HomeMy WebLinkAbout; Palomar Airport Business Park; Soil Investigation; 1986-06-01. - , -..
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UPDATE SOIL INVESTIGATION I !
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I FOR
PACIFIC BELL BUILDING ADDITION
PALOMAR AIRPORT BUSINESS PARK .
2175 CAMINO VlDA ROBLE
CARLSBAD, CALIFORNIA
JUNE 1986
ROBERT PRATER ASSOCIATES
Conrulfing Sod. Foundation 8 Geological Empeers
ROBERT PRATER ASSOCIATES
Consulting Soil, Foundation & Geological Engineers
Robert R. Prater. C.E. 1942-1980
Wm. David Hespeler. C.E.
June 19, 1986
218-15, 7213
MartinezIWong E. Associates, Inc.
Imperial Bank Tower
701 B Street, Suite 440 San Diego, California 92101
Attention: Mr. Robert Prendergast
Re: Update Soil Investigation
Pacific Bell Building Addition
Palomar Airport Business Park
2175 Camino Vida Roble
Carlsbad, California
Gentlemen:
In accordance with your request we have performed an update soil investigation
for the subject building addition:
results of our field investigation, laboratory tests, and engineering analysis. The soil and foundation conditions are discussed and recommendations for the
soil and foundation engineering aspects of the building addition construction are presented.
If you have any questions concerning our findings, please call.
Very truly yours,
The accompanying report presents the
10505 Roselle Slrcct, San Dicgo, California 92121 (619) 453-5605
FAX: (619) 453-7420
UPDATE SOIL INVESTIGATION
For
PACIFIC BELL BUILDING ADDITION
PALOMAR AIRPORT BUSINESS PARK 2175 Camino Vida Roble
Carlsbad, California
To
MARTINEZ, WONG & ASSOCIATES
IMPERIAL BANK TOWER
701 B Street, Suite 440
San Diego, Callfornia
June 1986
TABLE OF CONTENTS
Page No.
Letter of Transmittal
Title Page
Table of Contents
INTRODUCTION
SCOPE
SITE CONDITIONS
A. Surface
B. Subsurface
C. Groundwater
D. Seismicity
CONCLUSIONS AND RECOMMENDATIONS
A. Earthwork
1. Clearing and Stripping
2. Treatment of Existing Fills
3. Excavation 4. Subgrade Preparation
5. Low-Expansion Potential Layer
6. Material for Fill
7. Compaction
8. Slopes
9. Trench Backfill 10. Drainage
11. Construction Observation
B. Foundations
1. Footings
2. Slabs-On-Grade
3. Retaining Walls
4. Lateral Loads
Figure 1 - Site Plan
APPENDIX A - FIELD INVESTIGATION
1
Figure A-1 - Key to Exploratory Boring Logs
Exploratory Boring Logs 1 through 3
APPENDIX B - LABORATORY TESTING
Table 3-1 - Results of No. 200 Sieve Tests
Table 8-2 - Results of U.B.C. Expansion Index Tests
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2
2
2
3
3 3
4
4
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5
5
5
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6
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7 7
A-1
B-1
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UPDATE SOIL INVESTIGATION
FOR
PACIFIC BELL BUILDING ADDITION
PALOMAR AIRPORT BUSINESS PARK
2175 CAMINO VlDA ROBLE
CARL S BAD, CALI FOR N I A
INTRODUCTION
In this report we present the results of our update soil investigation for the
subject building addition at 2175 Camino Vida Roble in Carlsbad, California.
The purpose of this update soil investigation was to evaluate the soil condi-
tions at the site of the proposed addition and to provide recommendations con-
cerning the soil and foundation engineering aspects of the building addition
construction.
Our predecessor firm previously performed a foundation investigation for the
subject, property the results of which were presented in our report titled
"Foundation Investigation for PT6T 2A ESS Switching Center, Carlsbad, Califor-
nia," dated October 1974. In addition, the results of earthwork observation
and testing services for the original construction were presented in our report
dated January 31, 1975.
It is our understanding that the proposed building addition will be a one-
story, masonry block structure with interior steel columns. The maximum dead
plus live column and wall loads will be on the order of 44 kips and 2-1/2 kips
per lineal foot, respectively. Finish site grading will include a cut of up to
about 4 feet to the south of the existing building.
SCOPE
The scope of work performed in this investigation included a site reconnais-
sance, subsurface exploration, laboratory testing, engineering analysis of the
field and laboratory data, and the preparation of this report.
obtained and the analyses performed were for the purpose of providing design
and construction criteria for site earthwork, building foundations, slab-on- grade floors and retaining walls.
The data
SITE CONDITIONS
A. Surface
The site of the proposed bullding addition is presently occupied by a portion
of the existing building, a storage trailer and asphalt concrete pavements. A
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chain link fence separates a vacant parking lot to the south from the parking
area associated with the existing building.
the exception of the area south of the fence.
about 1-1/2 (horizontal) to 1 (vertical) and a maximum height of about 4 feet
is present adjacent to the fence.
thick cover of weeds.
proposed building addition area was not accessible to drill.
The site is relatively flat with
A slope with an inclination of
The vegetation along the slope contains a
During our investigation the southern portion of the
B. Subsurface
A subsurface investigation was performed using a truck-mounted, continuous-
flight auger drill to investigate and sample the subsurface soils. Three
exploratory borings were drilled on June 5, 1986 to a maximum depth of 15 feet
at the approximate locations shown on the Site Plan, Figure 1. Logs of the
borings and details regarding the field investigation are presented in Appen-
dix A. Details of the laboratory testing and the laboratory test results are
presented in Appendix B.
The materials encountered in Borings 1 and 2 consisted of 2-1/2 and 3-1/2 feet
of loose clayey sand fill soils, respectively, underlain by natural medium
dense and dense clayey sand with lenses of sandy to clayey silt and hard sandy
clay to the depths explored. The materials encountered in Boring 3 consisted
of approximately 8 inches of cement treated base underlain by natural medium
dense silty sand to a depth of 1-112 feet.
interbedded stiff to hard clayey silt and medium dense to dense clayey sand to
a depth of 6-112 feet which in turn was underlain by hard sandy clay to the
depth explored. Based on our laboratory test results and past experience with
similar materials the clayey sand fill soils and clayey natural soils possess a
medium to high potential for expansion.
The boring logs and related information depict subsurface conditions only at
the specific locations shown on the site plan and on the particular date desig-
nated on the logs. Subsurface conditions at other locations may differ from
conditions occurring at these boring locations. Also, the passage of time may
result in changes in the subsurface conditions due to environmental changes.
The silty sand was underlain by
C. Groundwater
Free groundwater was not encountered in any of the exploratory borings drilled
at the site and no surface seeps were observed.
that fluctuations in the level of groundwater may occur due to variations in
ground surface topography, subsurface stratification, rainfall, and other pos-
sible factors which may not have been evident at the time of our field investi-
gation.
It must be noted, however,
D. Seismicity
Based on a review of some available published information including the County
of San Diego Faults and Epicenters Map, there are no faults known to pass
through the site.
for earthquake damage in the vicinity of the site are within the active Elsi-
nore and San Jacinto Fault Zones located approximately 22 and 46 miles north-
east of the site, respectively.
The faults generally considered to have the most potential
The Rose Canyon Fault has been postulated
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- offshore approximately 8 miles southwest of the site.
(onshore) has offset Pleistocene age materials but no earthquake epicenter
clusters are associated with this fault system and no faults associated with the 3ose Canyon Fault Set are at present classified as active under current
accepted criteria.
Although research on earthquake prediction has greatly increased in recent
years, seismologists have not yet reached the point where they can predict
when and where an earthquake will occur. Nevertheless, on the basis of cur-
rent technology, it is reasonable to assume that the proposed building addition
will be subject to the effects of at least one moderate earthquake during its
design life. During such an earthquake, the danger from fault offset through
the site is remote, but strong ground shaking is likely to occur.
The Rose Canyon Fault
CONCLUSIONS AND RECOMMENDATIONS
From a soil engineering standpoint, it is our opinion that the site is suitable
for construction of the proposed building addition provided the conclusions and
recommendations presented in this report are incorporated into the design and
construction of the project.
The primary features of concern at the site are 11 the presence of existing
fill soils and the unknowns with regard to soil Compaction and the adequacy of
the original subgrade preparation and 2) the medium to high expansion potential
of the more clayey near-surface soils. Based on our records, the existing fill
soils were not placed under our observation.
regarding the placement and compaction of the existing fill soils can be pro- vided, we recommend that all the existing fill materials be removed and recom-
pacted.
the possibility of the proposed building addition being subject to excessive
total and differential settlements resulting from compression of any poorly
compacted portions of the existing fill or inadequately prepared subgrade. In
order to minimize possible damage to the structure resulting from swelling and
shrinkage of the clayey materials, the building addition must be supported on
footings that are extended deeper than we would normally recommend and the
building floor slabs as well as exterior slabs supported on a layer of low
expansion potential fill material.
Unless proper documentation
The purpose of the removal and recompaction work would be to preclude
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1 Detailed earthwork and foundation recommendations are presented in the follow-
I this report are contingent upon Robert Prater Associates being retained to
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ing paragraphs. The opinions, conclusions, and recommendations presented in
review the final plans and specifications as they are developed and to observe
the site earthwork and installation of foundations.
A. Earth work !
2 !
1. Clearing and Strippinq
The building addition area should be stripped of surface vegetation and cleared
of the existing asphalt pavement and cement treated base as well as any trash
I and debris that may be present at the time of construction. The cleared and i stripped materials should be disposed of off-site. The cleared cement treated
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base may be incorporated in the fills provided it is broken to meet the size
requirements in Item A.6.
2. Treatment of Existinq Filis
In order to provide suitable foundation support for the proposed building addi-
tion, we recommend that all existing fill material that remains after the
necessary site excavations have been made be removed and recompacted. The
recompaction work should consist of a) removing all existing fill material down
to firm natural ground, b) scarifying, moisture conditioning, and compacting
the exposed natural subgrade soils, and c) replacing the fill material as com-
pacted structural fill. The areal extent and depth required to remove the
fills should be determined by our representative during the excavation work
based on his examination of the soils being exposed. Any unsuitable materials
(such as oversize rubble andlor organic matter) should be selectively removed
as directed by our representative and disposed of off-site.
3. Excavation
Based on the results of the exploratory borings and our experience with simi-
lar soils, it is our opinion that the required site excavations can be accom-
plished utilizing ordinary heavy earthmoving equipment. The bidding contrac-
tors, however, should not be relieved of making their own independent evalua-
tion of the excavatability of the on-site materials prior to submitting their
bids.
4. Subgrade Preparation
After the site has been cleared, stripped, and the required excavations made,
the exposed subgrade soils in those areas to receive fill and/or building
improvements or pavements should be scarified to a depth of 8 inches, moisture I
I conditioned, and compacted to the requirements of Item A.7, "Compaction."
5. Low-Expansion Potential Layer
Because of the medium to high expansion potential of the clayey on-site materi-
als, we recommend that building floor slabs and exterior slabs-on-grade be sup-
ported on an 18-inch minimum thickness of compacted, low-expansion potential,
fill conforming to the requirements given under Item A.6, "Material for Fill." In cut areas this will require over excavation of the clayey material to a
depth of 18 inches below the finish site grades and backfilling of the excava-
tions with compacted low-expansion potential fill. The low-expansion potential
fill layer should extend a minimum of 5 feet beyond the perimeter limits of the
proposed building addition area and adjacent exterior slabs-on-grade.
6. Material for Fill
In general, all existing on-site soils with an organic content of less than 3
percent by volume are suitable for use as fill. Imported fill material should
be a low-expansion potential (UBC expansion index less than 50). granular soil
wlth a plasticity index of 12 or less.
on-site materials for use as fill should not contain rocks or lumps over 6
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In addition, both imported and existing
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inches in greatest dimension and not more than 15 percent larger than 2-112
inches.
Based on our previous work onsite, the materials present south of the existing
fence included silty sand. In general, the sandy soils from the required exca-
vations in the southern portion of the site may be suitable for use as low-ex-
pansion fill. Some imported low-expansion potential soil may, however, be required.
7. Compaction
All fill should be compacted to a minimum degree of compaction of 90 percent
based upon ASTM Test Designation D 1557-78. Fill material should be spread and compacted in uniform horizontal lifts not exceeding 8 inches in uncompacted
thickness. Before compaction begins, the fill should be brought to a water
content that will permit proper compaction by either: 1) aerating the fill if it is too wet, or 2) moistening the fill with water if it is too dry.
lift should be thoroughly mixed before compaction to ensure a uniform distribu-
tion of moisture.
Each
8. Slopes
We recommend that any required cut and fill slopes be constructed to an incli-
nation no steeper than 2 horizontal to 1 vertical. The project plans and
specifications should contain all necessary design features and construction requirements to prevent erosion of the on-site soils both during and after con-
struction.
planted with a protective ground cover.
Fill slopes should be constructed so as to assure that the recommended minimum
degree of compaction is attained out to the finished slope face. This may be accomplished by "backrolling" with a sheepsfoot roller or other suitable equip-
ment as the fill is raised. Placement of fill near the tops of slopes should
be carried out in such a manner as to assure that loose, uncompacted soils are
not sloughed over the tops and allowed to accumulate on the slope face.
Slopes and' other exposed ground surfaces should be appropriately
9. Trench Backfill
Pipeline trenches should be backfilled with compacted fill. Backfill material
should be placed in lift thicknesses appropriate to the type of compaction equipment utilized and compacted to a minimum desree of compaction of 90 per-
cent by mechanical means. In pavement areas, that portion of the trench back- fill within the pavement section should conform to the material and compaction
requirements of the adjacent pavement section.
the recommended low-expansion potential fill layer should be maintained in
utility trench backfills within the buiding and adjacent exterior slab areas.
In addition, the integrity of
10. Drainaqe
Positive surface gradients should be provided adjacent to the building addition
and roof gutters and downspouts should be installed so as to direct water away
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from foundations and slabs toward suitable discharge facilities.
surface water should not he allowed,. especially adjacent to the building addi-
tion or on pavements.
Ponding of
11. Construction Observation
Variations in soil conditions are possible and may be encountered during con-
struction. In order to permit correlation between the preliminary soil data
and the actual conditions encountered during construction and so as to assure
conformance with the plans and specifications as originally contemplated, it is
essential that we be retained to perform on-site review during the course of
construction.
All earthwork should be performed under the observation of our representative
to assure proper site preparation, selection of satisfactory fill materials,
as well as placement and compaction of the fills. Sufficient notification
prior to earthwork operations is essential to make certain that the work will
be properly observed.
6. Foundat ions
1. Foot i n qs
We recommend that the proposed building addition be supported on conventional,
individual-spread and/or continuous footing foundations bearing on undisturbed
natural soil and/or well-compacted fill material. All footings should be
founded at least 24 inches below the lowest adjacent finished grade. Footings
located adjacent to the tops of slopes should be extended sufficiently deep so
as to provide at least 8 feet of horizontal cover or 1-1/2 times the width of
the footing, whichever is greater, between the slope face and outside edge of
the footing at the footing bearing level. Footings located adjacent to utility trenches should have their bearing surfaces situated below an imaginary 1-112
to 1 plane projected upward from the bottom edge of the adjacent utility
trench.
At the recommended depths footings may be designed for allowable bearing pres-
sures of 2,500 pounds per square foot (psf) for combined dead and live loads
and 3,300 psf for all loads, including wind or seismic. The footings should,
however, have a minimum width of 12 inches. All continuous footings should
contain top and bottom reinforcement to provide structural continuity and to
permit spanning of local irregularities. In order to assure that footings are
founded on soils of sufficient load bearing capacity, it is essential that our
representative inspect the footing excavations prior to the placement of rein- forcing steel or concrete.
2. Slabs-On-Grade
Concrete slabs-on-grade may be supported directly on the layer of low-expansion
potential fill recommended in Item A.5. Slab reinforcing should be provided in
accordance with the anticipated use of and loading on the slab. As a minimum,
however, we recommend that the slabs be reinforced with 6x6-W2.9xWZ.9 welded
wire fabric to minimize hairline cracking of the slabs due to concrete
shrinkage.
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In areas where moisture-sensitive floor coverings are to be utilized and in
other areas where floor dampness would be undesirable, we recommend that con-
sideration be given to providing an impermeable membrane beneath the slabs.
The membrane should be covered with 2 inches of sand to protect it during con-
struction.
concrete.
The sand should be lightly moistened just prior to placing the
3. Retaininq Walls
Retaining walls must be designed to resist lateral earth pressures and any
additional lateral pressures caused by surcharge loads on the adjoining retained
surface. We recommend that unrestrained (cantilever) walls be designed for an
equivalent fluid pressure of 40 pounds per cubic foot (pcf). We recommend that
restrained walls be designed for an equivalent fluid pressure of 40 pcf plus an
additional uniform lateral pressure of 10H pounds per square foot where H = the
height of backfill above the top of the wall footing in feet. Wherever walls
will be subjected to surcharge loads, they should also be designed for an addi-
tional uniform lateral pressure equal to one-third the anticipated surcharge
pressure in the case of unrestrained walls and one-half the anticipated sur-
charge pressure in the case of restrained walls.
The preceding design pressures are for a level backfill condition and assume
that there is sufficient drainage behind the walls to prevent the build-up of
hydrostatic pressures from surface water infiltration.
be provided by means of weepholes with permeable material installed behind the
walls or by means 'of a system of subdrains.
Backfill placed behind the. walls should be compacted to a minimum degree of
compaction of 90 percent using light compaction equipment.
is used, the walls should be appropriately temporarily braced.
Retaining walls should be supported on footing foundations designed in accord-
ance with the recommendations presented previously under Item B. 1.. "Footings."
Lateral load resistance for the walls can be developed in accordance with the
recommendations presented under Item 8.4.. "Lateral Loads."
4. Lateral Loads
Lateral load resistance for the building addition and retaining walls supported
on footing foundations may be developed in friction between the foundation bot-
toms and the supporting subgrade. An allowable friction coefficient of .30 is
considered applicable. An additional allowable passive resistance equal to an
equivalent fluid weight of 250 pounds per cubic foot acting against the founda-
tions may be used in design provided the footings are poured neat against the adjacent undisturbed native soils andlor compacted fill materials.
Adequate drainage may
If heavy equipment
APPENDIX A
FIELD INVESTIGATION
A-1
The field investigation consisted of a surface reconnaissance and a subsurface
explo;-ati.-.n program using a truck-mounted, continuous-flight auger drill.
Three exploratory borings were drilled on June 5, 1986, at the approximate
locations shown on the Site Plan, Figure 1. The soils encountered in the
borings were continuously logged in the field by our representative and
described in accordance with the Unified Soil Classification System (ASTM D
2487). included as part of this appendix. The boring locations shown on the site plan
were estimated from an undated plot plan titled "Building Addition, Dalomar
Airport Business Park, 2175 Camino Vida Roble, Carlsbad, California," prepared
by MartinezlWong E Associates, Inc.
Representative samples were obtained from the exploratory borings at selected
depths appropriate to the investigation. All samples were returned to our
laboratory for evaluation and testing. Standard penetration resistance blow
counts were obtained by driving a 2-inch O.D. split spoon sampler with a 140-pound hammer dropping through a 30-inch free fall. The sampler was driven a maximum of 18 inches and the number of blows recorded for each 6-inch
interval. The blows per foot recorded on the boring logs represent the accumu- lated number of blows that were required to drive the last 12 inches or portion
thereof. Samples contained in liners were recovered by driving a 2.5-inch I.D.
California sampler 18 inches into the soil using a 140-pound hammer. Boring
log notations for the standard split spoon and California samplers as well as
for jar and sack samples taken from auger cuttings are indicated below.
Logs of the borings as well as a key for soil classification are
Standard Split Spoon Sampler a California Sampler
WX" Indicates jar sample taken
from auger cuttings.
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The boring logs show our interpretation of the subsurface conditions on the
date and at the locations indicated, and it is not warranted that they are
representative of subsurface conditions at other locations and times.
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I GRAVELS
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PRIMARY DIVISIONS
CLEAN
GRAVELS
(LESS THAN 5% FINES) MORE THAN HALF
OF COARSE
FRACTION IS
Y
SECONDARY DIVISIONS GROUP
SYMBOL
GW
GP
Well graded gravels, gravel-sand mixtures. I#ttle or no
Poorly graded gravels or gravel-sand mixtures. little or
fines
no fmes.
GRAVEL
WITH
FINES
LARGER THAN z &Qv) NO. 4 SIEVE
GM
GC
Silly gravels. gravel-sand-sill mixtures. non-plastic fines.
I Clavev aravels aravel-sand-clav mixtures. Dlastic fines.
w ZiZ g $2 +-5 $u v cc* - 0- L NO. 4 SIEVE
MORE THAN HALF
OF COARSE
FRACTION IS
SMALLER THAN
SILTS AND CLAYS
LIQUID LIMIT IS
LESS THAN 50%
Well graded sands, gravelly sands. little or no fines. CLEAN
SANDS
(EFI%? 11 Poorly graded sands or gravelly sands, little or no fines.
SANDS
WITH
FINES
Silty sands, sand-silt mixtures. non-plastic fines,
Clayey sands, sand-clay mixtures. plastic fines.
ML
c L
OL
lnor anic silts and very fine sands. rock Hour. si1t.y. or cyayey fine sands or clayey silts with slight plasticity.
lnor anic clays of low to medium plasticity. gravelly cks. sandy clays. silty clays. lean clays.
Organic silts and organic silty clays of low plasticity.
0 ,,, a: Oaz
>>I +
.
MH Inorganic sjlts, micaceous OT diatomaceous fine sandy or SILTS AND CLAYS silty soils. elastic sflts.
LIOUID LIMIT IS CH Inorganic clays of high plasticity. fat clays.
OH Organic clays of medium to high plasticity. organic silts. GREATER THAN 50%
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DEFlNITlON OF TERMS
HIGHLY ORGANIC SOILS
U.S. STANDARD SERIES SIEVE CLEAR SOUARE SIEVE OPENINGS
200 40 10 4 3/41' 3" 12"
Pt Peat and other highly organic soils.
I I COBBLES BOULDER: I SAND GRAVEL . SILTS AND CLAYS FINE MEDIUM I COARSE I FINE 1 COARSE
VERY LOOSE
LOOSE
oMEDIUM DENSE
DENSE
VERY DENSE
BLOWS/FOOT' SANDS.GRAVELS AND
NON-PLASTIC SILTS
0- 4
4 -10
10 -30
30 -50
OVER 50
0 - 1/4
1/4 - 1R
Ih-1
1-2
2-4
OVER 4
GRAIN SIZES
0-2
2-4
4-8
8 -16
16 -32
OVER 32
CLAYS AND
PLASTIC SILTS
VERY SOFT
SOFT
FIRM
STIFF
VERY STIFF
HARD
ROBERT PRATER ASSOCIATES
Conivlliop SOL Fouodomn 6 Geologrcol Enpineerr
PACIFIC BELL BUILDING ADDITION
Carlsbad, California
PROJECT NO. DATE I Figure A-1 21 8-1 5 June 1986
RELATIVE DENSITY CONSISTENCY
'Number of bkws of 140 mnd hammer falling 30 inches to drive a 2 inch 0.0 0-3/8 inch I.D.)
split spoon (ASTM D-1586).
%Lhconfined cmpressive strength in tons/sq. fi. as determined by laboratory testing cf approximated
@ lhe standard penetration test (ASTM D-1586). pocket penetrometer, torvane. OT visual observation.
DESCRIPTION AND CLASSIFICATION I
DEPTH TO GROUNDWATER None BORING DIAMETER 6
-
SOIL WPE
/-
sc
SCI- ML-
--
3L
21 Inches ASPHALT CONCRETE 3 Inches CLASS II BASE
inches DATE DRILLED
E DEPTH ii
(FEET) 5
ul
- -
1- - -_ - 2- - - - 3 -- - - - - __ - 5 - -
-6- - __
-7- - -
8 - - -
-9- - - - 10 -- - -
- 11 - - -_ - 12 -x - - - 13 - - - - 14 - - -
--5 -=
r -
I(Some gravel between + - 1
I
$" FILL 1
LAYEY SAND with lenses of
PROJECT NO. DATE BORING NO. 1 218-15 I June 1986
FANDY-CLAYEY SILT
ANDY CLAY
Ittom of Boring = 15 Feet
Note The ~lratili~ation lines represent the appro~imale
bundary between rnaterlai types aid the transition may
be gradual.
ROBERT PRATER ASSOCIATES
Conrvllmp Sod Fovndoaoii d Geoloptcol Enpmeem
COLOR
lrayisl
brown-
,ed d i s I
brown
,eddisl
brown
-
>live
I'aY
CONSIST.
--
loose
-- medium
dense
--
hard
EXPLORATORY BORING LOG
PACIFIC BELL BUILDING ADDITION
Carlsbad, California
ROBERT PRATER ASSOCIATES
iontulimp Sod foundohon d Geolop~col Enpfneerc
EXPLORATORY BORING LOG
PACIFIC BELL BUILDING ADDITION
Carlsbad, California
3
PRGJECTNO. I DATE
218-15 I June 1986
BORING NO.
LOGGEDBY JB DRILLRIG Continuous Flight Auger SURFACEELEVATION ---
DEPTHTOGROUNDWATER N~~~ BORING DIAMETER 6 Inches DATE DRILLED
I I
I PROJECT NO. DATE
218-15 I June 1986
DESCRIPTION AND CLASSIFICATION
3 BORING
NO.
DESCRIPTION AND REMARKS
ZEMENT TREATED BASE
SILTY SAND
;ANDY-CLAYEY SILT and
ZLAYEY SAND
;ANDY CLAY
lottom of Boring = 10 Feet
Note: The slralificalion lines represent the approwwr
bOundaw between rnaletial lypes aid the lran5i11on may
be gradual.
COLOR -
dense
dense
EXPLORATORY BOR(NG LOG
PACIFIC BELL BUILDING ADDITION
6-1
APPENDIX B
LABORATORY TESTING
Thc natural mater content was detertzined on selected samples and is recorded on
the horing logs at the appropriate sample depths.
Five No. 200 sieve tests were performed on selected samples of the subsurface
soils to aid in classifying the soils according to the Unified Soil
Classification System. The results of these tests are presented in Table B-1.
One laboratory expansion test was performed on a representative sample of the
more clayey near surface soils encountered in the exploratory borings.
test was performed in accordance with the Uniform Building Code Standard No.
29-2.
The
The results of the test are presented in Table 6-2.
Exploratory
Borinq No.
1
1
2
2
3
218-15
TABLE B-1
RESULTS OF NO. 200 SIEVE TESTS
Sample Depth
(Feet
2
4
1/2 - 3
4
2
Percent Passing
Sample Description No. 200 Sieve
CLAYEY SAND (SC) 45
SANDY SILT (MLI 52
CLAYEY SAND (SC) 48
CLAYEY SAND (SC) 40
SANDY SILT (ML) 62
TABLE B-2
RESULTS OF U.B.C. EXPANSION INDEX TESTS
Molding Initial
Sample Moisture Dry Exploratory Depth Content Density Expansion
Borinq No. (Feet) Soil Type (%I (pcf) Index
2 112 - 3 CLAYEY SAND 9.4 108.7 91
(SC)
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