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`-; Report of Geotechnical Engineering
Services .
Proposed Tigard Triangle Development
'° . Tigard, Oregon I
. ' May 4, 1998
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For
J ` Specht Development
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G e o E n g i n e e r s File • No. 4217 -013-00 -2130
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■
1 . Geode Engineers
Consulting Engineers
and Geoscientists
.=-7 May 4, 1998 Offices in Washington,
Oregon, and Alaska
.
1 Specht Development
15400 Southwest Millikan Way
l Beaverton, Oregon 97006
Attention: Mr. Todd R. Sheaffer
1 GeoEngineers is pleased to submit five copies of our "Report of Geotechnical Engineering
Services, Proposed Tigard Triangle Development, Tigard, Oregon." The site is comprised of
`j approximately 6 acres and is located between Southwest 69th Avenue and the alignment for
Southwest 70th Avenue, from Southwest Dartmouth Street to Southwest Beveland Street. Our
services were conducted in accordance with our April 3, 1998 proposal.
:1 We appreciate the opportunity to be of service to Specht Development. Please call if you
have questions regarding this report.
Respectfully Submitted,
r
GeoEngineers, Inc.
r
Marcella M. ler, P.
Project Engin
:..2 C D 9 .4,. '7Z.,
,.,
David L. Thielen, P.E.
LIL Associate
•
MMB:DLT:min
Document ID: 4217013rgeo.doc
File No. 4217 -013-00
7 cc: MR. Jim Knauf
VLMK Consulting Engineers
( l:
GeoEngineers, Inc.
7504 SW Bridgeport Road
d Portland, OR 97224
Telephone (503) 624 -9274
3 Fax (503) 620-5940 — -_-- — - -- -- - -_ - - -
I; , i
i ..
i ` CONTENTS
1 Page No.
I INTRODUCTION 1
PURPOSE AND SCOPE 1
.I SITE CONDITIONS 2
SURFACE CONDITIONS 2
SUBSURFACE CONDITIONS 3
b: CONCLUSIONS AND RECOMMENDATIONS 4
GENERAL 4
9 SITE PREPARATION 5
CONSTRUCTION CONSIDERATIONS 6
BOULDER EXCAVATION 7
T STRUCTURAL FILL 7
AREAL SETTLEMENT FROM FILL PLACEMENT 8
UTILITY TRENCH EXCAVATION AND DEWATERING 9
DRAINAGE CONSIDERATIONS 10
PERMANENT SLOPES 10
SHALLOW FOUNDATIONS 10
ri RETAINING STRUCTURES 11
RESISTANCE TO SLIDING 12
SLAB -ON -GRADE 12
SOIL CORROSIVITY 13
Li PAVEMENT 13
SEISMIC CONSIDERATIONS 14
OBSERVATION OF CONSTRUCTION 15
LIMITATIONS 15
=B
°° FIGURE Figure No.
3 V icinity Map 1
Site Plan 2
Lateral Earth Pressures - Temporary Shoring 3
Schematic of Recommended Subsurface Dram 4
1
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G e o E n g i n e e r s i File No. 4217-013-00-2130/050498
CONTENTS (continued)
APPENDICES Page No.
Appendix A - Field Explorations and Laboratory Testing A -1
Field Explorations A -1
Laboratory Testing A -1
1
APPENDIX A FIGURES Figure No.
Soil Classification System A -1
L. Key to Test Pit Log Symbols A -2
Log of Test Pits A -3 ... A -21
1 Consolidation Test Results A -22
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EJ
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G e o E n g i n e e r s 11 File No. 4217 -013-00 - 2130/050498
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1 '
't I REPORT OF GEOTECHNICAL ENGINEERING SERVICES
PROPOSED TIGARD TRIANGLE DEVELOPMENT
`0 TIGARD, OREGON
i FOR
SPECHT DEVELOPMENT
f
INTRODUCTION
' This report presents the results of GeoEngineers' geotechnical engineering evaluation of the
proposed development in Tigard, Oregon. The approximate 6 -acre site is located between
Southwest 69th Avenue and the alignment for Southwest 70th Avenue and between Southwest
L i Dartmouth Street to Southwest Beveland Street. The site location relative to surrounding
physical features is shown in Figure 1.
Building size, locations and grading plans are preliminary. We were informed that
n development of the site will include constructing three two -story or two three -story office
buildings, as well as associated asphalt paved parking areas and underground utilities. We have
included the three building layout in Figure 2. Two buildings will be approximately
t:.
40,000-square-foot in size (Building A and Building B) and one building will be approximately
35,000- square -foot in size (Building C). The column loads for the structures is anticipated to
be less than 250 kips, continuous wall footing loads will be less than 4 kips per foot, and floor
slab oads f are anticipated to be less than 250 pounds per square foot (pst). Approximate
i
' -foot cu could occur at this site. The proposed maximum fill thickness for this site is
12 feet.
el PURPOSE AND SCOPE
e purpose of our geotechnical services is to explore subsurface and ground water
conditions at the site and provide geotechnical engineering recommendations for site
Li development and foundation design. Our specific scope of services is summarized as follows:
1. Explore subsurface conditions by excavating a total of 19 test pits to a maximum depth of
^' 19 feet.
2. Obtain soil samples at selected intervals.
3. Classify the material encountered in the test pits in general accordance with American
Society for Testing and Materials (ASTM) D 2488. Maintain a detailed log of each
exploration.
1 4. Observe ground water conditions in the test pit excavations.
5. Complete laboratory analyses on soil samples obtained from the explorations to determine
7
moisture content, dry density, and compressibility in general accordance with test methods
ASTM D 2216, ASTM D 2937 and ASTM D 2435, respectively.
6. Provide laboratory test results of soil corrosivity tests.
3
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- 4 1 7. Provide recommendations for site preparation, grading and drainage, stripping depths, fill
type for imported materials, compaction criteria, temporary and permanent cut and fill
7 slope criteria, trench excavation and backfill, use of on -site soils, and wet and dry weather
earthwork.
8. Provide recommendations for design and construction of shallow spread foundations,
including allowable design bearing pressure and minimum footing depth and width.
9. Estimate settlement of footings and floor slabs under design loadings.
10. Provide recommendations for the design and construction of floor slabs, including an
anticipated value for subgrade modulus and capillary break information.
11. Provide design criteria for retaining walls including lateral earth pressure, allowable
bearing pressure for retaining wall footings, backfill compaction and drainage.
12. Provide passive earth pressures and coefficient of friction.
t 13. Provide recommendations for construction of asphalt- concrete pavements for on -site access
roads and parking areas, including subgrade, base rock and asphalt paving thicknesses.
14. Provide recommendations for subsurface drainage of floor slabs and foundations.
15. Provide recommendations for temporary excavations and dewatering of trenches.
16. Provide seismic design criteria, including peak ground accelerations (PGAs) for a
,- maximum credible and a maximum probable earthquake, recommendations for the Uniform
J Building Code (UBC) site coefficient and seismic zone, and a discussion on the liquefaction
potential at the site.
17. Present our findings, conclusions and recommendations, together with supporting field and
laboratory information, in a written report.
` i SITE CONDITIONS
SURFACE CONDITIONS
The site is located between Southwest 69th Avenue and the alignment of Southwest
70th Avenue and between Southwest Dartmouth Street and Southwest Beveland Street. The
topography of the site slopes generally downward toward the west, with the steepest slope
.7-1 adjacent to Southwest 69th Avenue near Southwest Dartmouth Street.
The site is heavily wooded with relatively thick undergrowth. The ground surface is
: uneven and has small hills and swales. A seasonal stream bed, which was dry at the time of
our explorations, runs along the north edge of the property. A stream bed, active at the time of
our exploration, runs east to west across the site near the south edge of the proposed
Building B. Some ponded water was observed in low areas in the northwest portion of the site.
c. Vacant houses are located in the northeast and southwest corners of the property. e We also
^
1 observed two small houses in the southwest portion of the site. These structures appeared to
have been abandoned for a long time. Additionally, we observed two concrete house
foundations without structures between the proposed locations for Buildings A and B.
>'' A wide variety of household garbage, tires and landscape debris was observed scattered
0 across the site and in stockpiles in some locations. We observed several small piles of garbage
that included household items, glass, brick and metal. The largest garbage pile is located east
G e o E n g i n e e r s 2 File No. 4217 -013-00- 2130/050498
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^! of the proposed Building C and encompasses an area approximately 20 to 25 feet in diameter.
The presence of the garbage suggests that this area has been used in the past for disposal. Old
automobile tires were observed in small piles and scattered at isolated locations across the site.
1..1
SUBSURFACE CONDITIONS
Introduction
Subsurface conditions at the site were explored by excavating 19 test pits, TP -1 through
1 TP -19, to depths between 4 and 19 feet below current ground elevation at the approximate
locations shown in Figure 2. Selected soil samples from the test pit excavations were tested to
determine the natural moisture content, density (unit weight), compressibility and corrosivity
1 characteristics. A description of the field exploration and laboratory testing programs are
included in Appendix A. The test pit logs and laboratory test results are also included in
Appendix A.
General
Generally, subsurface conditions consist of silt underlain by boulders in a silt matrix. We
observed an exception to this profile in test pit TP -18, which was excavated near an existing
- drainage ditch. We observed an approximate 6- inch -thick layer of medium dense silty gravel
approximately 3 feet below the ground surface. The gravel layer is located within the silt unit.
We observed an approximate 6- to 18- inch -thick root zone at the surface of the site, with
the exception of test pits TP -1 and TP -18. In these test pits, we observed approximately 1 foot
of loose silty gravel fill at the surface.
Silt
We observed silt with varying amounts of sand and clay that extended to a maximum depth
i l of 3.5 and 18.5 feet. The silt was generally medium stiff to very stiff, however, we observed
- soft silt at isolated locations near the surface of the site in test pits TP -3, TP -8, TP -9, TP -12,
TP -13, TP -15, TP -16 and TP -18.
J In test pit TP -18, we observed soft to medium stiff silt between 1 and 3 feet and between
"` 3.5 and 6.0 feet. A 6- inch -thick gravel layer separates the silt layers. We also observed minor
: :, caving of the walls of test pit TP -18 in the upper 4 to 5 feet of the test pit.
The moisture content of the silt varies between 22 and 33 percent and the dry density is
between 87 and 96 pounds per cubic foot (pcf). The material has a relatively high
,g preconsolidation pressure with low to moderate compressibility.
Boulders
a Boulders were encountered in all of the test pits, except test pits TP -2, TP -5, TP -12,
TP -13, TP -14 and TP -15. The boulders were generally observed at depths between 11.0 and
. 18.5 feet. However, boulders were encountered at 7.5 feet in test pit TP -8 and at 3.5 feet in
Lei TP -9. A stream bed is located in the vicinity of these two test pits.
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The boulders are bedded in a silt matrix, which is similar to the overlying silt, and are
closely spaced. Generally, we met refusal between 6 and 12 inches into the boulder layer. In a
few of the test pits, we were able to excavate around the boulders. We removed boulders as
small as 1 foot in diameter from the test pits. We were unable to determine the maximum
diameter because we could not remove the boulders from the test pits, but speculate that it is
larger than 3 feet.
Ground Water
• Slow ground water seepage was observed in test pits TP -1, TP -2, TP -8, TP -13, and TP -18
l _ at depths between 2 feet and 17 feet below the ground surface. Typically, the seepage occurred
from 1 foot thick or smaller zones on the test pit walls and likely represents water that is
perched on less permeable soil layers. Seepage was not observed in the remainder of the test
pit excavations.
We left test pits TP -1 and TP -2 open approximately 5 hours. Significant water did not
accumulate in test pit TP -1. Approximately 12 inches of water accumulated in the base of test
pit TP -2. The depth of ground water could vary due to rainfall, irrigation, changes in surface
topography or other factors not observed during our site investigation.
CONCLUSIONS AND RECOMMENDATIONS
GENERAL
Based on the results of our subsurface exploration and analysis, the subsurface conditions
`- are suitable to provide support of the proposed development. Fills up to 12 feet and up to
10- foot -thick cuts are planned in portions of the site. Based on our analyses, areal settlement
from 12 feet of fill will be approximately 2 inches. We recommend allowing the fills thicker ' a
than 4 feet to settle prior to proceeding with construction of site structures. t/►+
The structures can be supported on shallow foundations founded on the medium stiff to
very stiff silt, boulders or on structural fill underlain by firm material. We observed soft silt at
isolated locations at the site as described in the previous section of this report. The soft silt is
not suitable for support of the building floor slabs, spread foundations or pavements. This
material should either be (1) removed and replaced as compacted structural fill, (2) scarified
and compacted in place as structural fill if the material is less than approximately 12 inches
thick or (3) treated with cement amendment and compacted.
We encountered boulders in the majority of the test pit excavations. Based on the proposed
grading plan, the boulders are likely below the excavation depths of buildings. However,
boulders may be encountered during footing excavations in cut areas and during installation of
the underground utilities, depending on the invert elevation of the utilities. Our excavations
indicated that considerable effort was required to excavate more than 1 foot into the boulder
layer. However, the excavations planned during construction will likely be larger than our test
ty" pits and may be able to achieve greater penetration into the boulders.
Relatively shallow ground water seepage was observed in the test pit excavations at both
sites. Ground water seepage could be encountered during construction of the project at depths
i t G e o E n g i n e e r s 4 File No. 4217 -013 -00- 2130/050498
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varying from those observed in the test pit excavations. Temporary dewatering may be
required in trench excavations. Additionally, permanent subsurface drainage may be required
for this project in cut areas.
The following paragraphs present specific geotechnical recommendations for design and
1 construction of the proposed development at both sites.
SITE PREPARATION
9 We understand that the site will be logged prior to beginning earthwork activities to remove
the trees designated for removal. The trees, brush and forest litter should be removed from the
proposed building and paving areas. The tree and brush root balls should be grubbed out to
0 remove the roots. Soil that is disturbed or loosened during grubbing activities should be
excavated to expose firm soil and backfilled with structural fill. If the depth of disturbance is
limited to less than 12 inches, the surficial materials can be scarified and recompacted in place.
We recommend demolishing existing structures, foundations, concrete pads and other
buried features that are located within the proposed building and pavement areas. These 1 4
w� structures should be demolished and the debris disposed of off site. Based on the presence of
existing structures, it is likely that other remnants of previous construction are located on the
site. A contingency in the project budget is appropriate to cover unknown buried site features.
The existing garbage, debris and tires should also be removed and transported off site for
disposal.
The concrete from the slabs and footings can be broken up into small, less than 6 -inch-
diameter particles, mixed thoroughly with structural fill material and used to fill low areas of
the site. However, we do not recommend using broken concrete beneath buildings or within
j 3 feet of final pavement elevation. The concrete should be disposed of off site if the debris
cannot be used for site filling.
We recommend removing the existing root zone from the site in all of the building and
pavement areas. Removal should extend at least 5 feet beyond these areas. Stripping depth
will likely vary between 6 and 18 inches; however, greater stripping depths and localized
LI
overexcavation may be required to remove zones of soft or organic soil. The actual stripping
depths should be determined based on field observations at the time of construction. Stripped
materials should be transported off site for disposal or used for landscaping purposes.
'.' , We observed soft silt at isolated locations at the site as described in the previous section of
this report. The soft silt is not suitable for support of the building floor slabs, spread
foundations or pavements. This material should either be (1) removed and replaced as
compacted structural fill, (2) scarified and compacted in place as structural fill if the material is
less than approximately 12 inches thick or (3) treated with cement amendment and compacted.
Based on our excavations, the thickness of the soft soil typically extends 1 to 2 feet below the
root zone.
i` After site preparation activities and site cuts have been completed, we recommend
wt;
proofrolling the subgrade with a fully loaded dump truck or similar- sized, rubber -tire
construction equipment to identify areas of excessive yielding. The proofrolling should be
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i G e o E n g i n e e r s 5 File No. 4217 -013-00- 2130/050498
observed by one of our geotechnical engineers, who will evaluate the subgrade. If areas of
excessive yielding are identified, the material should be (1) excavated and replaced with
a compacted materials recommended for structural fill (2) scarified, moisture conditioned and
' recompacted or (3) treated with cement amendment.
The test pit excavations were backfilled using the relatively minimal compactive effort of
the backhoe bucket. Therefore, soft spots can be expected at these locations. Additionally, our
test pit exploration locations were determined based on a building layout provided by Specht
Development in their request for proposal dated March 26, 1998. The proposed building layout
in Figure 2 is different from the original layout and has resulted in test pits excavated within
some building footprints. We recommend that these relatively uncompacted soils be removed
1,:l from the test pits located within the proposed building and paved areas to a depth of 3 feet
below finished subgrade. The resulting excavation should be brought back to grade with
structural fill.
CONSTRUCTION CONSIDERATIONS
Trafficability of the soils at the sites will be difficult during periods of rainfall or when the
moisture content of the surficial soil is more than a few percentage points above optimum
;-� moisture content. When wet, this material is susceptible to disturbance and will provide
inadequate support for construction equipment. The soft silt that was observed in test pit TP -18
is especially susceptible to disturbance if exposed during wet conditions.
'` If construction occurs during the wet season, we recommend that site preparation activities
j be accomplished using track- mounted equipment. The poor trafficability of the native materials
j may require stripping operations to be done progressively across the site, loading removed
material into trucks supported on granular haul roads. The subgrade should be evaluated by a
qualified geotechnical engineer by probing with a steel rod, rather than by proofrolling. Wet
g soil that has been disturbed during site preparation activities, or soft or loose zones identified
during probing, should be removed and replaced with structural fill.
The use of granular haul roads or staging areas will be necessary for support of
7 construction traffic during the rainy season or if the ground surface remains wet. A 12 -inch
thickness of imported granular material generally should be sufficient for light staging areas and
the basic building pad but is generally not expected to be adequate to support heavy equipment
or truck traffic. Haul roads and areas with repeated heavy construction traffic should be
constructed with a minimum thickness of 18 inches of imported granular material. We
recommend that a geotextile be placed as a barrier between the subgrade and imported fill in
1 areas of repeated construction traffic. The geotextile should have a minimum Mullen burst
strength of 250 pounds per square inch (psi) for puncture resistance and a minimum apparent
opening size (AOS) of a U.S. Standard No. 70 Sieve to minimize migration of fines into the
imii
rock.
j'''. Imported granular material used for haul roads and staging areas should consist of crushed
rock that is well - graded between coarse and fine sizes, contain no organic matter or unsuitable
materials, no particles larger than 3 inches, and have less than 5 percent by weight passing the
gi
2 G e o E n g i n e e r s 6 File No. 4217 -013 -00- 2130/050498
1 U.S. Standard No. 200 Sieve. The imported granular material should be placed in one lift over
the prepared undisturbed subgrade and compacted using a smooth drum, roller without the use
.. i of vibratory techniques.
:.l
BOULDER EXCAVATION
We encountered boulders in the majority of the test pit excavations at depths below 11 and
19 feet and at shallower depths of 7.5 and 3.5 feet in test pits TP -8 and TP -9, respectively.
Based on the proposed grading plan and the results of our test pit explorations, boulders could
be encountered during excavation in cut areas and in utility trench excavations if the invert
elevation is deeper than the boulders. Some boulder excavation and processing will likely be
r required.
1i
A John Deere 490 track - mounted backhoe was able to excavate into the underlying boulders
f: less than 1 foot. Greater excavation depths may be possible during site excavation with larger
equipment excavating over a larger area. An alternate method of removing the boulders would
,1
be to break the material in place using a hydraulic hammer attached to a backhoe.
STRUCTURAL FILL
./ On -site Silt
Li The on -site silt can be used as structural fill if the material is free of organic matter and
other deleterious materials and particles larger than 3 inches in diameter. Use of the on -site silt
as structural fill may be difficult because these materials can be sensitive to small changes in
moisture content and are difficult, if not impossible, to adequately compact during wet weather
or when the material is just a few percentage points above optimum. Laboratory testing
indicates that the moisture content of the on -site materials is greater than the anticipated
optimum moisture content required for satisfactory compaction. Therefore, moisture
I. conditioning will be required to achieve adequate compaction. We recommend using imported
a granular material for structural fill if the silt cannot be properly moisture - conditioned.
When used as structural fill, the on -site materials should be placed in lifts with a maximum
uncompacted thickness of 6 to 8 inches and be compacted to not less than 95 percent of the
t
maximum dry density, as determined by ASTM D 1557.
An experienced contractor may be able to amend the on -site silt with lime or cement to
Li obtain suitable support properties. The percentage by weight of lime or cement depends on the
moisture content of the soil being amended, and usually varies between 3 and 5 percent. Soil
; . amendment is most effective if the moisture content of the soil is less than 40 percent.
GeoEngineers should be retained to evaluate the proposed amendment procedures if soil
amendment is used during construction.
Boulders
i
Boulders encountered during development could be processed into particles smaller than
6 inches and used for structural fill, provided the processed material is blended with enough soil
to fill the voids. The blended material can be used for structural fill in utility trenches and
[a;
GeoEngineers 7 File No. 4217 -013-00- 2130/050498
parking areas at elevations greater than 3 feet below the finish subgrade elevation. This
material should be placed in a maximum uncompacted lift thickness of 12 inches and compacted
to not less than 95 percent of ASTM D 1557 or equivalent standard determined by
GeoEngineers.
Imported Granular Material
Imported granular material should be used as structural fill during wet weather or if the
- on -site materials cannot be properly moisture - conditioned. Structural fill should be pit or
1 quarry run rock, crushed rock, or crushed gravel and sand that is fairly well - graded between
coarse and fine, contain no organic matter and other deleterious materials, have a maximum
Li particle size of 3 inches, and have less than 5 percent passing the U.S. Standard No. 200 Sieve.
The percentage of fines can be increased to 12 percent of the material passing the U.S.
f - Standard No. 200 Sieve if placed during dry weather and provided the fill material is moisture -
_ conditioned, as necessary, for proper compaction.
The material should be placed in lifts with a maximum uncompacted thickness of 12 inches
and compacted to not less than 95 percent of the maximum dry density, as determined by
ASTM D 1557. During the wet season or when wet subgrade conditions exist, the initial lift
I should have a maximum thickness of 15 inches and should be compacted using a smooth drum
;; roller without the use of the drum vibrator.
Trench Backfill Material
Trench backfill for the utility pipe base and pipe zone should consist of well - graded
' granular material with a maximum particle size of 3/4 inch and less than 5 percent passing the
ice
U.S. Standard No. 200 Sieve. The material should be free of organic matter and other
deleterious materials. Backfill for the pipe base and pipe zone should be compacted to at least
"" 90 percent of the maximum dry density, as determined by ASTM D 1557 or as recommended
by the pipe manufacturer. Within building and pavement areas, trench backfill placed above
the pipe zone should be compacted to at least 92 percent of ASTM D 1557 at depths greater
,: than 2 feet below the finished subgrade and as recommended for structural fill within 2 feet of
j finished subgrade. In other areas, trench backfill above the pipe zone should be , compacted to
90 percent as determined by ASTM D 1557.
t L
Lis
AREAL,SETTLEMENTFROM FILL PLACEMENT
1 ills up to 12 feet are planned for site developme . Basedon our analyses, total settlement
f from 12 feet, of fill will be on the order of 2 inches. a anticipate that the majority of the
7,1 within 3 to 4 weeks after fill placement. We recommend reducing
postconstruction settlement by modifying the construction schedule to allow the filled areas to
settle prior to constructing site structures. As an alternate, postconstruction settlement could be
reduced by placing a surcharge within the fill areas of the building. We estimate that a 4 -foot
I surcharge will reduce the time required for primary consolidation to approximately 2 weeks.
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GeoEngineers 8 File No. 4217 -013-00- 2130/050498
.
Settlement should be monitored with at least four indicators installed at select locations in
1 each fill area. The indicators should be steel bars driven a minimum of 24 inches into the fill.
"? The indicators should be monitored using survey equipment with an accuracy of 1 /100th of a
-j foot. The first survey reading should be obtained immediately following placement of the fill.
Survey shots should be taken at each settlement indicator at least twice weekly following
placement of the fill and should be provided to our office for review. The settlement data
should be reviewed by a geotechnical engineer with GeoEngineers, who will determine when
- - 1 primary consolidation is complete and when construction of the building can begin.
.1
UTILITY TRENCH EXCAVATION AND DEWATERING
71 Ground water seepage was observed between approximate depths of 2 and 17 feet below the
L.1
ground surface and likely represents perched or locally concentrated ground water. Our
... explorations were conducted at the end of the rainy season when near - surface water seepage are
i generally more persistent. The ground water levels may drop in response to dry weather;
however, we anticipate that some form of dewatering may be required to maintain dry working
1 conditions if the invert elevations of the proposed utilities are below the ground water level or if
perched water conditions are present.
If ground water is present at the base of the excavation, we recommend placing 1 foot of
trench stabilization material at the base of the excavation. Trench stabilization material should
°_ consist of well-graded gravel, crushed gravel or crushed rock with a minimum particle size of
4 inches and less than 5 percent passing the U.S. Standard No. 4 Sieve. The material should be
free of organic matter and other deleterious material. Trench stabilization material should be
placed in one lift and compacted.
Trench excavations should be made in accordance with applicable Occupational Safety and
i- Health Administration (OSHA) and state regulations. The contractor should have the
responsibility of selecting trench dewatering and excavation methods, monitoring the trench
excavations for safety, and providing shoring as required to protect personnel and adjacent
improvements.
3 Temporary cuts into the silty materials are expected to be stable with vertical cuts with
excavation depths up to 4 feet provided ground water seepage is not present. We recommend
that cuts extending deeper than 4 feet or in areas where ground water seepage is present either
be cut flatter or shored.
Temporary shoring or trench boxes may be necessary to support the trench walls in areas
A • where the lateral extent of the excavation must be limited. Shoring design should be prepared
by an experienced professional engineer and can be based on the lateral earth pressures shown
in Figure 3. Increased lateral pressures resulting from surcharge loads from equipment,
stockpiled material or construction activities should be considered in the design of the shoring
ult system.
rf
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3 i G e oE n g i n e e r s
9 File No. 4217 -013 -00- 2130/050
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DRAINAGE CONSIDERATIONS
Surface Drainage
A We recommend that all roof drains and subsurface drains be connected to a tightline leading
to the storm drain. Pavement surfaces and open space areas should be sloped such that the
surface water runoff is collected and routed to suitable discharge points. We recommend that
j the ground and paved surfaces adjacent to the building be sloped to drain away from the
buildings.
r 1
Subsurface Drainage
Shallow ground water seepage may be encountered during site preparation activities,
depending on final construction grades and the time of year that construction occurs.
Depending on the amount and persistence of ground water seepage encountered during the site
preparation, subsurface drains may need to be installed in cut areas around the perimeter of the
buildings, and for the proposed parking lot and access roads. The subsurface drains should be
designed to lower the ground water below the level of the building floor slab or pavement base
rock. We should be retained to review the grading plan to provide recommendations for the
location of permanent subsurface drainage if required. Additional permanent drainage may
need to be installed during site preparation activities if required. Figure 4 shows a typical
schematic of a subsurface drain.
PERMANENT SLOPES
Permanent slopes should not exceed 2 horizontall1 vertical (2H:1V). Footings, buildings,
access roads and pavements should be located at least 5 feet horizontally from the slope face.
Fill slopes should be overbuilt by approximately 2 feet and cut back to grade so that the slope
face is compacted. The slopes should be planted with appropriate vegetation to provide
protection against erosion as soon as possible after grading. Surface water runoff should be
collected and directed away from slopes to prevent water from running down the face of the
slope.
1
SHALLOW FOUNDATIONS
Allowable Bearing Pressure
We recommend supporting the structures on continuous wall or isolated column footings
founded on the undisturbed native medium stiff to very stiff silt, boulders or on structural fill
underlain by firm material. Foundations should not be founded on the soft silt material that was
encountered at the surface at variable locations across the site.
r Footings founded as recommended should be proportioned for a maximum allowable soil
bearing pressure of 2,500 psf. The least dimension of column footings should be 24 inches.
The bottom of exterior footings should be at least 24 inches below the lowest adjacent final
grade. The bottom of interior footings should be at least 18 inches below the top of the floor
slab.
(�f G e o E n g i n e e r s 10 File No. 4217 -013 -00- 2130/050498
i
The recommended allowable bearing pressure applies to the total of dead plus long -term
_ live loads. The allowable bearing pressure may be increased by up to one -third for short -term
loads, such as those resulting from wind or seismic forces.
.. Resistance to Sliding
Lateral loads on footings can be resisted by passive earth pressure on the sides of footings
and by friction on the base of the footings. Our analysis indicates that the available passive
earth pressure for footings confined by structural fill or for footings constructed in direct
1 contact with the silt is 350 pcf. Typically, the movement required to develop the available
passive resistance may be relatively large. Therefore, we recommend using a reduced passive
. • pressure of 250 pcf. This value is based on the assumptions that the adjacent confining
4 structural fill or native materials is level and that static ground water remains below the base of
the footing throughout the year. Adjacent floor slabs, pavements or the upper 12 -inch depth of
J
adjacent unpaved areas should not be considered when calculating passive resistance.
A coefficient of friction equal to 0.35 may be used when calculating resistance to sliding.
4
Settlement
" Based on the proposed grading plan, approximate 12 -foot fills are planned during
z,a development. Based on our laboratory testing and analyses, we estimate that total settlement
for footings founded as recommended will be approximately 1 inch and differential settlements
will be less than 1/2 inch.
RETAINING STRUCTURES
The design recommendations for retaining structures are based on the following
assumptions: (1) the walls consist of conventional cantilevered retaining walls or embedded
T building walls, (2) the walls are less than 12 feet in height and (3) the backfill is level, drained
LI and consists of imported granular materials. Reevaluation of our recommendations will be
,. required if the retaining wall design criteria for the project vary from these assumptions.
Li For walls not restrained from rotation, an equivalent fluid pressure of 35 pcf can be used
. for design. An equivalent fluid pressure of 55 pcf can be used for design of walls restrained
from rotation. Footings for the retaining walls should be designed as recommended for shallow
foundations.
Drains that consist of a perforated drainpipe wrapped in a nonwoven geotextile filter should
be installed behind the walls. The pipe should be embedded in a zone of coarse sand or gravel
containing not more than 2 percent passing the U.S. Standard No. 200 Sieve (washed analysis)
.3 and should be sloped to drain toward a suitable discharge.
As stated above, the criteria are based on the assumption of drained conditions. Backfill
material for retaining walls should consist of medium sand, sand and gravel, or well - graded
. sand or gravel, with not more than 2 percent by weight passing the U.S. Standard No. 200
Sieve. A suitable geotextile filter fabric should be placed between the granular materials and
7 , the silt soil to prevent movement of fines into the clean granular material.
F,
G e o E n g i n e e r s
11 File No. 4217 -013-00- 2130/050498
Backfill should be placed and compacted as recommended for structural fill, with the
exception of backfill placed immediately adjacent to walls. Backfill adjacent to walls should be
compacted to a lesser standard to reduce the potential for generation of excessive pressure on
- the walls. Backfill located within a horizontal distance of 3 feet from the retaining walls should
be compacted to approximately 90 percent of maximum dry density, as determined by
ASTM D 1557. The contractor should compact backfill placed within 3 feet of the wall in lifts
less than 6 inches thick using hand - operated tamping equipment, such as jumping jack or
vibratory plate compactors. If flat work, such as slabs, sidewalk, or pavement will be placed
adjacent to the wall, we recommend that the upper 2 feet of fill be compacted to 95 percent of
maximum dry density, as determined by ASTM D 1557. Settlements of up to 1 percent of the
wall height commonly occur immediately adjacent to the wall as the wall rotates and develops
active lateral earth pressures. Consequently, we recommend that construction of flat work
adjacent to retaining walls be postponed at least 4 weeks after construction, unless survey data
indicates that settlement is complete prior to that time.
RESISTANCE TO SLIDING
Lateral loads on footings can be resisted by passive earth pressure on the sides of footings
-- and by friction on the base of the footings. Our analysis indicates that the available passive
�y earth pressure for footings confined by structural fill or for footings constructed in direct
contact with the native soil is 350 pcf. Typically, the movement required to develop the
available passive resistance may be relatively large. Therefore, we recommend using a reduced
passive pressure of 250 pcf. This value is based on the assumptions that the adjacent confining
structural fill or native materials is level and that static ground water remains below the base of
the footing throughout the year. Adjacent floor slabs, pavements, or the upper 12 -inch depth of
adjacent unpaved areas should not be considered when calculating passive resistance.
SLAB -ON -GRADE
Satisfactory subgrade support for building floor slabs supporting up to 250 psf areal loading
can be obtained, provided the building areas are prepared as described previously. A subgrade
modulus value of 150 pounds per cubic inch (pci) may be used to design slabs on grade,
fi provided the site is prepared as recommended. A minimum 6- inch -thick layer of compacted
imported granular material underlain by a geotextile should be placed over the prepared
subgrade to assist as a capillary break. Imported granular material should be crushed rock or
crushed gravel and sand that is fairly well - graded between coarse and fine, contain no organic
matter and other deleterious materials, have a maximum particle size of 1.5 inches, and have
less than 5 percent passing the U.S. Standard No. 200 Sieve. The imported granular material
should be placed in one lift and compacted to not less than 95 percent of the maximum dry
density, as determined by ASTM D 1557. Settlement of the floor slabs supporting the expected
G, 1 design load is not anticipated to exceed 1 inch.
Vapor barriers are often required by flooring manufacturers to protect moisture - sensitive
flooring and flooring adhesives. Many flooring manufacturers will warrant their products only
r�.
' G e o E n g i n e e r s 12 File No. 4217 -013-00- 2130/050498
i , ,
, if a vapor barrier is installed according to their recommendations. Cuts to be made at the site
may result in a relatively shallow depth to ground water elevation. Selection and design of an
, appropriate vapor barrier, if needed, should be based on discussions among members of the
design team. We can provide additional information to assist you with your decision.
SOIL CORROSIVITY
Two soil samples from this site were tested for pH and specific conductivity by North
i Creek Analytical Laboratory. The test results are summarized in Appendix A of this report.
The pH readings are slightly within the acidic range. Based on the measured resistivity
values, the on site -soils are considered to be mildly corrosive to buried metallic structures such
as bare steel, galvanized steel, ductile iron and cast iron.
9
PAVEMENT
The pavement subgrade should be prepared in accordance with the previously described site
preparation, wet weather construction and structural fill recommendations. Our pavement
r recommendations are based on the assumption that traffic at the site will consist of passenger
;.:1
cars and occasional maintenance and delivery truck traffic. We do not have specific
7 information on the frequency and type of vehicles that will use the area; however, we have
.I assumed that traffic conditions will consist of a maximum of 2 trucks per day and a maximum
of 600 cars per day.
We have calculated pavement sections using the above - referenced traffic conditions using a
• design lives of 10 and 20 years, and American Association of State Highway Transportation
I Officials (AASHTO) design methods. The design of the recommended pavement section is
based on an assumed California Bearing Ratio (CBR) of 4 and the assumption that construction
will be completed during an extended period of dry weather. Wet weather construction may
ri require an increased thickness of aggregate base.
Automobile Traffic Truck Traffic and Entrance Areas
~' Asphalt Concrete Base Rock Asphalt Concrete. Base Rock
Design Life Thickness • Thickness • Thickness Thickness
(years) (inches) (inches) (inches) (inches)
10 2.5 6.0 3.5 6.0
20 3.0 8.0
4.0 8.0
rx
The asphalt concrete pavement should conform to Section 00745 of the Standard
Specifications for Highway Construction, Oregon State Highway Division, 1991 Edition, for
light duty asphalt concrete. The aggregate base should conform to Section 02630 of the same
rai specifications, with the exception that the percent passing the U.S. Standard No. 200 Sieve is
less than 5 percent. Aggregate base should be placed in one lift and compacted to not less than
95 percent of the maximum dry density, as determined by ASTM D 1557.
2 G e o E n g i n e e r s 13 File No. 4217 -013-00- 2130/050498
i .
SEISMIC CONSIDERATIONS
Seismicity
' The Cascadia Subduction Zone (CSZ) is the region where the Juan de Fuca Plate is being
subducted beneath the North American Plate. This subduction is occurring in the coastal region
between Vancouver Island and northern California. Evidence has accumulated suggesting that
this subduction zone has generated eight great earthquakes in the last 4,000 years, with the most
recent event occurring about 300 years ago (Weaver and Sherlock, 1991).
-` Two types of subduction -zone earthquakes that might occur are: (1) an earthquake on the
i seismogenic part of the interface between the Juan de Fuca Plate and the North American Plate
on the CSZ with a moment magnitude M = 8 1/2 (interplate event), and (2) a deep earthquake
with a moment magnitude M = 7 on the seismogenic part of the subducting Juan de Fuca plate
E
( intraplate event).
r A significant earthquake could also occur on a nearly local fault that would cause moderate
ground shaking at the site. A geologic map of the site area (Geomatrix, 1995) reports at least
three known faults within a 10 -mile radius of the site. These faults are the Portland Hills Fault
o Zone, the Beaverton Fault Zone, and the Helvetia Fault. Based on geologic information, the
■ Helvetia Fault and the Beaverton Fault Zone are not considered to be active faults. The
--, Portland Hills Fault Zone is judged to be potentially active based on sediment deformation and
topographic expression.
The historical seismic record in Oregon indicates poor correlation between mapped surface
. 0 faults and crustal earthquake epicenters. The current explanation for this difficulty is that
- secondary buried faults are responsible for most of the recorded seismic events near the study
area. Therefore, a moderate earthquake could occur closer to the site than the nearest mapped
L fault. The magnitude of this event would likely be less than a moment magnitude M = 6.0.
Seismic Design Criteria
Li Peak ground accelerations (PGAs) were estimated for this site using a set of maps
developed by Geomatrix, 1995. These maps describe the level of seismic hazard throughout
the State of Oregon on a probabilistic basis. The maps were prepared showing the ground
"` motion levels with specified probabilities of being exceeded.
.7 For purposes of this report, we have defined a maximum probable earthquake as an event
where PGAs have a 10 percent probability of being exceeded over a 50 -year period, and a
Li maximum credible earthquake as an event where PGAs have a 10 percent probability of being
. t exceeded over a 100 -year period. Both design levels include the hazard from both CSZ and
°.k local crustal events as described above. The results are summarized in the following table.
Approximate Expected PGA
n" Probability of Return . Period on Rock
r•
Seismic Design Level Exceedance (years) (g)
Maximum Probable Earthquake 10 percent in 50 years 500 0.20
Maximum Credible Earthquake 10 percent in 100 years 1,000 0.26
a
G e o E n g i n e e r s 14 File No. 4217 -013 -00- 2130/050498
.1.. .
1 •
_s PGAs determined for both seismic design levels are exceeded by those prescribed by the
UBC. Consequently, structural analysis based on the UBC equivalent static design method, and
S2 soils is appropriate.
�)
.: Uniform Building Code Coefficients
i The project site is located within Zone 3 on the seismic zone map of the UBC. We
recommend using a seismic zone factor, Z, of 0.3, and a site coefficient, S2, of 1.2.
Liquefaction
Liquefaction is a phenomenon caused by a rapid increase in pore water pressure that
LI reduces the effective stress between soil particles to near zero. The excessive buildup of pore
water pressure results in the sudden loss of shear strength in a soil. Granular soils, which rely
on interparticle friction for strength, are susceptible to liquefaction until the excess pore
pressures can dissipate. Sand boils and flows observed at the ground surface after an
earthquake are the result of excess pore pressures dissipating upwards, carrying soil particles
,• € with the draining water. In general, loose, saturated sand soils with low silt and clay contents
` are the most susceptible to liquefaction. Silty soils with low plasticity are moderately
susceptible to liquefaction under relatively hi.1 r levels of grouncLshakin:.
LI Based on our explorations and analysis, there is a very low potential for liquefaction at the
site during the postulated earthquakes. Ne • - • s wi not generate excess pore
water pressures during the seismic events described above.
OBSERVATION OF CONSTRUCTION
Satisfactory foundation and earthwork performance depends to a large degree on quality of
construction. Sufficient monitoring of the contractor's activities is a key part of determining
that the work is completed in accordance with the construction drawings and specifications.
Subsurface conditions observed during construction should be compared with those encountered
during the subsurface exploration. Recognition of changed conditions often requires
experience; therefore, qualified personnel should visit the site with sufficient frequency to
detect whether subsurface conditions change significantly from those anticipated.
Included in our proposal submitted to Specht Development, dated April 3, 1998, is a
proposal for construction monitoring services for buildings A and B. We recommend that
GeoEngineers be retained to monitor construction at the site to confirm that subsurface
conditions are consistent with the site explorations and to confirm that the intent of project plans
and specifications relating to earthwork and foundation construction are being met.
LIMITATIONS
We have prepared this report for use by the Specht Development and their consultants in
il the design and construction of the proposed development in the Tigard Triangle development in
Tigard, Oregon. The data and report can be used for bidding or estimating purposes, but our
a
;i,• GeoEngineers 15 File No. 4217 -013-00- 2130/050
:�
ia
i
report, conclusions and interpretations should not be construed as a warranty of the subsurface
conditions and are not applicable to other sites.
7 Our explorations indicate soil conditions only at specific locations and only to the depths
`3 penetrated. They do not necessarily reflect soil strata or water level variations that may exist
. , 1 between exploration locations. If subsurface conditions differing from those described are
i noted during the course of excavation and construction, reevaluation will be necessary.
The site development plans and design details were preliminary at the time this report was
;�1 prepared. When the design has been finalized and if there are changes in the anticipated site
grades or location, configuration, design loads or type of construction for the buildings, the
conclusions and recommendations presented may not be applicable. If design changes are
` J made, we request that we be retained to review our conclusions and recommendations and to
u�
provide a written modification or verification.
The scope of our services does not include services related to construction safety
0 precautions, and our recommendations are not intended to direct the contractor's methods,
techniques, sequences or procedures, except as specifically described in our report for
r
consideration in design.
K.
Within the limitations of scope, schedule and budget, our services have been executed in
accordance with the generally accepted practices in this area at the time this report was
v
prepared. No warranty or other conditions, express or implied, should be understood.
li Ia►
i1
0
1
3
I
3 G e o E n g i n e e r s 16 File No. 4217 -013-00- 2130/050498
1
We appreciate the opportunity to be of continued service to Specht Development. Please
call if you have questions regarding this report.
Yours very truly,
GeoEngineers, Inc. PROrepn
+ '� 1N "Q I'
l o t
• EGO Marcell. 1. Boye r .
1. y la 20 ,'+ • �4� Geotechnical Engineer
3,..,t 94
N,
,..,
r David L. Thielen, P.E.
Associate
3
MMB:DLT:m1n
] Document ID: 4217013rgeo.doc
t Copyright 1998 by GeoEngineers, Inc. All rights reserved.
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- , O Reference: This map reproduced with permission granted by THOMAS N
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4 .., BROTHERS MAPS. It is unlawful to copy or reproduce all
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` 1 A without permission.
git VICINITY MAP
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f■ Geo " Engineers • 4k■/' FIGURE 1
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Q W 6.
- o &I w 0 100 200
EN CC
• (71 u) E SCALE IN FEET
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EXPLANATION: Cq
o Ii •
o TP - TEST PIT
0
18.5 DEPTH TO BOULDERS (IN FEET) C6
BOULDERS NOT ENCOUNTERED TO
.) DEPTHS EXPLORED
0 Note: The locations of all features shown are approximate.
0
,n
1 _ Pd1.._ ' I QITC el wLI
9 • 1 .
'
N
r'; a EXISTING GROUND SURFACE
1
s.
IS l�
o ,
a
" Ilk o Dw1
F1F3 N IIM 2
1 H
1
1
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EXCAVATION BASE —\ la .
0 / /
Dw2 2 � _ r
gi /� �� .
D A�� D A AIM MIR .
al .
1
A AEI
IMM
MIS
3 „
k , 4, k j , k .1, 4, k k 4, ,
(D — D Y Y + D — D 1 )
. Kp( —7 )(D — Dw2) Ka(Ys —Yw)(H + D — D
Kp Ka
K = Coefficient of Active Pressure
!fti = 0.27
K = Coefficient of Passive Pressure
= 3.7
Y = Saturated Unit Weight (below water table)
t = 120 pcf (pounds per cubic foot)
Y = Moist Unit Weight (above water table)
id co
= 115 pcf
Yw = Unit Weight of Water
o = 62.4 pcf
1 in
0
Oia
Notes: 1. Figure should be used only in conjunction
with qualifications in report text.
cc
m 2. A factor of safety of 1.5 on passive pressure
3 ., m is recommended for design purposes.
0
0
LATERAL EARTH PRESSURES
0 o TEMPORARY SHORING
G eo �� Engineers FIGURE 3
N
H a
0
U
W
•
- ' . 12" Minimum //
' \ . : O. 0 0 : ° • • O D' \
IA / • Do ' O° 0 °o . I 0 I ). • 000o 00
Drain Rock \\ ; °o0a oa o o D ov000 �o ° / •
r a 0 . . D o,Doo
� • oDo o 00 0 00 -
°°: 0 ° '°° • 0 '
..
:° ; :0.0 Varies
'O00p •ooa•00 0 Ow Ow
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O ° Od ° •o qo : ° O0..o e
.s Geotextile :O Oo
Qlf� • � °. 40q p ° ' p o • op� . o p ° °• 0 . °O •
00 0- 0 .0 . - r nil
6 " Perforated o ° °e ° ° : a •*o• : •
Pipe /" 0% v p pa,* P 0 0 Sou •o 0 00'
1 .° °op° �o a0 0
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J / - 8 , , , ,2, 0 . :0. o : G /
\• o 0 %'
w
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1 Width = 2'
03
rn
in
0
in
0
cc
di
i m
m
o
° SCHEMATIC OF
II o— "' - 1 ►'' RECOMMENDED SUBSURFACE DRAIN
Geo., ngineers
� � FIGURE 4
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i
•
APPENDIX A
FIELD EXPLORATIONS AND LABORATORY TESTING
FIELD EXPLORATIONS
ri General
i Subsurface conditions at the sites were explored by excavating 19 test pits at the Tigard
Triangle development on April 22 and 23, 1998 at the approximate locations shown in
Figure 2. The test pits were excavated using a John Deere 490 track - mounted backhoe
1 provided by Greg VanDeHey Soil Sampling of Forest Grove, Oregon. The test pit excavations
extended to a maximum depth of approximately 19 feet. Exploration locations were chosen
{ based on a preliminary site development plan provided to our office by Specht Development
and VLMK Consulting Engineers. The locations of the explorations were determined in the
field by pacing from site features. The locations and elevations should be considered accurate to
the degree implied.
Soil Sampling
Representative soil samples were obtained either from the test pit walls and /or base using
the backhoe bucket. Materials encountered in the test pits were classified in the field in general
accordance with ASTM D 2488, which is described in Figure A -1. Classifications and
sampling intervals are shown in the test pit logs (Figures A -3 through A -21).
9 LABORATORY TESTING
Introduction
Soil samples obtained from the test pits at the site were tested in GeoEngineer's soil testing
E laboratory. Laboratory tests were performed on selected samples to verify field classifications
and determine the moisture, density and consolidation properties of the site soils. Corrosivity
testing was subcontracted to North Creek Analytical laboratory. Descriptions of the tests are
included below.
Classification, Moisture Content and Density
All of the samples obtained from the explorations were examined visually to confirm or
modify field classifications. The laboratory soil classifications are included in the test pit logs
if those classifications varied from the field classifications.
The natural moisture content of selected soil samples were tested in accordance with ASTM
F. D 2216. The natural moisture content is a ratio of the weight of the water to soil in a test
sample and is expressed as a percentage. The moisture contents are included in the test pit logs
included in this appendix.
We tested selected soil samples m general accordance with ASTM D 2937 to determine the
in -situ dry density (dry unit weight) The dry density is defined as the ratio of the dry weight
1 G e o E n g i n e e r s A -1 File No. 4217-013-00-2130/050498
i 1 .
of the soil sample to the volume of that sample. The dry density is typically expressed in
pounds per cubic foot (pcf). The dry densities are presented in the test pit logs in this
, appendix.
y Consolidation Testing
i 1 A one - dimensional consolidation test was completed on one relatively undisturbed soil
sample obtained from the test pit excavations. The test was conducted in general accordance
with ASTM D 2435. The test measures the volume change (consolidation) of a soil sample
under predetermined loads. The results of the consolidation test are included in Figure A -22.
Corrosivity Testing
Two samples from this site were tested to determine the relative corrosivity. The pH and
specific conductivity of the samples were determined in general accordance with Environmental
Protection Agency (EPA) Method 9045B and EPA Method 120.1/9050, respectively. These
tests measure the relative corrosivity of the site soils. The results of the corrosivity testing are
included below.
,t'
TABLE 1
3 pH AND RESISTIVITY
Depth of Sample Resistivity
Test Pit Number (feet) pH . (Ohm -cm)
TP -13 2 5.82 23,650
TP -16 2 5.70 48,300
L1
3
1
1
3 4
7.,
F
j
3 G e o E n g i n e e r s A - 2 File No. 4217 -013-00- 2130/050498
-i •
SOIL CLASSIFICATION SYSTEM
--I GROUP
MAJOR DIVISIONS SYMBOL GROUP NAME
G' ij
GRAVEL CLEAN GW WELL- GRADED GRAVEL, FINE TO COARSE GRAVEL
COARSE GRAVEL '
GRAINED GP POORLY- GRADED GRAVEL
SOILS More Than 50%
of Coarse Fraction GRAVEL GM SILTY GRAVEL
i Retained WITH FINES
on No. 4 Sieve GC CLAYEY GRAVEL
t ; More Than 50%
L SAND CLEAN SAND SW
WELL GRADED SAND, FINE TO COARSE SAND
Retained on
No. 200 Sieve SP POORLY- GRADED SAND
F t]
More Than 50%
S
of Coarse Fraction SAND SM SILTY SAND
Passes WITH FINES
SC CLAYEY SAND
'• No. 4 Sieve
FINE SILT AND CLAY ML SILT
GRAINED INORGANIC
1 u SOILS CL CLAY
Liquid Limit
'`7 Less Than 50 ORGANIC OL ORGANIC SILT, ORGANIC CLAY
SILT AND CLAY MH SILT OF HIGH PLASTICITY, ELASTIC SILT
More Than 50%
INORGANIC -
,,. Passes CH CLAY OF HIGH PLASTICITY, FAT CLAY
�L Y No. 200 Sieve
Liquid Limit
50 or More ORGANIC OH ORGANIC CLAY, ORGANIC SILT
7
.1
HIGHLY ORGANIC SOILS PT PEAT
NOTES: SOIL MOISTURE MODIFIERS:
1. Field classification is based on visual examination of soil Dry - Absence of moisture, dusty, dry to the touch
1 in general accordance with ASTM D2488 -90.
Moist - Damp, but no visible water
" 2. Soil classification using laboratory tests is based on
ASTM D2487 -90. Wet - Visible free water or saturated, usually soil is
obtained from below water table
3. Descriptions of soil density or consistency are based on
interpretation of blow count data, visual appearance of
soils, and /or test data.
9 en
O.
N
0 •
i
h p SOIL CLASSIFICATION SYSTEM
W Geo Ne Engineers
FIGURE A -1
0
2 A.
,,,,,
• • /
d
0
Vt Ce
• Y LABORATORY TESTS: SOIL GRAPH:
1-
0
J AL Atterberg limits SM Soil Group Symbol
a CP Compaction (See Note 2)
CS Consolidation
0 DS Direct Sheer
:. o GS Grain - size Distinct Contact Between
F- %F Percent fines Soil Strata
F ° x HA Hydrometer analysis
o SK Permeability Gradual or Approximate
0 SM Moisture content ,. Location of Change
• 0 MO Moisture and density Between Soil Strata
0 ST Swelling test
TX Triaxial compression SZ Water Level
UC Unconfiend compression
CA Chemical analysis Bottom of Boring
BLOW- COUNT /SAMPLE DATA:
'1
: Al
_ 10 0 Location of sample obtained
7 Blows required to drive a 1.5 -inch I.D. in general accordance with
(SPT) split - barrel sampler 12 inches 7 Standard Penetration Test
or other indicated distances using a (ASTM D 1586) procedures
140 -pound hammer falling 30 inches._
"l 26 m Location of SPT sampling
attempt with no recovery
"P" indicates sampler pushed with ■ Location of relatively
'.� weight of hammer or against weight of drill rig. undisturbed sample
Ki
® Location of disturbed sample
P.P. indicates penetration resistance
measured in the field using a pocket ❑ Location of sampling attempt
penetrometer. Resistance is measured with no recovery
in tons per square foot (TSF). P I Location of relatively undisturbed
f
sample obtained using a 3 -inch-
—
diameter thin -wall sample tube.
Sample obtained in general
: , t accordance with ASTM D 1587.
,
L
® Location of grab sample
IS NOTES:
1. The reader must refer to the discussion in the report text, the Key to Test Pit
Symbols and the exploration Togs for a proper understanding of
0
0 subsurface conditions.
,,:j, o 0 2. Soil classification system is summarized in Figure A -1.
0
0
0
0 o �� KEY TO TEST PIT LOG SYMBOLS
0 GeoEnglneers FIGURE A -2
0
• TEST DATA TEST PIT TP -1
;Ti DESCRIPTION
666 Moisture Dry
Content Density P.P. Group
Lab Tests (%) (pcf) (tsf) Samples Symbol
0 L. 0 L (GM Dark brown silty gravel (loose, moist) (fill) 0
ML Brown silt with trace fine sand (very stiff, moist)
-
"` 1 - 3.5
2 - 1.25 Grades with clay (stiff, moist to wet)
3 - 3.5 N / ML Brown -gray mottled silt with trace fine sand (very stiff, moist)
4 - 3.5
6`
5 — / ML Brown silt with fine sand (stiff, moist) — 5
' 6 SM 29.2
7 - -
w
w
LL
Z 9 - -
a =
H
0 10— —10
11 -
c y 12
`� 13 -
i,
co
m
u, 14 -
r E
g 15— —15
2
16
':a
) 17 - -
18 - Grades to gray -
o Boulders in a silt matrix
-] vA -4 : BOULDER
oo ..s°
'7 1 ,,,,,,00-,.. Test pit completed at 19.0 feet because of refusal on boulders on
0 19 - °°°° 04/22/98
Slow ground water seepage observed between 2.0 and 3.0 feet
o No caving observed
^ 20 — Note: See Figure A -2 for explanation of symbols — 20
r, a
P.P. = pocket penetration test
/ � p► LOG OF TEST PIT
Geo � Engineers FIGURE A -3
j
TEST DATA TEST PIT TP-2
i.:1• ,
7 ' DESCRIPTION
Moisture Dry
Content Density P.P. Group
Lab Tests (%) (pcf) (tsf) Samples Symbol
0 — —0
'OL Dark brown organic silt with roots (very soft, moist to wet)
-.1 ......-.-A-.....
(12-inch-thick root zone)
°/, ........A-A.."...
1 - ML Brown-gray mottled clayey silt with trace fine sand (stiff, moist
,1 N to wet)
2 - -
• .1 1.5
- 3.25 Grades to very stiff and moist -
. i
.. a
4 - -
MD 32.8 87 3.25
I
CS
11 5 — Grades to brown — 5
F . I 6 - ML Brown silt with fine sand (stiff, moist)
7 -
:,.
8 - -
I--
w
Lu
U.
z 9 _ Grades to brown with red-brown layers
1
1-
Lu
7:1 c 10 — — 10
i
11 -
1 2 -
1 3 -
cn
14 -
3 i
co
15
2
5
] (2 ) 16 - Grades to gray
I .
Xi c )2 Test pit completed at 19.0 feet on 04/22/98
a g,
19 - Slow ground water seepage observed between 5.0 and 17.0 feet
No caving observed
7 = 7 .)
20 — Note: See Figure A-2 for explanation of symbols — 20
', c 4
P.P. = pocket penetration test
LOG OF TEST PIT
Geo kail Engineers
FIGURE A-4
111
9 . TEST DATA TEST PIT TP-3
•
DESCRIPTION
I Moisture Dry
Content Density P.P. Group
Lab Tests (%) (pcf) (tsf) Samples Symbol
0 — — 0
OL Dark brown to black organic silt with roots (soft, moist)
,........A,...A.
1.0 ML
(8-inch-thick root zone)
.z.., 1 - Brown silt with trace fine sand (soft to medium stiff, moist) _
0.75-1.5
ri 2 - 3.5 Grades to very stiff -
•
3 - _
4 - -
2.75
5 — — 5
•
6 - -
7 - _
8 - ./'---. ML -
Brown and red-brown silt with trace clay (stiff, moist)
w
l z 9 _
SM 29.6
VI
i
1—
a
w
i n
10— —10
11 - -
',.
1
1 2 -
■af.
1 3 -
! co
a
Ln 1 4 - -
7 E
i...-1 E
15— —15
2
2
1 ( 4
16- -
17- -
weeeo BOULDER Boulders in a silt matrix
...:re.,
18 - -
O 0::4
6
Test pit completed at 18.5 feet because of refusal on 04/22/98
6 19 - No ground water seepage observed -
6 No caving observed
L 20 — Note: See Figure A-2 for explanation of symbols — 20
3 ,
P.P. = pocket penetration test
1 9)
4 LOG OF TEST PIT
Geo 7 . 1741%Engineers
4 k\O a. FIGURE A-5
I -
TEST DATA TEST PIT TP-4
. .;i. '
DESCRIPTION
Moisture Dry
Content Density P.P. Group
Lab Tests (%) (pcf) (tst) Samples Symbol
0 0
OL Dark brown organic silt with roots (stiff, moist) (8-inch-thick
] 1.5 ML root zone)
1 -
Dark brown silt with trace fine sand (stiff, moist)
-
1.5
Grades to brown
RI
2- 2.0
7 3 - 2.25
N Grades to brown-gray -
4 -
3.0 -
— —
ML Brown fine sandy silt (stiff, moist)
9 6- -
7- _
q
8 - -
1- SM 30.7
M ML Brown and red-brown silt with trace fine sand
Li,
w
u.
i-
n.
w
0 1 0 — —10
:..
1 1 - -
, r.
f'.
k
12- -
13 - -
] co
0)
L 14 - -
7 .
E
tA En
2
15— —15
• E
1 6
16 - -
17 - Grades to gray -
]
18 - -
0
7 C.7 15M BOULDER Boulders in a silt matrix
2 - , i 19 -
o Test pit completed at 19.0 feet because of refusal on 04/22/98
th No ground water seepage observed
3 No caving observed
20 — Note: See Figure A-2 for explanation of symbols — 20
P.P. = pocket penetration test
U .... 4 sit LOG OF TEST PIT
Geo kt■P Engineers
.••• FIGURE A-6
I
TEST DATA TEST PIT TP-5
b: . ,
. DESCRIPTION
Moisture Dry
Content Density P.P. Group
Lab Tests (%) (pcf) (tsf) Samples Symbol
0 —
OL Dark brown organic silt (soft, moist) (12-inch-thick root zone) —0
..:' 0.75 , .....„..A.,A, ,, ..
1 - -
ML Brown silt with trace fine sand (medium stiff to stiff, moist)
'.1
2- 2.0 -
1 3 - 2.75 -
4 -
2.75 -
5 — —5
6 - '-' ML Brown silt with fine sand (stiff, moist) -
!A
7 -
SM 28.9 -
?
1
8 - -
i-
u,
u,
1-
a.
ui
p
10— —10
11 - -
1 2 - -
Test pit completed at 12.0 feet on 04/22/98
No ground water seepage observed
No caving osberved
-
1 3 -
co
0)
yr
to 14 - -
A cE
2 1 5 — —15
2
6'
..... - 1 6 - -
1 7 - -
.0 .
iA
18 - - -
0
cf c'',,
:..,j 6
0 1 9 - -
6
O
20 — Note: See Figure A-2 for explanation of symbols — 20
a
P.P. = pocket penetration test
1 ...,41it LOG OF TEST PIT
Geo 4-0 Engineers
1' FIGURE A-7
1
.i
9 : • TEST DATA TEST PIT TP-6
j DESCRIPTION
Moisture Dry
,... Content Density P.P. Group
Lab Tests (%) (pcf) (tsf) Samples Symbol
0 —
ML Dark brown silt with trace fine sand (soft to medium stiff, — 0
moist) (12-inch-thick root zone)
1 - SM 28.8 0.5-1.5 _
2 -
:1 2.0-2.5 -
ML Brown silt with trace fine sand (very stiff, moist)
3 - -
SM 25.1 3.5
,::.. ,..,.
..
I
0
4 - 3.5 -
5— —5
6- _
7 - -
j
w
u_
] i
1—
a
Lu
0
10— —10
a
11 -
ML Brown silt with fine sand (stiff, moist)
• , f t i:
12 - ..
13 - -
BOULDER Boulders in a silt matrix
on 14 - oveeoto
owoto -
e
0 i , > ewe"
Test pit completed at 14.5 feet because of refusal on 04/22/98
2 15 — No ground water seepage observed — 15
2 No caving observed
5
1 Y, 16 - -
17 - -
I ,
i
18 - -
o
ci
a g 19 - -
A
3
11 A 20 — Note: See Figure A-2 for explanation of symbols —20
U , v P.P. = pocket penetration test
1 .1.10,t Engineers
e LOG OF TEST PIT
Geo
*
Now FIGURE A-8
I ,
' 9 • .• TEST DATA TEST PIT TP-7
DESCRIPTION
1 Moisture Dry
ri Content Density P.P. Group
0
Lab Tests (%) (pcf) (tsf) Samples Symbol
' ML Dark brown silt with trace fine sand (medium stiff, moist to — 0
LI 1.5 wet) (12-inch-thick root zone)
1 - -
2.0 ML Brown-gray mottled silt with trace fine sand (stiff, moist)
2 -
SM 30.9 2.0
N
3 -
_CP 3.0 ML Brown silt with trace fine sand (very stiff, moist)
t.•
k i
4- -
3.5
] 5 — ML Brown silt with fine sand (stiff, moist) — 5
6 -
SM 27.2
..;.'
7 - -
6!,
8 - -
1—
LAJ
Li.
1—
a
w
cl
10— —10
11 - _
12-inch-diameter boulder encountered
12 - -
Test pit completed at 12.0 feet on 04/22/98
No ground water seepage observed
13 - No caving observed
-
0)
14 - -
:'• ' i
]
15— —15
2
, 5
16 - -
17 - -
18 - -
o
9
p-,
3 := 20 — Note: See Figure A-2 for explanation of symbols — 20
P.P. = pocket penetration test
...- 9 LOG OF TEST PIT
0 . -
Geo k•, Engineers
Nei FIGURE A-9
i ,
il , ,
TEST DATA TEST PIT TP -8
DESCRIPTION
; Moisture Dry
Content Density P.P. Group
Lab Tests (%) (pcf) (tsf) Samples Symbol
0 — � OL Dark brown organic silt (soft, moist to wet) (12- inch -thick root —0
ML zone)
1 - Brown silt (soft, moist to wet) -
0.5
1 2 SM 31.9 0.5 -2.0 N ML Brown -gray mottled silt with trace fine sand (soft to stiff, moist)
3 - 2.5
t',
4 - 2.5 Grades to brown and stiff to very stiff -
it- — 5
5 — 3.0
6 MD 28.2 96 ! / ML Brown silt with fine sand (stiff, moist) -
7 - -
C Encountered 12- inch - diameter boulder
8
w
u. ; BOULDER Boulders in a silt matrix
LL 000000
,006000
I ? 9 - Cd666o -
Test pit completed at 9.0 feet because of refusal on boulder on
=
F . 04/23/98
w Slow ground water seepage observed between 3.0 and 4.0 feet _ 10
0 10 — No caving observed
11
12
13
m
14 - -
E
Qa1 2 15— —15
2
1 ( 16
17 - -
5
18 -
0
frx M
ij - 19
0
1, 20 — Note: See Figure A -2 for explanation of symbols — 20
a
P.P. = pocket penetration test
oti. LOG OF TEST PIT
Geo W oEngineerS FIGURE A -10
I
;;I:
TEST DATA TEST PIT TP-9
t . .
DESCRIPTION
Moisture Dry
. Content Density P.P. Group
Lab Tests (%) (pcf) (tsf) Samples Symbol
0 — 0
OL Dark brown organic silt (soft, moist) (10-inch-thick root zone)
,...................
1
I■4u — ML Dark gray-brown mottled silt with trace clay (soft to medium
1 - stiff, moist) -
SM 26.2 0.5-1.5
Encountered boulders at 2.0 feet
: 2 - SM 24.9 1.5-2.25 N Grades to dark gray silt with trace clay (medium stiff to stiff, -
moist)
3
9 - 2.0 ML Brown silt with trace fine sand medium stiff, moist
( , ) -
BOULDER Boulders in a silt matrix
4 - -
Test pit completed at 4.0 feet because of refusal on boulders on
0 No 04/23/98
5 — ground water seepage observed 5
—
No caving observed
6- -
4 1
7- -
1
i
8 - -
I—
LL,
iu
u.
z 9 _
m -
1—
Q.
a
10— —10
gl
11 - -
13- -
i!;■' , , ,.. ,
a ;
d •
14 - _
1 c
A
E
2 15— —15
2
1 6
,
16- -
18 - -
1 E
11 A
19- -
itte 6
Z
:1 A 20 — Note: See Figure A-2 for explanation of symbols — 20
ni.
P.P. = pocket penetration test
1
L ...„..... LOG OF TEST PIT
Geo kroil Engineers
.e. FIGURE A-11
3
TEST DATA TEST PIT TP-10
DESCRIPTION
,..': • Moisture Dry
Content Density P.P. Group
Lab Tests (%) (pcf) (tsf) Samples Symbol
0 —, — 0
OL Dark brown organic silt (soft, moist to wet) (12-inch-thick root
...................
ML zone)
3
1 - 1.5 Brown silt with trace fine sand (stiff, moist) _
I
2- 2.0
ni
3 -
51 MD 29.6 91 2.0
I
4- -
a 5 — —5
-
7 - N/ML Brown silt with fine sand (medium stiff to stiff, moist) -
L,1
i—
u,
u,
u_
1 -
i
1—
o.
til
0 10— — 10
,1_ -
Boulder encountered
"•• 12 - - -
Test pit completed at 12.0 feet on 4/23/98
No ground water seepage observed
) No caving observed
13- -
ai 2
-
• 14- -
1 .1
j CO
• 1 5 — —15
2
5
16- -
.
i .
F4
“a -
A g
19- -
6
3
20 — Note: See Figure A-2 for explanation of symbols — 20
P.P. = pocket penetration test
.1 .... git, LOG OF TEST PIT
Geo "" e Engineers
4I k\ FIGURE A-12
1 ,
d TEST DATA TEST PIT TP-11
• ..
DESCRIPTION
Moisture Dry
Content Density P.P. Group
Lab Tests (%) (pct) (tsf) Samples Symbol
0 —
ML Dark brown gravelly silt with debris (soft, moist) (6-inch-thick — 0
root zone) (fill)
1 0.75 ML Brown clayey silt (medium stiff, moist to wet) _
1 2 - SM 26.3 1.5 ML Brown silt with trace fine sand (stiff to very stiff, moist) -
3 - _
1 3.0
,. .
4 - -
3.5
5— —5
6- -
g
7- -
]
8 ML
1-. Brown silt with sand (medium stiff, moist)
Lu
ill
u_
I z 9 - _
i
1-
o_
Lu
0
10— —
11 - -
nvnoz.
N,.....„ g OULDER Boulders M a silt matrix
F:
12 - -
Test pit completed at 12.0 feet because of refusal on 04/23/98
No ground water seepage observed
No caving osberved
1 13- -
li gi
4'
Lo 14 - -
1 i
15— —15
m
1 ))5 16 - -
\ '
1 .
18 - -
o
. c..)
0/1 r1 20 — Note: See Figure A-2 for explanation of symbols — 20
tr 't P.P. = pocket penetration test
Geo Engineers LOG OF TEST
FIGURE A-13
pi
TEST DATA TEST PIT TP-12
•
li , •
1 -
Moisture Dry DESCRIPTION
Content Density P.P. Group
Lab Tests (%) (pct) (tsf) Samples Symbol
0 —
OL Dark brown organic silt (soft, moist to wet) (16-inch-thick root — 0
71 — zone)
ML
A Brown silt with trace fine sand (soft to medium stiff, moist) -
1 - SM 22.4 1.0
2 - 1.75 Grades to stiff -
3 - Grades to very stiff -
1 SM 29.0 2.75
4- -
3.25
.._
r.,. 5 — — 5
6 -
11
7 - -
fl.
a
8- _
1-
w
ui
u_
3 z 9 - -
.
0_
w
0 1 0 - -10
11 - 16-inch-diameter boulder encountered at 11.0 feet -
12 -
Test pit completed at 12.0 feet because of refusal on 04/23/98 -
No ground water seepage observed
No caving observed
1 3 - -
Ts.
LO
14- -
7 i
LI 1 5 — —15
2
(1) 1 6 - -
17 - -
18 - -
o
cl
1 7,
iSii g 1 9 - -
()
":".7'
j 20 — Note: See Figure A-2 for explanation of symbols — 20
13. , t
P.P. = pocket penetration test
3 .... 01 , LOG OF TEST PIT
Geo Engineers
Now FIGURE A-14
3
fr: ' ,
TEST DATA TEST PIT TP-13
DESCRIPTION
Moisture Dry
Content Density P.P. Group
Lab Tests (%) (pcf) (tsf) Samples Symbol
0 OL Brown organic silt (soft, moist) (6-inch-thick root zone) — o
-.......,
0.75 ML Brown silt with trace fine sand soft to medium stiff, moist
( , )
1 -
0.75 -
2 - -
SM 28.9 1.25
N
3 - 1.75 Grades to stiff -
4 - 3.0 Grades to very stiff -
] 5— —5
6 - -
9 N
7 - _
e.''.
8 - -
1—
iu
iu
I x
1—
a
ill
a
10— —10
11 - -
t.q
a 1 2 - - Test pit completed at 12.0 feet on 04/23/98 -
Slow ground water seepage observed at 4.0 feet
No caving observed
] co
13 - _
a)
14 - _
1 i
2 15 — —15
2
5
I u
4 - 16- -
g
I (I;
in
S
' 20— Note: See Figure A-2 for explanation of symbols —20
Tr
P.P. = pocket penetration test
,,, .... . gib LOG OF TEST PIT
Geo .....e Engineers
.•••• FIGURE A-15
1 ' • TEST DATA TEST PIT TP-14
0 . .
DESCRIPTION
Moisture Dry
Content Density P.P. Group
Lab Tests (%) (pcf) (tsf) Samples Symbol
0 — — 0
OL Dark brown organic silt (soft, moist to wet) (14-inch-thick root
„.....
i.1 zone)
a VR ML
1 - SM 31.4 1.25 Brown silt with trace fine sand (medium stiff to stiff, moist) _
1
2- -
1.25
3- -
1.5
4 -
1.5 -
2.0 — 5
6 -
Test pit completed at 6.0 feet on 04/23/98
No ground water seepage observed
7 - No caving observed
-
8 - -
I--
u,
Lu
u.
1—
a.
Lu
0
10— —10
11 - -
K
id 12- -
9 j 2 13 - -
iii 14 - -
I E
ha. 2 1 5 — —15
2
I (---i 1 6 - -
17 - -
]
18 - -
.
3 2
. 1 9 - -
6
( 7'
, : 2
a 20 — Note: See Figure A-2 for explanation of symbols
— 20
P.P. = pocket penetration test
1 .... . At LOG OF TEST PIT
Geo k Engineers
....0 FIGURE A-16
i
• TEST DATA TEST PIT TP-15
, . • •
DESCRIPTION
Moisture Dry
Content Density P.P. Group
0 — Lab Tests (%) (pcf) (tsf) Samples Symbol
— 0
OL Dark brown organic silt (soft to medium stiff, moist)
71 ..................
1.0 ML
(8-inch-thick root zone)
.
1 - Brown silt with trace fine sand (soft to medium stiff, moist)
1.0
-
2- 1.0
3
71 - SM 31.6 2.25 Grades to brown-gray mottled silt with trace fine sand (very -
M stiff to hard, moist)
4 -
4.0 -
4.0 Test pit completed at 5.0 feet on 04/23/98
No ground water seepage observed
6 - No caving osberved
-
7- _
! ;
8- -
LL,
Lu
1 z
9- -
t. m
1—
a
Lu
a 10— —10
71
Li
11 - -
:i L. 12 - -
J�
13 - -
co
o
14 - _
i I
_I 64 15 — —15
2
5
1 ' 16 - -
17 - -
. t
.:,:.
18 - -
0
7 1 m
i 0 19 - -
— 9
r
d vc.3
P. 20 — Note: See Figure A-2 for explanation of symbols — 20
c.„.
‘,
P.P. = pocket penetration test
c' 1
LOG OF TEST PIT
Geo .."'" Engineers
III_ FIGURE A-17
;:;
* . TEST DATA TEST PIT TP-16
ii. . •
DESCRIPTION
Moisture Dry
Content Density P.P. Group
o — Lab Tests (%) (pct) (tsf) Samples Symbol
OL Dark brown silt (soft, moist) (14-inch-thick root zone) — 0
rg ,....,,,A.....
LI i - ML
0.5-1.0 Brown-dark brown silt with trace fine sand (soft to medium
ri N stiff, moist to wet)
1 2 - 0.5-1.5
3 -
0.5-2.0 ML Brown silt with trace fine sand (very stiff, moist)
4 - -
3.75
ti 5— —5
6- -
7- -
8- -
1-
w
w
u_
3 z
9- _
1
1-
0
i.0
0 10— —10
3
SM 29.2
N
11 - -
] 12- -
1:1,Tga BOULDER Boulders in a silt matrix
13 -
Test pit completed at 13.0 feet because of refusal on 04/22/98
a) No ground water seepage observed
No caving observed
ia 14 - .
3 s.
il
2 15— — 15
2
>
1 9, 16- -
1 ,
18 - -
8
3 .c,
• A 0 19 - -
9
v.,
3
A 20 — Note: See Figure A-2 for explanation of symbols — 20
P.P. = pocket penetration test
P. LOG OF TEST PIT
Geo 1•
4 ‘`ae i FIGURE A-18
i ,
i gi 1 ,
TEST DATA TEST PIT TP-17
] * DESCRIPTION
Moisture Dry
t Content Density P.P. Group
Lab Tests (%) (pcf) (tsf) Samples Symbol
0 — OL Dark brown organic silt (soft, moist) (14-inch-thick root zone) —o
3 1 moo-- ML _
1.25
lCI Brown silt with trace fine sand (medium stiff, moist to wet)
1 . 2 - 2.0-3.0 N Grades to stiff and moist -
3 - _
1 2.25
"....,
4 - -
E
5— —5
6 - ML Brown silt with fine sand (stiff, moist) -
7- -
1-
w
u,
u.
_
I x
F-
L.0
3 R,
'(.?.
o 10- -10
11 - -
1 2 - 13 -
-
•?>;V:U BOULDER Boulders in a silt matrix -
U co
en • • •
.0.0.0 ,...,*
000000
,,00•0°
iii 14 -
.00.0,4,
0.00e-,
] c ..›.(700*,,,,,,,
.,
1
,g40,,, : ;.0.
• co
ve.g. .i —15
2 1 5 — Test pit completed at 15.0 feet because of refusal on 04/22/98
f 2
No ground water seepage observed
6
1 6 - No caving observed
, n -
o
] c:2 c4
'• 6 1 9 - -
9
cl
:I I : 20— Note: See Figure A-2 for explanation of symbols — 20
P.P. = pocket penetration test
il ..- . 9 LOG OF TEST PIT
Geo Noe• Engineers
41 k1I/ P FIGURE A-19
';'-.' •
If'
•
• TEST DATA TEST PIT TP -18
•
DESCRIPTION
Moisture Dry
Content Density P.P. Group
Lab Tests (%) (pcf) (tsf) Samples Symbol
0 0 0 ( GM Gray -brown silty gravel (loose, moist) (fill) (8- inch -thick root — 0
;f 0 � C zone)
1 - °�` -
ML Light brown -gray mottled silt with trace fine sand (soft to
51 0.25-1.25 medium stiff, moist to wet)
r 3 N 0 0 l_. (GM Gray silty gravel with occasional fine sand (medium dense,
ML moist to wet) (alluvial)
4 - Brown silt with trace fine sand and clay (soft to medium stiff, -
SM 22.4 0.5 -1.5 N moist)
i'r
5— —5
4 - 6 - ML Brown silt with fine sand (medium stiff, moist)
7 SM 28.0
1-
8 -
w
w
w
: Z g - -
2
H
w
<, 10— —10
11 - -
4'
l0 12 - -
`00000 ' BOULDER Boulders in a silt matrix
0 000 0
13 - .000000
Test pit completed at 13.0 feet because of refusal on boulder on
EL
04/22/98
v Slow ground water seepage observed at 3.0 feet
a 14 Slight caving observed in upper 4 feet
��
'J E
Cc; 15— —15
2
U
l ' 16 -
r
17 - -
18 - -
o
3 ,,,,,.,
• _
0 19 -
° — 20
^_ 20 — Note: See Figure A -2 for explanation of symbols
J N
Ti.
P.P. = pocket penetration test
./� LOG OF TEST PIT
Geo � i Engineers FIGURE A -20
I
• TEST DATA TEST PIT TP -19
;: DESCRIPTION
i.- Moisture Dry
Content Density P.P. Group
Lab Tests (%) (pcf) (tsf) Samples Symbol
0 OL Dark brown organic silt (soft, moist) (12- inch -thick root zone) — 0
ti
1 ML Brown silt with trace fine sand (medium stiff, moist) -
?.�9 2 - -
3 -
t `
.4\
4 -
El 5— —5
4 6 -
7 - _ •
8 - -
H
w
w _
LL
? 9 -
H
UJ
0 10— —10
>< <s <o:BOULDER Boulders in a silt matrix
,000000
11 - z 000000 -
Test pit completed at 11.0 feet on 04/23/98
No ground water seepage observed
{ %' 12 No caving observed _
13 - -
E�
to
co
,� 14 -
c
E
2 15— —15
2
U
16
} 17
I
18 - -
O
O 19
M
0 °' -- 20
^_ 20 — Note: See Figure A -2 for explanation of symbols
N
P.P. = pocket penetration test
�/ gyp► LOG OF TEST PIT • Geo l Engineers FIGURE A -21
I
11 r
4 0.00 —
..1 ,
•
•
•
•
:.. 1
0.02 — ...__. —_.._ _ ,_...._ .._ .
1
i
i
9 i
. . "
. . . •
. . . .
. , „
. . •
•
i
1 I i i ! j I I i i I l i
•
9 .
1 j
i i i` —j 1 i i
t i
U ' l l i I
c 1
, i .
Z
1 i •
O i i • j I •
Q i i • • 1
• Q
J 1
;•:.] 0
•
•
•
Z i
O 0.06 - __........— __.....__..__ __._;._...:._!._... ..____.__.__.__,.___.........__ _ _ _ _ _
i
0 • I i :
I,
] , ; 1 1 I j i l i
; I I 1 I
i � ; 1 1 1 1 I I i I
i i 1 1
i I i ;
I j i l i
i
1
:
i'
0.08 ___— - -__ _ _ __
l i
i j : I : . I i
1 j! . 1 j 1
- -1 I 1 j i i i j ; .
I
i i
d j :
• M 6 .
_ 0.10 I I 1 I I 1 1 1 11 I I I I 1 I I I I I I 1 I I I
O
N 1 00 200 500 1,000 2,000 5,000 10,000 20,000 50,000 100,000
, T PRESSURE (pounds per square foot)
co
` o
el
v SAMPLE
BORING DEPTH SOIL MOISTURE DRY DENSITY
E KEY NUMBER (FEET) CLASSIFICATION CONTENT (pcf) 3
U
F • TP -2 4 - 6 Brown silt with trace fine sand (ML) 32.8% 87
0
r ., ,
N
6 CONSOLIDATION TEST RESULTS
Li 9 _
q Geo Eng Yl eers
\∎/ FIGURE A -22
N
j •
1 1