r'··gmw.consrv.ca.gov/shp/apsi_siteinvestigation... · 6/27/1975 · .dth district thomas...
TRANSCRIPT
David W, C•rp•nter County of Al•meda · Public Works Building RoC!lll ' "1 399 Elmhurst Street H•yward, California 9451i4
Daar Hr, Carpenter:
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(415) 557-0413
No'lelllbllert, 1976
Thcl Terrasearch lnwstlgatlon for the Krudop homeslte; Pleasanton, has been received and placed In our Informal Con$Ultlng file,
Thanks for your consideration,
EWH/mkr
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Slnc:e.-.ly yours,
EARL W, HART Geologist San Francltco District Office
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COUNTY ! . -
OF i' ALAMEDA AlAM!DA COUNTY
PUBLIC WORKS &UILDING ROOM 141
399 ELM HURST STREET HAYWARD, CALIFORNIA 94S44
881-6423
Mr. Earl W. Hart California Division of
Mines and Geology FeJ:>ry Building San Francisco, Ca 94111
Dear Mr. Hart:
Octobel:' 25, 1976
BOARD Of: SUPfRVISO~S
JOHN D. MURPHY lST DISTRICT
CHAl?C.ES SANTANA 2ND DIS'fl~ICT
f=RED F. COOPER 3RD DJSTRJCT
JOSEPH P. BORT .dTH DISTRICT
THOMAS H. BATES 5TH DISTRICT
HERBERT C, C:ROWlE DJRJ;CTO~ Of PU8UC WORKS
Enclosed is a copy of a Soil and Geologic Investigation report prepared for a single family residence on Foothill Road, Pleasanton area of Alameda County. The report was requiJ:'ed under provisions of Chapter 29, Alameda County Building Code and meets the requirements of the Code. It was not reviewed for conformance with the guidelines for geologic reports under the Alquist-Priolo Act but since the report does provide geological observations in close proximity to the Calaveras Fault, this extra copy is being sent to you for filing and use as may prove appropriate.
The site location, as shown on Figure 2 in the report, is on the east side of Foothill Road, about 2,200 feet south of the intersection of Foothill Road and Castlewood Drive, Dublin, California 7-~ minute quadrangle.
VeJ:>y truly yours,
fl~ w ~~L\ DWC :gh David W. CaJ:>penter
Alameda County Engineering Geologist
ALAMll:CIA "' AL•AH"~ .. 111~ .. KIELKV .. EM~R'rVILLE • F~~"'Of'(T • H.o.vwo11i1110 • l,.lvEftl,(ORIC ill i'IEW.O.RIC • OAKLANti • P!~OMOMT • PLll:"i;S;ANTON
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SOILS AND GEOLOr.Ir. INVESTIGATION on
PROPOSED HOH!lSITE Foothill Boulevard
Pleasanton, California
for
MR. KRUDOP (c/o Allied Brokers) D,, ";s '·1
By
TERRASEARCH, INC • Project No. 1273-E
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TERRASEARCH, INC.
SOIL, FOUNDATION AND GEOLOGICAL. ENGINEERS
1580 NORTH rouATH $TAE:ET SAN JOSE, CALIFORNIA 95112 (408) 287-9460 2129 HACIENDA WAY SACRAMENTO, CALIFOFINIA 9582.5 (916) 4B3.-8402
Mr. Dan Gamache c/o Allied Brokers 3730 Hopyard Road Pleasanton, California 94566
Subject: Proposed l!omesite Foothill Road Pleasanton, California
Project No. 1273-E 11 March 1976
ADDENDUM TO SOIL AND GEOLOGIC INVESTIGATION
Dear Mr. Gamache:
In response to your request, TERRASEARCH, INC., has reviewed and republished our report for the prcpo~ed homesite on Foothill Road. We find that the current building concept is feasible.
The relocation of the house to a more easterly location is, from a seismic hazard vie1<point, an improvement. However, the relocation of the home, when considering the aspect of f oundati.on design, requires some additional considerations be met. The relocation of the house will place the foundation at or near the banks of the abaudoned stream channel near the rear of the original homesite. A certain amount of uncompacted fill has been placed along this bank.
If foundations are placed in or near this bank, the fill should be removi=d, the native ground prepared, and the material replaced as compac:ted fill in accordance with Paragraphs 6 through 10 of the enclosed report. As an alternate, deep pie.r foundations should be used in this area.
The pters should penetrate the fill and be excavated a mlnimum of five feet into the firm natural ground benenth the fill. All other design and construction factors should be in accordance with Paragraph 13 of the enclosed report.
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Project No. 1273-E 11 March 1976
It is our opinion, based on the data gathered, that the site is sa·fe from landsliding providing that the nature of the site remains the same and that the recommendations of this report and letter are followed~ The settlement of any fills placed in accordance with the provisions of this report should be negligible, The fill noted along the stream will settle under stresses, possibly beyond the limits of structural tolerances. Recommendations to minimize this effect have been given.
In the case of unusual storm activity, some flooding and erosion may be anticipated along the old stream channel, It is recommended that the recommendations of the Flood Control District be followed.
Should ·you have any questions concerning the contents of this report 'or should additional information be required, please contact this office at your convenience .
Reviewed by:
CM:HA:ld
Copies: 2 to Hr. Dan Gamache
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Very truly yours, TERRASEARCH, INC.
~ ")/l.Uv.J<A1 Curtis ifessing f; E.G. Senior Enginee.ing Geologist
Hassan Amer, P.E. Principal Engineer
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TERRASEARCH, INC.
SOIL, FOUNDATION AND GEOLOGICAL ENGINEERS
1580 NORTH FOl,JRTH STREET SAN JOSE, CAUFOFINIA 95112 (408) 287-9460 212S HACIEi:NDA WAY SACRAMENTO, CAl.IFORNIA 9582~ (918) 483-9402
Mr. Jerry Krudop c/o Allied Brokers 3730 Hapyard Road Pleasanton, California 94566
Subject: Proposed Homesite Foothill Boule.vard Pleasanton, California SOIL AND GEOLOGIC INVESTIGATION
Dear Mr. Krudop:
Project No. 1273-E 27 June 1975
In response to your authorization, TERRASEARCH, INC., has completed a Soil and Geologic Investigation on your proposed homesite located in Pleasanton, California.
The data gathered during our investigation indicates that the site is not crossed by any tract of the Calaveras Fault and that the site may be developed for the construction of a single-family, one or two-story frame residenco. This feasibility is based upon adhere11ce to the design and construction procedures as outlined in the enclosed report.
Should you have any questions concerning the contents of this report, please contact this office at your convenience .
CM:HA:mer cc: Mr. J~rry Krudop (4)
Very truly yours, TERRASEARC!I, TNC.
~b;-Curtis Messinger -'-1 C.E.G. 674
Hassan Amer R.C.E. 19674
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Project No. 1273-E 27 June 1975
TABLE OF CONTENTS
LETTER OF TRANSMITTAL
SOIL AND GEOLOGIC INVESTIGATION
Purpose and Scope Proposed Construction Methods of Investigation Surface Soil Conditions General Geology Site Geology
DISCUSSIONS AND CONCLUSIONS
Conclusions
RECOMMENDATIONS
General Grading of the Site Foundations Perimeter Footings & Interior Spread Footings Pier and Grade Beam Foundation Systems Concrete Slabs-on-Grade General Construction Requirements
LIMITATIONS AND UNIFORMITI OF CONDITIONS
LITERATURE RESEARCH
APPENDIX A
Site Plan (Figure No. 1) Location & Geology (Figure No. 2) Logs of Test Borinr,s (Figures No. 3 and 4) Summary of Lah Test Results (Table 1) Aerial Photo Lincation (Figure No. 5)
APPENDIX B
Geophysicist's Report
Page No.
1 1 1-4 4 4-5 6
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10 10 10-11 11-12 12
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Project No. 1273-E 27 June 1975
SOILS AND GEOLOGIC INVESTIGATION
Purpose and Scope
The purposes of this investigation were:
a) To determine if any active branch of the Calaveras Fault crosses the proposed homesite;
b) To provide those design data determined by geologic and soils conditions which are necessary for completion of the project •
The data used in the analysis phase of this investigation were gathered by
means of a study of geologic maps, aerial photographs, test borings, and
laboratory •
Proposed Construction
At the time of our i.nvestigation, the construction of a two-story,
wood-frame house was anticipated •
Methods of Investigation
In addition to a reference to the available literature on the site
and its environs, the project site was studied by means of stereoscopic
inspection of aerial photographs test borings, geophysical exploration,
and laboratory testing.
Aerial Photograph Study_: The aerial photographs use.d in this study were
flown in 1957, and printed at a scale of one-inch equal to 1,000 feet.
These photos were studied under thi= St<'.reoscope for lineaments (indicative
of faulting), landsliding, seepage areas, areas of potential ins tahility,
and any other pertinent features •
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Project No. 1273-E 27 June 1975
Subsurface Exploration: The subsurface exploration was accomplished by
~ans of a truck-mounted earth auger utilizing a six-inch diameter bit •
The purposes of this exploration were as follows:
4) to determine the subsurface stratigraphy on the site; and
b) to obtain soil and/or rock samples for testing in the laboratory .
Undi$tYrbed soil samples were obtained by hydraulically pressing or ·
6riving t:he sampling device into the undisturbed material at the bottom
of the drill ho:e. These samples were sealed in tubes and forwarded to
the laboratory for testing. All drilling was done under the supervision
of a member of our staff •
The locations of the borings are shown on Figure No. 1, and the "Log
Qf !eH Borings" is given as Figure No, 2, Appendix A •
Geophysical Exploration: Allied Geophysics of San Jose was retained in
order to supplement the information gathered during the trenching and
~ite inspection. The geophysicist's report is reproduced in its entirety
as Appendix B of this report. The conclusions of the ge.ophysicist were as
follows:
No fault trace was detected •
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Project No. 1273-E 27 June 1975
Laboratory Testing: The laboratory testing for this investigation was
progrannned to evaluate the on-site soils in relation to bearing values,
and other design criteria determined by soil and/or geologic conditions.
The following tests were used:
Moisture-Density Determinations: These determinations are performed
from the volume weight ratios of the particular samples ·before and after
oven drying. The natural moisture and density, or unit weight, of the
subsurface mate.rials is basic to the determination of strength parameters
and grading criteria •
Unconfined Compressive Test: Determined usually on soft to stiff
clays. It is approximately equal to twice the shear strength of the
clays tested and is performed by axially stressing a sample to the failure
point, The failure stress is indicative of allowable foundation bearing
value, and is used in the determination of slope stability determination •
Direct Shear Test: This test is performed by ;:angentaly stressing a sample
under progressive normal loads. It is also indicative of shear strengths.
Atterberg Limits Determinations: Atterberg Limits are determined by the
correlation of consistency changes with 1noisture changes. The Plasticity
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Project No. 1273-E 27 June 1975
Index, a direct derivative of the Atterberg Limits, is indicative of the
expansion potential of the soil tested •
The results of the laboratory testing are given in Table I. In addition,
the natural moisture contents and dry densities are presented in the Logs
of Test Borings.
Subsurface Soil Conditions
The homesite is, according to our borings, unlain by silts and clays in
the near surface areas. Below this are found sandy, silty Clays with
some gravels typical of buried channels 1rnually found in alluvial plains .
The water level in boring No. 2 was found to be at a depth of 19 feet.
General Geology
Helly et al indicate that the site i8 underlain by "young fluvial deposits
consisting of a variety of unlithified granular to colloidal, locally
drained sediments. These sediments on the site itself are, from all indi-
cations, a combination of flood plain deposits related to the ephemeral
stream which crosses the prop,,,rty and co;_luvium generated by the hillside
to the west .
The site is within the special studies zone as designated by the California
Division of Mines and Geology in conformance with current directives. 'l'his
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Project No. 1273-E 27 June 1975
zone is defined by a bond and on either side of the mapped traces of the Calaveras
Sunol Fault. In the area under investigation, two traces have been mapped •
This does not necessarily indicate that two traces of the fault are present.
It does indicate, however, that two researchers have placed the fault along
two lines and therefore the exact locaticn of the Calaveras Fault is in
doubt.
Hall (1959) has placed the Calaveras Fault as sub-parallel to Foothill
Road and possib~y just west of the street in the area of the proposed
building. The special studies zone map places a possible trace of the
fault along the eastern edge of Foothill Road. This postulated trace was
evidently drained from Ford's Groundwater St:udy of the Pleasanton, Sunol
and Livermore Valleys (see Figure No. 2).
To summarize, no available published maps indicate that the proposed
homesite is crossed by a trace of the Calaveras Sunol Fault .
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Site Geology
Project No. 1273-E 27 June 1975
The borings drilled for the foundation investigation phase of this study
tended to confirm the mapped Late Cenozoic Geology of the site.
Dui:ing the study of aerial photographs of the area, which was performed by
Murray Levish in consultation with Terrasearch, Inc., (October, 1971), a
lineament crossing Oak Lano was noted. This was mapped as approximately
SO feet to the west of Foothill Road. This lineament has been plotted
on Figure No. 5 which is a print of an infra-red photograph made in 1972 •
Burton Rose (personal communication) indicates that the Calaveras Fault
passes through the slope at Castlewood Country Club and passes through
the barn across the site and, hence, to the south. This corresponds· with
observed lineaments •
During the geophysical phase of this study, the traverse was so located
as to cover the buildable portion of the site and extends into the right-
of-way of Foothill Road beyond setback requirements .
No indications of faulting were noted on the site in the area between
Foothill Road and the creek channel. If a normal setback from Fo"thill Road
is used, the house. will be a minimum of 50 feet from any active fault as
defined by geophysical means. This data is confirmed by the test. bori.ng
data .
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Project No, 1273-E 27 June 1975
DISCUSSIONS AND CONCLUSIONS
The conclusions derived from this study are:
1) There is no evidence from the techniques used which would indicate
that a fault crosses the part of the site studied,
2) The house will be located in a seismically active area. Earth-
quakes may be expected along the Calaveras Fault; and, although all evidence
indicates that the house is outside the expected rupture zone, accelerations
in excess of O.? g. may be expected.
3) A certain amount of risk is involved in any building project in
the San Francisco Bay Area. However, the construction of a well-founded,
properly constructed structure should tend to minimize such risks •
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General
Project No. 1273-E 27 June 1975
RECOMMENDATIONS
1. It is our conclusion, based upon the geophysicist report, that no
active trace of the Calaveras Fault crosses the proposed building site •
2. The site may be developed for the construction of a single-family
one or two-story frame dwelling providing design and construction are
accomplished in accordance with the recommendations given in this report.
3. It is anticipated that no differential settlement will occur during
the life of the structure,
Grading of the Site
4. Other than that necessary to establish the building pad, the grading
should be limited to what is absolutely necessary to assure proper surface
drainage and ininimi;,:e disturbance of the existing hill.side slopes •
5. The Soil Engineer should be notified a minimum of two working days
prior to the commencement of clearing or grading operations in order that
he may coordinate the work in the field with that of the grading contractor
and review site conditions as related to the proposed grading.
6. All organic growth, contaminated topsoil, and other debris should be
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Project No. 1273-E 27 June 1975
removed from the building pads, driveways, and parking areas prior to the
grading operations. The depth of contaminated topsoil may vary between
2 to 4 inches,
7. After stripping, the next six inches of native soil should be scarified,
moisture conditioned as necessary, and recompacted to a minimum of 90%
relative compaction based on ASTM Test Procedure Dl557-70.
8. After the surface areas are prepared, fill, if required, shall he
placed in layers which when compacted shall not exceed six inches in
thickness. Each layer shall be compacted to 90% relative compacotion
based on the aforementioned compaction standards •
9. If any import material is to be used for fill, it should be approved
by the Soil Engineer prior to being imported to the site. If import
material should be required, it must, therefore, meet the following
recommendations:
a) Have a plasticity index of less than 10;
b) Have not more than 15% passing the No. 200 sieve;
c) Have an R-Value of not less than 25 •
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Foundations
Project No. 1273-E 27 June 1975
10. The proposed structures may be supported on continuous perimeter and
isolated interior spread footings or on friction pier and grade beam
foundation sys terns •
Perimeter Footings and Interior Spread Footings
11, A spread.footing type foundation system may be used to support the
·residential structure. These footings shall be founded a minimum of 12
inches below lowest adjacent grade and be a minimum of 12 inches wide.
12. An allowable bearing capacity for the continuous and isolated spread
footing foundations of 2, 000 p, s, f. for dead plus live loads may be used.
For the above conditions, the bearing capacity value. may be increased by
one-third to include short-term seismic and wind effects •
Pier and Grade Beam Foundation Systems
13. Concrete friction piers having a 12-::.nch minimum diameter could he
used to support the residential structure. The piers should have a minimum
depth of five feet below the lowest adjacent grade. All pier holes should
be thoroughly cleaned prior to placing the concrete. E'1ch vier should be
reinforced wi.th a minimum of two No. 4 bars for the full length and the
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Project No. 1273-E 27 June 1975
reinforcement should extend to tie into the top steel of the grade beam •
Grade beams should be founded a minimum of six inches below final exterior
grade and must be reinforced with a minimum of four No. 4 bars, two in top
and two in bottom. Provided the foregoing conditions are !\let, an allow-
able skin friction design value of 400 p.s.f. for dead plus live load may
be used for design purposes. The allowable design value may be increased
by one-third to include temporary effects of seismic and wind. loading .
No design friction value should be assigned to the upper 12 inches of
embedment •
Concrete Slabs-on-Grade
14. All concrete slabs-on-grade should be placed on a minimum of 4-inch
layer of clean course sand, clean crushed rock, or a mixture of sand and
gravel, in order to serve as a capillary break and cushion layer. Where
floor covering is anticipated, the use of a visqueen-typc barrier is
recommended to reduce moisture condensation beneath the floor covedng .
A two-~_nch layer of sand may be placed over the visqueen barrier to
facilitate the placement of concrete without damage to the barrier and to
help in the curing of the concrete. It is suggested that prior to placing
t:he concrete slabs, the subgrade soils should be presoaked until a moi.sture
equilibr:ltutn condition is reached. 'l'he concrete slabs should be rei.nforced
with a minimum of wire mesh, however, due to the difficulty of proper
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Project No. 1273-E 27 June 1975
placement of the wire mesh within the center of the slab, the equivalent
bar reinforcing is preferable,
General Construction Requirements
15. The compaction of trench backfill within .the building and parking
area should be to the same degree of compaction as the engineered fill
adjacent to the trench. No jetting of trenches should be permitted without
prior approval of the Soil Engineer •
16. The surface soils on the site possess low expansive characteristics.
Therefore, continuous roof gutters are optional. It should be noted, how-
ever, that run-off water should be dischnrged away from the house founda-
tions, lf gutters and downspouts are incorporated, splash blocks should
be used •
17. Care must be exercised in the location of all improvements so that
the natural drainage is not blocked •
18. Project plans should be reviewed by the Soil Engineer for compliance
with the recoilliilendations of this report before construction begins •
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LillITATlONS AND UNIFORMITY OF CONDITIONS
1. The recommendations of this report ure bused upon the assumption that
the soil conditions do not deviate from those \lisclosed in the borings and
from a reconnaissance of the site. If any variations er undesirable condi
tions are encountered during the development of the site, TERRASEARCH, INC.,
should be notified so that supplemental recommendations may be given •
2. This report is issued with the understanding that it is the responsibility
of the owner, or of his representative, to ensure that the information and
recommendations contained herein are brought to the attention of the Archi
t.ect and Engineer for the project and incorporated. into the plans, and that
the necessary steps are taken to see that the. Contractor and Subcontractors
carry out such recommendations in the field •
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Literature Research
Project No. 1273-E 27 June 1975
The research of literature included reference to general geologic maps of
the area, soil rnaps and geologic and soil reports issued for the development
of nearby projects. The specific references were as follows:
1. Brown, R.D., Jr., and Lee, W.11.K., "Active Faults and Preliminary
Earthquake Epicenters· (1969-1970) in the Southern. Part l'f the San Francisco
Bay Region." U.S. G. S. Misc. Field Studies Map FM-307 (HUD Basic Gontrib:.1tion
30), 1971.
2. Hall C.A., Jr. "Geology and Paleontology of the Pleasanton Area,
Alameda and Contra Costa Counties, California." Cal. University Cal. Publica-
tions in Geological Science, Vol. 34, No. 1, 1958.
3. Helley, E.J., Lajoie, K.R., and Burke, D.B. ,"Geologic Map of Late
Cenozoic Deposits, Alameda County, California." U.S.G.S. Misc. Field
Studies Map MF.429, 1972.
4. Reynolds and Associates, "Soil and Geologic Investigation, Th".ee Acre
Parcel, Southwest Corner, Foothill and Oak Lane." Project No. 426-1, August
1971.
5. Rogers, T. H. , "Gen:;.ogi~ Map of California , San Jose Sheet. n Calif-
ornia Division of Mines and Geology, 1968 .
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APPENDIX A
Site Plan
Location & Geology
Logs of Test Borings
Summary of Lab Test Results
Aerial Photo L'lneation
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Project No. 1273~E
27 June 1975
scci\e: 111• so1
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ROAD
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P~0ject No. lL/_~ .. 27 June 1975
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F'JOURE NO. - 2 LOCA'l'ION N ,-,
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LOGGED BY CM DATE DRILLED
SOIL DESCRIPTION
ELEV. 305 J,
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" ' I-' I'. Light brown Clayey SILT, hard, '" '" moist
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L. 3 - ' / /
I- - 1-2 '- 4 -I- -
I• Dark broton Clayey SILT, trace hard, slightly moist. ,,
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'- 6 - 1. '-,,
Project No. 1273-E 27 June 1975
BORING DIAMETER 6"
slightly 4. 5-1
of sand, 4. 5-
- ~ L Dark hrown CLAY, some Gravel, slightly L.. 7 - 1
• moist, medium dense. ,_
L.. 8 -
L.. 9 -
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:~vi.' ,_ .. ~ rA"
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- 10 - IY~
106
105
BORING NO. 1
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MISC. LAB
RESULTS
1. 5 04 24 '- - ~ Grey and brown mottled silty CLAY, moist, -11 - 1-31/ '' medium stiff - - I/}
-12 -- --13 - -
- -- 14 - -
Clayey SAND, moist.
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L •
L -
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L -
'- -L -
L -
Boring terminated at 16 1
*Ref. Topographic Survey by Creegan & D'Angelo
I FIGURE NO. 3 Log of Test Raring
• Project No. 1273-E
27 June .!..12.9.!..7-'"'i----------------. LOGGED BY CM DA TE DRILLED BORINO DIAMETER <" BORING NO. 2
• t,
h- 1 -,, ,, I/
• ... 2 - " " ·,, h- - 2-1 " h- 3 -
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.... 6 - 2-2 ,,, h- - , ,, , .... 7 -· - - I>.;_
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h- 9 - V•-1:.; ... - U1:,..
h- 10 - I~ i,;" . L - ")
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h- - bt-1 • .,, ~ 14 - (; f I'
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SOIL DESCRIPTION
ELEV. 305
Dark grey-brown Silty CLAY, slightly moist, very stiff
Mottled grey and brown Clayey SILT, s tif £, 111ols t
Dark brown CIAY'with Sandstone Gravel, ~lightly mu is t, ttlcdium dense
Grey and brown mottled
Some Sund lcnsc
GRAVEL, roun<lec.l, st re.am nlluvi u1n
Boring tc.rininat~<l at 20 fe.et.
"Ref. Topographic Survey by Creegan & D' Ange. lo
3. 5 101, 17
103 14
105 19
I FIGURE NO. 4 - Log of Tes L Boring
19
MISC. LAB
RESULTS
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• Hole Depth Dry No. Density
(ft.) (p.c.f.)
• 1-1 106.2
• 1~2 104.8
1-3 103.8
2-1 104.0
• 2-2 102.5
2-3 104.8
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TABLE I
Project No. 1273--E June 27. 1975
Summary of Laboratory Test Results
}!oisture Atterherg Limits Unconfined Content Liquid Plasticity Compressiv"
(% Dry wt.) Limit Ind"" Strength (%)
6.9 27,4 10
29.3
23.5
17.l
14.0
18.5
7.0
.Direct Shear Cbhesion Angl" of (p.s.f.) Internal
Friction (de~r"e2
250 32°
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• APPEllDIX B
• Geophysicists Report
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R. i3,,,t.,., Q.,,., i\LA . GEOL,QGl~"f
E"IGINEEAIN~ Gl;C('Jl..OGiST
IC: ...... ,,_.O~NIA RE.GISTRATIQN)
ALLIED Gt:OPHYS!CS
P.O. Box 5B3 .$AN .,.1¢~C:, CA. 9=.ii.1Q.1$ (40Q) ::!~0-2608
Terrasearch, Inc. 1580 North 4th Street San Jose, California
June 9, 1975
Attention: Mr. Curtis Messinger
Gentlemen:_
Project: Seismic refraction survey 1273-E
At vour r·equeti"L, a tiinqie fevc:1~t:U 1~cu1U~U l.y!Jl.! se1smfc rerract1on 11ne ~~s run a~ ~ne subject proper~y;. as placed on the cuurtesy plot plan provided.
Tt1e primary purpose was the detection, If pres.o·nt, of any fault trace crossing the parcel along the typi~al regional strike of N~-SE. No fault trace wa9 detected, as judged by the absencie of any low velocity gouge zone, abrupt changes in underground horizon elevations, or any abrupt horizontal velocity change.
Three underground v~iocity ranges were found:
v, , 200-1500 ft. per sec.
v2 3000 II 11 " V3 5800-6200 " " 11
Tho above data ls shown on the accompanying plate. The Time-Distance lower gra1h measures time In ml I 11-seconds and distance In feet per second. The upper half shows a cc~nputed profi I e section •
Thank you for the ooportunity cf conducting this study. Pl2ase call me if tncre are any qu-ostions.
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