Qrbundwater was encountered in any of the test borings at
'the time of our field investigation. ,
GEOLOGlC STRUCTURE
'Our ;'nvestigation revealed ,that both formational units, the
• Quaternary terrace and Tertiary sandstone formations, are relatively
horizontally stratified. Our field reconnaissance, drilling, study of
areal photographs and a review of current geologic maps revea1ed.1l.!L-.'
• evidence of existing natural landslides on site, or major fault structures
traversing the property.
CONCLUSIONS AND RECO~1MENDATIONS
• General
(1) The, results of our studies to date, indicate that there
are no major adverse geologic conditions on. site; however, there are
• potentially compressible soils which extend to depths of up to approximately
20 ft over the southern half of the site. The existence of these loose
,soils J.oJhe ar,ea of lots 6 through 10 'will require speci,a1 consideration.
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(2) The general soil conditions on site with their pertinant
characteristics are summarized in the table be16w.
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• Project No. 76-121 Page 7
Physi ca 1 • Material Age Material Characterj sti cs
Overburden Soils Recent Silty sand topsoil. Potenti a 11 ~
Silty to clean sand Comgressible
colluvial-alluvial
soils ... loose to • medium den~e -~orous .
Q,uaternary Terrace . Qua terna ry Silty to clayey sand
medium dense to dense
slightly porous Relatively
Competent • Terti ary Sands.tone Tertiary, Dense si lty to clayey Units
sand
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No groundwater was encountered in the test borings at the time
• of drilling; however, i't,sh'o.uld be anti-cipated that s.ome water may be
encountered in the alluvial soils at depth.
(3). It is our opinion that most of the soils to be used in
• fills Will be nonexpansiv.ein nature.
(4) It is our opinion that the materials i~ the proposed cut
areas 'can be excavated by light to medium ripping with he~vy duty dozer
• equipment.
(5) It i$ our opinion that the proposed cut slopes having
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maximum heights on the order of 30 ft, and slope incli~ations of 1-1/2
• . to 1, will. have adequate indi cated factors of safety against deep-seated
slope failure when const'ructed in 'accordance with the plans and spec.ifications.
Likewise, the 'proposed fill slopes having maximum heights ·of less than
• 10 to 15 ft and slope inc1i.nations of 2 to 1, will also have adequate
indicated factor of· safety against deep-seated slope failure. Ca1culati·ons
are attached to, support our concl~sions. All slopeS should be provided
• with' adequate surface drai'nage and should be properly landscaped and
maintained . No pondinfjshou1d be·allowed above slores. . '
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(6) ·It is recommended that the top of the l-l/ 2 to 1 cut to
be made at the back of Lot 2 be kept a minimum horizontal distance of 10
ft from the base of the adjacent offsite wall. A small retaining wall
• may be required at the toe of the ClJt in'order to.provide sufficient
room for the planned driveway. Recommendations for the design of such
walls are found in a later section (Paragraph 5, Foundation and Retaining
• Halls). As an alternative to this it may be more desirable to move the·
proposed garage and driveway such ~hat the cut is essentially eliminated.
In this case, no special design recommendation would be required.
• Site Preparation and Earthwork
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(1) It is recommended that the site .be .cleared of vegetation
and the resulting material disposed of nff-site. The avocado trees in
areas of grading should be cut off near the ground surface and the stump
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and root system removed in a workmanlike manner .
. (2) .In the area of Lots 1 through 6, it is recommended that
• a 11 loose porous surface soi 1 5 not removed by grad i ng opera ti'ons, be
exca~ated and compacted prior to placing any new fill or foundations.
The maximum depth of loose soils in. these lots is 'anticipated to be on
• the order of 4 ft; however, the actual depth of excavation and compaction
should be' contro 11 ed in the fi e 1 d by the soi) engi neer upon vi sua 1
examination of the exposed soil.
• (3) In the area of Lots 7 through lQ, it is recommended that
the loose surface and alluvial-colluvlal 5..0ils not removed by grading'
operation be excavated to a maximum depth of 5 ft and compacted in
• accordance with specifications prior to placing new fill. Settlements
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Project No. 16-121 Page'g
that may,occur after the construction period due to possible saturation
of soi 1 s are expected to be primarily total settl ements, 'qnd' may be on
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the order of 1 to 2 in. Differential settlements are estimated to be
approxima~ely one-half'of the total sett1~ments.
(4) Potentially expansive soils are not expected to be encountered
during grading of the site; however, should local pockets of tlay occur
near finished grade in areas of cut or shallow fills, it is recommended
that they be undercut to a minimum depth of 2 ft, and pl~ced in the , '
deeper portions of the fill. The excavation should be filTed with . .
• properly compacted nonexpansivesoils available on site. All fill
placed ·within 2 ft of fi'nish grade should consist of ,sele'ct nonexpansive
soi 1.
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(5) It is recommended that all fi 11 slopes be compacted in
,("., accordance with locally'accepted standards, which include periodically
backrolling with a sheepsfoot compactor during construction.
(6) It is recommended that all grading be done in accordance
with the attached Specifications for Controlled Fill. The earthwork
should be done under the observation of and compaction'tests taken by
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'(7) It is recommended that grading plans be reviewed by . .
Wo?dWard-Clyde 'Consultants pri?r to finalizing.
(8) It is recommend.ed that a precons tructi on conference be
held at the site with the owner or developer, 'design engineer, grading
, contractor and soil engineer in. attendance. Any questions regarding
soil handling or grading at ,the site may be answered at that tim~ .
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• Project No. 76-121 Page 10
• Foundations and Retaining Walls
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("l) It is our opinion that conventional spread or continuous
footings founded in a pro.perly compacted ma~ of none,xpansive $oil or
• firm nonexpansive undisturbed natural ground will provide a sui.table
foundatfon for the proposed one and. two-story wood frame and stucco
residential structures on Lots 1 through 6.
• (2) In the case of Lots 7 through 10, due to the variabie
nature of the potentially compres'sible anuvial-colluvial soils at d'epth
below the~e lots, it is our opinion that differential settlements ranging
• from 1 to 2 in~ could take place upon saturation of these soils after
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loads are applied. Structures and foundations on those lots'should
therefore be designed to withstand these settlements.
(3) For preliminary dt?sign, it is recommended that an allowable
soil bearing pressure of 2,000 psf (total dead plus live load) be,used
in the design of footings founded in a minimum depth of 12 in: below
• na tura 1 or cqm'pacted ,grade in soi 1 s as ,specifi ed in Paragraphs 1 and 2
above. The bearing pressure may be increased by one-third for loads
that include wind or seismic 'forces. All footings should have, a minimum
• width of 12 in., and no footing should be located within 5 ft of the top
of the slope. In addition, the foundations for structures on Lots 7
through 10 should be designed for the estimated settlements.
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(4) As an alternative to designing structures for settlements
on,Lots 7 th~ough 10, a pier and grade beam foundation could be provided
with the piers eX,tendin.g through the compressible ,soils' into dense
formati·ona 1 soil s at' depth.
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• For this alternative solution, additional test borings will be
required' in order to establish depth of piers. For preliminary estimating,
pier depths ranging from 15, to 25 ft are anticipated. An allowable soil
• bearing pressure of 4000 psf (total dead plus live load) may be used in
desi~n of piers founded a minimum depth of 3 ft into dense formatiohal
soil underlying the compressible unit. A1l piet~ should have a minimum
• diameter of 30 in. to allow 'for cleaning and inspections. Raised wooden
floor construction is recommended with the pier and grade beam foundation.
(5) It is recommended that an equivalent fluid weight of 300
• pcf be ,us,ed to determine passive .earth pressures in design of footings
or' shear keys re,sisting lateral forces. This assume$ granular on-site
soils in Jront of the base of the footing, and a horizontal sutface for
• the soil mass extending at least '10 ft from the face of the footing o,r
three times the height of surface generating passive pressur~, whichever
is greater. The top 12 in. of material in areas not protected by floor .' "
slabs or pavemehts should not be included in design for passive resistance
of lateral loads. If it is desired to u~e a coefftcient of friction in
conjunction,with passive pressur~s, it is recommended that a friction
• value of .25 be used. If fricti,on is used alone" an allowable friction
value of .35 may be utilized.
(6) ,It is recommended that cantilevered retaining walls with
• level 'backfill ,surfaces be :designed for pressutes exerted by an equivalent
fluid weight of 30 pcf. For walls that are partially restraine.d from
movement at the top, such as basement walls between,split level portions
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• of the structures, an equivalent fluid weight of 30 pcf plus a ,uniform
pressure bf 50 psf should be used in designs. The values assume that
on-site granular soil will, be utilized for backfill, and, there will be
• no surcharge loads such as adjacent footings or vehicle traffic acting
adjacent to the wall.
(7) It is recommended that cantilevered'retaining walls at
• the toe of the p'roposed cut slopes having maxim~m back slope inclinations
of 1-1/2 to 1, ,be des igned for pressures exerted by an equi va 1 ent flui d
weight of 70 pcf. An additional downward load of 25 pcf acting on the
• rear of the wall may be utilized to aid in resisting overturning.
(8) It is recommended that all retaining wans be provided
wi th a' backfi 11 dra,i nage system adequate t.o prevent the bui 1 dup of
• hydrostatic pressure. As an alternate to this, walls may be designed to
withstand hydrosta ti c' pressures.
LIMITATIO~S
• The conclusions and recommendations made in this report are
based on the assumpti~n that the soil, conditions do, not deviate appreciably
from those dis'closed by the test borings. If variations are ~ncountered , .
• during construction, ,we should be notified so that we may make supplemental
recommendations, if this should be'required.
Evaluation and util ization, of soil mate,rials for support of
., structures includes investigation of the subsurface conditions, analysis,
formulation of recommendations and inspection during grading. The soil
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• investigation is not completed unti"l the soil engineer has been able to
examine the soil in excavations so that he ma"y make the necessary-modifications,
if needed. tve emphasize the importance of the soil "engineer-continuing
• his services through" the inspection of grading, including" the constructio.n
.of fills and f6undation excavations.
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Existing
Structures
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LEGEND: .
Indicates approxim~te location of
test bori.ng ..
Indicates approximate existing
ground surface contour.
Indicates approximate limits of
exi sti'ng fi 11 .
Indicates approximate limits of
Alluvial-Colluvial Soils
SITE PLAN.
CARLSBAD TRACT 74-6
::::::::'~o<:-'--Property Line
Sca 1 e: 1" = 100 I
DRAWN BY: ALS CHECKED BY: PROJECT NO: 76-121 DATE: .3-29-76. flOURE NOi 1 .
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Location Boring' Number . Elevation.
DEPTH TEST DATA ~OTHER SAMPLE SOl L DESC'RIPTION IN
FEET -Me -00 -sc TESTS NUMBER
12
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Ho 65 1
2
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Very dense, damp, brown silty sand (SM)
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WATE:LEVEl ]
At time' of drilling or as indicated.
SOIL CLASSIFICATION
. Soil Classifications are based on the Unified Soil Ciassification System-
and include color, moisture and consistency,. Field descriptions'have
been modified to reflect results of laboratory analyses where
appropriate,
~DISTURBED SAMPLE LOCATION
Obtained by collecting the auger cuttings in. a plastic or cloth bag •.
'--"-----UNDISTURBED SAMPLE LOCATION
MODIFIED CALIFORNIA'SAMPLER
Sample with recorded blows per foot was obtained with a Modified
California drive sampler' (2" inside diameter, 2.5" outside diameter)
lined with sample tubes. The S!lmpler was driven into the soil at the
bottom of the hole with a 140 pound hammer falling 30 inclies.
~--------'---INDICATES SAMPLE TESTED FOROTHER PROPERTIES
GS-Grain Size Distribution cT -Consolidation Test
LC -Laboratory Compaction . UCS -Unconfined Co-mpression Test
Test
PI -Atterberg Limits Test OS;... Direct Shear TeSt
ST -Loaded Swell Test TX-Triaxial Compression Test
CC -Confined-Compression
Test
NOTE: In this column the results of these tests-may be-recorded
where applicable.
~-..,..------BLOW COUNT
Number of blows needed to'advance sampler one foot or as indicated.
'-------------.,----DRY DENSITY Pounds per Cubic Foot
L...-_____ ..,.....,..~ _____ MOISTURE CONTENT
Percent of Dry Weight
NOTES ON FIELD INVESTIGATION
1, REF USAL indicates the inability to ex te nd excavation,:practically,
with equipment being' used in the investigation.
DRAWN BV: ALS CHECKED BY:
KEY TO. LOGS
CARLSBAD TRACT 74-6
_ 'ROJECT NO: FIGURE NO:
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DEPTH TEST DATA *OTHER SAMPLE IN TESTS NUMBER . FEET *MC *DD *BC
4 1-1
GS,DS i -4
LC
25 1-2
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6 114 70 1-3
10
35 1-5
15
Boring 1
SOIL DES C RI P T ION
Very lapse to loo!?e, damp, dark brown
silty sand (SM)
Medium dense, damp, da r k -brown silty sand
SM) Porous
Very dense, damp, brown clayey sand -( SC)
Dens-e, -damp, brown clayey sand (SC ) with
gravel
Bottom of-Hole
Boring 2
DEPTH
'IN TEST DATA' -OTHER SAMPLE SOl L OESeRI PTI O-N
FEET -Me -DD' -BC TESTS NUMBER,
2
22
5
T9 CC
10
20
15
--For doscription of symbols, _sea Figure 2.
DRAWN BY: ALS CHECKED BY:
2-1
2-2
2-3
2-4
Very loose, moist, brown-silty to clayey
sand (SM-SC) Topsoil
Medium dense, damp, brown silty sand (SM)
Porous
slightly porous
Bottom of Hole
LOGS OF TEST BORINGS 1 AND 2
CARLSBAD TRACT 74':'6
PROJECT NO; 76-121
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'DATE: 3-26-76 FIGURE NO: 3 --Ca'\
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DEPTH TEST DATA *OTHER IN "BC TESTS FEET . *MC *DD
6 CC
10
5
11 115 12
10
7
15
15
20
• For description of symbols, see Figurl! 2.
SAMPLE
NUMBER
3-1
3 .. 2
3-4
3-3
3-5
3-6
Boring 3
SOIL DESCRIPTION
Very loose to loos~, moist, dark brown
silty sand (SM) Topso~l
. -Loose to medium denseJ damp, light yellow~
brown sand (SP)
Loose to medium dense, damp,-brown clay~y
sand (SC)
~fi-ne to medium sand (SP)
Loose to medium dense, damp, d9.rk brown
si1 ty sand (SM-SP)
Bottom of Hole
LOG OF TEST BORiNG 3
CARLSBAD TRACT 74-6 -
DRAWN BY: 1\1..5 I CHECKED BY:J4'1'1 PROJECT NO: 76-121 I DATE: 3-26-76 I FIGURE NO: 4 ~
WOODWA-RD·CLYDE CONSULTANTS\§!
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Bor.i ng 4
DEPTH *OTHER SAMPLE IN r--....----.-~. SOIL DESCRIPTION TESTS NUMj3ER FEET ~~ ____________________ ~ ____ ~ __ ~ ____ ~
12 115 4-1
4-2
5
9 4-3'
10
9 4-4
15 -;---+--1---+--+----'--
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DEPTH TEst DATA . *OTHER SAMPLE IN ....,.--.---,..----1 FEET *MC *00 *Be TESTS NUMBER
9 117 38/6" GS 5-1
5
10
13
-For description of symbols, see Figure '2.
Very loose, d9mp, dark brown silty to
clayey sand (SM-SC) with roots Topsoil
Medium dense, damp, yellow-brown silty
fine sand (SM) Porous
Loose, damp, brown silty sand (SM)
Slightly Porous
Loose to medtum.~ense, damp~ yellow-brown
fine sand (SP)
Bottom of Hole
. Boring 5
SOIL DESCRIPTION
Very dens.e, damp, 1 i g ht ye 11 ow-brown
clayey coarse sand (SC)
Bottom of Hole
lOGS OF TEST BORINGS 4 AND 5
CARLSBAD TRACT 74-6
DRAWN BY: ALS I CHE.CKED BY:~PROJ.ECT NO: 76-12i I DATE: 3-26-76 J FIGURE NO: 5.· ~
WOODWARD·Cl VDE CONSULTANTS ~ .
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0 z: -(I) en -< a..
I-z: w
U 0:: W a..
COBBLES GRAV.EL SAND.
S If.. T and Cl.:AY Coarse I Fine CoarsJ Medium J Fine
Mesh Open.ing -ins. Sieve Sizes Hydrometer. Analysis
I I
100 7 6 3 2 I~ .1 .1 lj. 10 162030 1W 60 80 140 200 0 .........
. , ,
\ \
90 \-., 10 \"
\
\
80 \ 20 \'
70 1\ . 30
~ 0 UJ 60 40 ~
\ 1\ < ti \ 0::
50 I-
4-2 50ffi 'U 0:: \. UJ
\ a..
40 \ . \ 60
5-1
.. '-
30 , 70 '1·' ;\ ~
1'\ '" ..... . ......
20 ....... . 'S. r-.. 1" 1 ... 4' .
10
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100 50 10.0 5.0 1.0 0.1 0.05
GRAIN SIZE IN· MILLIMETERS
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SAMPLE CLASSIFICATION AND SYMBOL
1 - 4 . S1 lty sand (SM)
4 -2 Silty sand (SM)
5 -1 Silty sand (SM)
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*LL ::: Liquid Limit
*PI = Plasticity· Index
GRAIN SIZE DISTRIBUTION CURVES
CARLSBAD TRACT 74-6
.........
........ 80 ~~ --~ -... ---........ ...... ""'"-90 . ~
-.....;: ...
100
0.01 0.005 0.001
*LL *PI
----
-... --
Non P astic
DRAWN BY: ALS I CHECKED BY:~ PROJECT NO: ._76-121 I DATE:. 3-'26-76 I FIGURE. NO: 6 .
. WOODWARO·Cl VOE CONSUL TANTS~-
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1.50
14 0
13 0
12 a
110
100
90
PLASTICITY CHARACTERISTICS
Liquid Limit, %
. Plasticity Index, %
Classification by Unif.ied Soil
Classification System
, \ i\ .
1\ \ 1\ ZERO A!R VOIDS CURVES
\ 1\ ' \" 2.80 SG
\ 1\ 2.70 SG
\ 1\ 2.60 SG
2.50 SG \ !\ , \
\ 1\ '
\ \ ~
\ i\ ' .\ \\ 1\
\ \ 1\
. \ 1\ \
/ ~ \ 1\
\ ~ \ \ --.,> V \,\ 1\\ 1-4
I \ \1\
.... \ \ \\ u \\ \ 1\ 0.
1-' \ \ J: 1\ (!). \\ \ K jjj
~ \ \ 1\\ . I-
z \ ~ ::> \ 1\ ~ 1\
0: r\ .\ 1\ 0 :
'\ 1\'
·1\ r\' ,,\
\
Maximum Dry 1-4
Density, pcf 126.0
Optimum Moisture
Content, % 10.5
1 .1 1 . I MOISTURE CONTENT, %
19 20
f SILT & CLAY .
100 ~ ,
:\
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0: ~ 2
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.] -~ "-'j "-t-
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1000 100 10 1.0 0.1 0.01 0.001
·GR,A;IN SIZE, mm
MECHANICAL ANALYSIS
DIRECT SH EAR TEST DATA 1-4
Dry Density, pcf ." 3
Initial Water Content, % .
Final Water Content, % . J 4
. Apparent Co hesion, pst' 120
Apparent Fri ction Angle, degrees 33
SWELL TES T DATA
. Initial Dry D ensity, pct
Initial Water Content, %
Final Dry Oe nsity, pet
Final Water C ohtent, %
f-.Load i psf
\\ Swell, percen t
,\ i\ ~\ f\. " 1\ 1\ r-..\
.~ .\ f\ r\> l'\ I\.
'\ ~'\ """-'\ 1\:. tV
1,\ r\ t\."\
.~ ~1
30 40 LABORATORY COMPACTION
LABORATORY COMPACTI9N TEST TEST METHOD: ASTM-D .,1557-70
FILL SUITABILITY TESTS
CARLSBAD TRACT 74-6
DRAWN BY: ALSI CHECKED BY:Jft1I11 PROJECT Np: 76-12.1 I DATE: 3-26-76. I FIGURE NO: . 7. . WOODWARD~CLYOE CONSULTANTS @ . . '
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Sample
t.umber
2-3
3-1
4-2'
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3
5
6
7
RESULTS OF CONF I NED COMPRESS ION, TE'STS '
Initial Final
Dry Water * Dry , Water * Density Content Saturation Density Content Saturation Pressure Compression
pef % %' ' ' pet % % psf % of I n,i tral Height
100 6 27 106 18 85 2000 6.0
109 13 6,5 110' -16, 80 1000 1.1
98 5, 19 103 19 82 T500 4.4
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, PRESSURE -psf
o '160 500 1000 1500 2000
__ :b""-,' Wa ter
_r-:V Z Added
r-__ ~H 3-1-
4 -2 -l--4-i!A
* Based on a Specific Gravity of 2.65 , ,
CONFINED COMPRESSION TESTS
,CARLSBAD TRACT 74-6
~ 2-3
DRAWN BY: ALS I cHEeKEDBY:~PROJECTNO: 76-121 J DATE: -3-26-76 J fIOURENO: 8 ;::;))
WOOOWARO~CL YOE CONSULTANTS ~'
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Project No. 76-121
Assumptions:
SLOPE, STABILITY
CARLSBAD TRACT·74-6
Cut and Fill 910pes
(1) Maximum height of. slopes,
(2) Ma'ximum slope inclination,
(3) Unit weight of soil,
(4) Apparent ang1e of internal friC'~ion,
(5) App~rent cohes i·on,
(6) No seepage forces.
Reference:
H
, S =
Y (pef)
~ . '(P;f~
ATTACHMENT I
page 1 of 1
CUT
30
1-1/2':1
130 .
35
500
(1) Janbu, N., IIStability Analysis of Slopes with D;-mension1ess
Parameters", Harvard Soil Mechanics Series No. 46, 1954.
Analysis: (Cut Slopes)
Safety Factor, F.S. =. Ncf y~.
y' H tan p
c = 130 x 30 x
500
Where N f ;-s' the s tabil ity No. ,c
for slopes with both c and ~.
.7 .= 5.46
From Fi gure 3-1 . of Reference: Ncf = 18,
18 x tiOO F.S. = '130 x 30 =. 2.30 OK
(Fi 1] Slopes)
Acf = 130· X lO x .649 = 7.03 120
Ncf = 25
25 x 120 F.S. = = 2.31 OK 130,x TO ._-
FILL
10
2: 1
, 130
33
120
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Project No. 76-121 ATTACHMENT .II
Page 1 of 4
• SPECIFICATIONS FOR CONTROlLED FILL
I. GENERAL
TheSe specificat{ons cover preparation of existing surfaces to r~ceive
fills; the type of soil suHable for use in fills; the control of com..,.
• paction and the methods of testing compacted fills. It sha'1l be the
Contractor1s responsibility to place, spread, water a'nd compact the fill
in strict accordance with the'se specifications. A Soil Engineer s·ha 11 be
the OwnerlS representative to inspect ·the construction of fills. Exca-
vation. .and theplacing<of fill shan be under the direct i.nspection of
the Soil Engineer and he ~hall1 give written notice of conformance with
• ". the specific.ations 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 project;
any recommendations made in the report of the soil investi.gation. or
subsequent reports shall become an addendum to these specifications.
• I I. SCOPE
The placement of controlled fill by the Contractor shal1 include all
clearing and grupbing, removal of eXisting' unsatisfactory materia'l,
preparation of the areas to be filled, spreading and ~ompaction of
fill in the areas to be filled; and all other work necessary to complete
• the grading of the filled ·areas. .
III. MATERIALS
l. MaterialS for compacted fill shall ~onsist of any material imported
or excavated from the cut areas that, in the opinion of the Soil Engineer,
• is sUitable for use in constructing fills. The. material sh'all contain no .
rocks or hard lumps greater than 6 ~nches in size and shall contain at
least 40% of material smaller than 1/4 inch in size. No mate'rial of a
'perishable, spongy, or otherwise improper nature shall be used in filling.
. . 2. Material placed within 24 in~hes of rough lot grade s~all be select
• material that contains no rocks or hard lumps greater than 6 inches in
. size and that swells less than 3% when compacted as' hereinafter specified
for compacted fill and when subjected to an axial pressure of 160 psf.
3. Representative samples of materi.al to be used for fill shall be tested
in the laboratory by the Soil Engineer in order to determine the maxi,mum
• density, optimum moisture content a·nd classification of the soil. In addition,
the Soil Engineer shall determine the apprQxi,mate bearing value of a recom-
pacted, saturated sampl e by ·direct shear tests. or other tests appl icable to
the particular soil.
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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 .
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Project No. 76-121 ATTACHMENT IT
, Page 2 of 4
IV. COMPACTED FILLS
1 • General
3.
(a) Unless otherwise specified, fill material shall be compacted
by the Contractor wh il e at a moi sture content near the optimum
moisture content and to.,a density that is r.lot less than 90% of
the maximum density determined in accordance with ASTM Test No.
D1557-70L or other density methods that will obtain equivalent
results.
(b) Potentially expansive soils may be used ,in fills below a depth
of 24 inches and sh q 11 be compa.cted at a moi sture content greater
than the optimum moisture content for the material.
Clearirig and Prep~ring Aieas to:be Filled
. (a') All trees, brush, grass and other objectionable material shall
be collected, piled and burned or otherwise disposed of by the Con-
tractor so as to leave the areas that have been cleared with a neat
finished a~pearance fre~ from unsightly debris.
(b) All vegetable matter' and objectionable material ,shall be removed
by the Contractor from th~~urface upon which the fill is to be placed
ahd any 100se and porous soils shall be removed or compacted to the d~pth shown on the plans. The surface shall th~n be plowed 'or scarified
to a minimum depth of 6 inches until the surface is free from uneven
fea tu res tha t wou 1 d" tend to prevent u.nHbrm compact i on by the equ i pment
to be used.
(c) WHere fills are constructed on hillsides or slopes, the slope of
the original ground on which the fill ts to be placed shall be stepped
or keyed by the Contractor as sho\yn on the attached figure. The steps
shall extend completely through the s'oil mantle and into the underlying
formation'materials.
(d) After the foundation for the fill ha~ been cleared,plowed or
scarified, it shall be disced or bladed by the Contractor ,until it is
uni form and free from clods" brought to the proper moi sture content and
compacted as specified for fill.
Placing, Spreading, and Compaction 'Fill Material
(a) The fill material shall be plqced ~y the Contractor in layers that
when compacted shall not exceed 6 incll'es. Each layer shall be spread
evenly and shall be thoroughly mi'xed during the spreading to obtain
uniformity of material in each layer.
(b) Wheri the moisture content of the fill mat~rial is above that
specified by the Soil Engineer, the fill material Qhall be aerated'
by the Contractor by ,bl?ding, mixing or other satisfactory methods until
the, 1110is ture content is as specifi ed.
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V.
Project No. 76-121 ATTACHMENT II
Page 3 of 4
(c) When the ~6isture content of the fill materi~l is below that
specified by the Soi 1 Engineer, water shall be addeQ by the Con-
tractor until the mo,i sture content is as speci fied.
(d) After each layer has been placed, mixed and spread evenly, it
shall be thor.ough~Y,:' compacted by the Contractor to the specified
density. Compaction shall be accomplished by sheepsfoot rollers, '
vibratory roller, multiple-wheel. p~eumatic-tired rollers or other
types of acceptable comp'acting equipment. Equipment sha·ll be of such
d~sign that it will be able to compact the fill to the specified density.
Compaction shall be continuous over the entire area and the e~uipment '
shall make sufficient trips to insure that the desired density has been
obtained throughout th~ entire fill .
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(e) Surface of fill slopes shall ,be compacted and there'shal1 be no
loose soil on the sl~pes.
INSPECTION
1. Observations and compaction tests shall be made by the Soil Engineer
during the filling and compaction operations so that he can state his
opinion, that the fill was constructed in accordance with the specifications~
2. The so'n Engineer shall make field density tests in acco.rdance with ASTM
Test No. 0-1556-'70 •. 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 portions shall be reworked
until the ~pecified density bas been obtained. '
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 fi ni shed \o'JOrk on thE! site. The Contractor sha 11 take remedi a 1
measures to prevent erosion of freshly gr~ded areas and until such time
as permanent, drainage and eros,ion control measures have been installed.
2. After completion of grading and the Soil Engineer has finished his
observations of the work~ no further excavation or filling shall be
done except under the observation of the Soil Engineer .
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NOTES ---
Remove all
The minimum wid th ''B'' of key sh.;lll· be 2 fee t \\'ider than
the compaction eq~ipment, and not less than 1(1 feet.
The outside edge of bottom key shaH be beloy] topsoil
or loose sur face IDa terial.
Keys are require~ where' the natural slope is f teeper
than 6 horizontal to 1 ver'tical, ot where spec:i.fied by
_ Soil Engineer.
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Gro'Jnd
Slope Ratio N
M
il:
~ see
B
Note 4
• • Fr.,~, •
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-0 ~ o
~. ro () c+
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N --'
-0 )::0 PJ-I
,(,0 -I ro)::o
CJ
.j:::. :c ::s: Orn -t, ::z
.j:::.-I
I-f
I-f
'= a_.a-~ __ ~ ____________________ ~~~ __________________ ~~ ______ ~
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