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RECEIVE:D
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DEVELOPMENT SERVICES CTF1.
CITY OF EOM01VOS
Geotechnical Engineering Report
Meadowdale Estates
Edmonds, Washington
For
Hoover Premier Homes
R cEguED
JUL 0 g 2006
-EECE
January 6, 2005
Ms. Cathy Patterson
Hoover Premier Homes
16300 Mill Creek Boulevard, ##108
Mill Creek, WA 98012
Geotechnical Engineering Report
Meadowdale Estates
Edmonds, Washington
CG File No. 1791
Dear Ms. Patterson:
17625 -130th Ave. NE, 0102, Woodinville, WA 98072
Phone: 425.6441977
Fax: 425-844-1987
INTRODUCTION
This report presents the results of our geotechnical engineering investigation for your Meadowdale
_. Estates residential development in the Meadowdale area of Edmonds, Washington. The site is located at
6880-172 nd Street SW, as shown on the Vicinity Map in Figure 1.
Site development, including grading, road construction; and utility placement, has been substantially
completed. We understand that you have purchased all of the building lots, with the exception of Lot 2,
for the purposes of constructing single-family residences. The City of Edmonds has required a
geotechnical report for the lots with slopes greater than 15 percent, and you have requested that we
evaluate the subsurface conditions of your lots and provide foundation recommendations for the proposed
residences. For our use in preparing this report, we have been provided with a copy of a site plan by CHS
Engineering, dated September 2003, that shows lot, road, and utility layout. We have also been provided
with a Slope Stability Evaluation, prepared by GeoEngineers and dated rune 1.8, 2002, that addresses the
detention facility. Additionally, we have been provided with field reports prepared by Sky Valley Testing
that document compaction testing performed during the main earthwork phase of the project.
PROJECT DESCRIPTION
The L-shaped project site has maximum dimensions of approximately 640 feet north to south and 440 feet
east to west. The development consists of a total of 12 lots. We understand that you intend to construct
Geotechnical Engineering Report
Meadowdaie Estates
Edmonds, Washington
January 6, 2005
CG File No. 1791
Page 2
single-family residences on all of the lots with the exception of Lot 2, which you do not own. The
provided grading plan indicates cuts totaling 6,000 cubic yards (CY) and fills totaling 12,000 CY. The
grading plan also indicates that fills may be at least 12 feet deep in some areas. At this point in time, site
grading has been completed and utilities have been installed. A completed storm water detention vault is
located close to the western site boundary.
rt SCOPE
v_ The purpose of this study is to explore and characterize the subsurface conditions and present
recommendations for site development. Specifically, our scope of services as outlined in our Services
Agreement, dated December 23, 2004, includes the following:
1. Review available geologic maps of the area and available project documentation.
2. Explore the subsurface conditions at the site with backhoe -excavated test pits.
3. Provide recommendations for building -foundations, including lateral pressures for
retaining walls.
4. Provide recommendations for site preparation and grading.
5. Provide general recommendations for site drainage.
6. Prepare a written report to document our conclusions and recommendations.
SITE CONDITIONS
Surface Conditions
At the time of our exploration, the access road (69`l Place W) was paved. Site grading was also complete
and grass was growing on all of the lots. The storm water detention vault and utilities had all been
completed, but no residences had been constructed yet. A layout of the site is shown on the Site Plan in
Figure 2.
Generally, the ground surface slopes downward towards the west at approximately 3 Horizontal to I
Vertical (3H:1V). An existing residence borders the southwestern corner of the site and 172nd Street SW
borders the site to the south. The rest of the site is surrounded by a wooded area with brush and evergreen
trees up to approximately 2 feet in diameter.
Cornerstone Geotechnical, Inc.
Geotechnical Engineering Report
Meadowdale Estates
Edmonds, Washington
January 6, 2005
CG File No. 1791
Page 3
Geology
Most of the Puget Sound Region was affected by past intrusion of continental glaciation. The last period
of glaciation, the Vashon Stade of the Fraser Glaciation, ended approximately 11,000 years ago. Many of
the geomorphic features seen today are a result of scouring and overriding by glacial ice. During the
Vashon Stade, much of the Puget Sound region was overridden by over 3,000 feet of ice. Soil layers
overridden by the ice sheet were compacted to a much greater extent than those that were not. Part of a
typical glacial sequence includes recessional outwash sand underlain by glacial till.
The site is mapped as being underlain by glacial till (Preliminary Sur ficial Geologic Map of the Edmonds
East and Edmonds West adran les Snohomish and King Counties, Mackey Smith, 1975). The map
also indicates the presence of advance and recessional outwash in the general area surrounding the site.
Our site explorations encountered glacial till, recessional outwash, and fill. Glacial till, commonly
referred to as "hardpan," is an unsorted mixture of sand, silt, and gravel that is deposited at the bottom of
a continental glacier. As a result of having been consolidated under the weight of the glacier, glacial till
exhibits both high strength and low permeability. Alluvial sand and gravel deposited by glacial melt
water during glacial recession is known as recessional outwash. In contrast to glacial till, recessional
outwash has not been glacially consolidated.
Explorations
Subsurface conditions were explored at the site on December 28, 2004, by excavating a total of five test
pits. The test pits were excavated to depths ranging between 0.5 and 11.0 feet below the ground surface.
The explorations were located'in the field by a representative from this firm who also examined the soils
and geologic conditions encountered, and maintained logs of the test pits. The approximate locations of
the test pits are shown on the Site Plan in Figure 2: The soils were visually classified in general
accordance with the Unified Soil Classification System, a copy of which is presented as Figure 3. The
r'" logs of the test pits are presented in Figures 4 and 5.
1.. -
Subsurface Conditions
A brief description of the conditions encountered in our explorations is included below. For a more
detailed description of the soils encountered, review the test pit logs in Figures 4 and 5.
Cornerstone Geotechnical, Inc.
Geotechnical Engineering Report
1Vleadowdale Estates
Edmonds, Washington
January 6, 2005
CG File No. 1791
Page 4
Our explorations encountered. glacial till, recessional outwash, and fill. Test Pits 3, 4 and 5 were
excavated in cut areas and all encounteredvery dense till within one foot of the surface. Test Pits 1 and 2
encountered approximately 4.0 and 5.0 feet of fill, respectively. Beneath the fill, Test Pit 1 encountered
recessional outwash. Test Pit 2 encountered a layer of topsoil underlying the fill. The topsoil layer was
underlain by weathered glacial till becoming glacial till. It should be noted that loose soils in the areas of
Test Pits 1 and 2 extend at least 4.0 and 6.0 feet below the ground surface, respectively.
Hydrologic Conditions
r Shallow ground water seepage was encountered in Test Pit 2 at a depth .of approximately 1.0 foot. We
consider this water to be perched, and associated with surface runoff. The on-site till, in particular, is
considered poorly draining. During the wetter times of the year, we expect perched water conditions will
occur as pockets of water on top of the till layer. Perched water does not represent a regional ground
water "table" within the upper soil horizons. Volumes of perched ground water vary depending upon the
time of year and the upslope recharge conditions.
Erosion Hazard
The erosion hazard criteria used for determination of affected areas includes soil type, slope gradient,
vegetation cover, and ground water conditions. The erosion sensitivity is related to vegetative cover and
the specific surface soil types (group classification), which are related to the underlying geologic soil
units. The Soil Survey of Snohomish County Area Washington by the Soil Conservation Service (SCS)
was reviewed to determine the erosion hazard of the on-site soils. The site surface soils were classified
using the SCS classification system as Unit 5 (Alderwood — Urban Land Complex). The corresponding
geologic unit for these soils is till, which is generally in agreement with the soils encountered in our site
explorations. The erosion hazard for the soil is listed as being slight for slopes less than 8 percent. The
moderately -sloping portions of the site may encounter higher levels of erosion, but not to such a degree
that the site would be classified an erosion hazard. Best management practices (BMPs) and applicable
codes should be followed during site grading to limit potential for erosion. We do not expect this site will
require unusual or extreme erosion management methods. There are no water bodies adjacent to the site.
Cornerstone Geotechnical, Inc.
Geotechnical Engineering Report
Meadowdale Estates
Edmonds, Washington
January 6, 2005
CG File No. 1791
Page 5
Seismic Hazard -
The site is classified based on its overall soil profile using Table 1615.1.1 of the 2003 International
Building Code (TBC). Site conditions best fit the IBC definition for Site Class C ("Very dense soil and
soft rock"). The IBC provides parameters and coefficients to be used in seismic design based upon this
site class.
Additional seismic considerations include liquefaction potential and amplification of ground motions by
soft soil deposits. The liquefaction potential is highest for loose sand with a high ground water table. The
underlying dense till is considered to have a .very low potential for liquefaction and amplification of
ground motion.
CONCLUSIONS AND RECOMMENDATIONS
General
It is our opinion that the site is compatible with the planned development_ The underlying medium dense
to very dense glacial till deposits are capable of supporting the planned structures and pavements. We
recommend that the foundations for the structures extend through any topsoil, fill, loose, or disturbed
soils, and bear on the underlying medium dense to very dense, native glacial till, or on structural fill .
extending to these soils. Based on our explorations, we anticipate these soils will generally be
encountered at typical footing depths in the cut areas of the site. Fill encountered in Test Pits 1 and 2 .was
loose. As a result, areas of fill may need to be over -excavated and properly compacted. Alternatively,
foundations could be constructed to extend through the loose soils.
The soils likely to be exposed during construction are highly moisture sensitive and will disturb easily
when wet or during wet conditions. We recommend that construction take place during the drier summer
months, if possible. If construction takes place during the wet season, additional expenses and delays
should be expected due to the wet conditions.
Site Preparations and Grading
The first step of site preparation should be to strip the vegetation, topsoil, or loose soils to expose medium
dense to very dense native soils in pavement and building areas. This material should be removed from
the site, or stockpiled for later use as landscaping fill. The resulting subgrade should be compacted to a
Cornerstone Geotechnical, Inc.
Geotechnical Engineering Report
Meadowdale Estates
Edmonds, Washington
January 6, 2005
CG File No. 1791
Page 6
firm, non -yielding condition. Areas observed to pump or weave should be repaired prior to placing hard
surfaces.
The on-site glacial till likely to be exposed during construction is considered highly moisture sensitive,
and the surface will disturb easily when wet. We expect these soils would be difficult, if not impossible,
to compact to structural fill specifications in wet weather. We recommend that earthwork be conducted
during the drier months. Additional expenses of wet weather or winter construction would include extra
excavation and use of imported fill or rock spalls.
Structural Fill
General: All fill placed beneath buildings, pavements or other settlement sensitive features should be
placed as structural fill. Structural fill, by definition, is placed in accordance with prescribed methods and
standards, and is monitored by an experienced geotechnical professional or soils technician. Field -
monitoring procedures would include the performance of a representative number of in-place density tests
to document the attainment of the desired degree of relative compaction.
Materials: Imported structural fill should consist of a good quality, free -draining granular soil, free of
organics and other deleterious material, and be well graded to a maximum size of about 3 inches.
Imported, all-weather structural fill should contain no more than 5 percent fines (soil finer than a Standard
U.S. No. 200 sieve), based on that fraction passing the U -S. 314 -inch sieve.
The use of on-site soil as structural fill will be dependent on moisture content control. Some drying of the
native soils may be necessary in order to achieve compaction_ During warni, sunny days this could be
accomplished by spreading the material in thin lifts and compacting. Some aeration and/or addition of
moisture may also be necessary. We expect that compaction of the native soils to structural fill
specifications would be difficult, if not impossible, during wet weather.
Fill PIacement: Following subgrade preparation, placement of the structural fill may proceed_ Fill
should be placed in 8- to 10 -inch -thick uniform lifts, and each lift should be spread evenly and be
thoroughly compacted prior to placement of subsequent lifts. All structural fill underlying building areas,
and within a depth of 2 feet below pavement and sidewalk subgrade, should be compacted to at least 95
percent of its maximum dry density. Maximum dry density, in this report, refers to that density as
Cornerstone Geotechnical, Inc.
-Geotechnical Engineering Report
Meadowdale Estates
Edmonds, Washington
January 6, 2005
CG File No. 1791
Page 7
determined by the ASTM D 1557 compaction. test procedure. Fill more than 2 feet beneath sidewalks and
pavement subgrades should be compacted to at least 90 percent of the maximum dry density. The
moisture content of the soil to be compacted should be within about 2 percent of optimum so that a
readily compactable condition exists. It may be necessary to over excavate and remove wet surficial soils
in cases where drying to a compactable condition is not feasible. All compaction should be accomplished
by equipment of a type and size sufficient to attain the desired degree of compaction.
Temporary and Permanent Slopes
._._ Temporary cut slope stability is a function of many factors, such as the type and consistency of soils,
depth of the cut, surcharge loads adjacent to the excavation, length of time a cut remains open, and the
presence of surface or ground water. It is exceedingly difficult under these variable conditions to estimate
a stable temporary cut slope geometry. Therefore, it should be the responsibility of the contractor to
maintain safe slope configurations, since the contractor is continuously at the job site, able to observe the
nature and condition of the cut slopes, and able to monitor the subsurface materials and ground water
— conditions encountered.
We anticipate cuts for the daylight basements of your proposed residences. For planning purposes, we
recommend that temporary cuts in the near -surface weathered soils be no greater than 1111 V. Cuts in the
fill should be no greater than 1.5HAV. Cuts in the dense to very dense till may stand at a 0.75H:IV
inclination or possibly steeper. If ground water seepage is encountered, we would expect that flatter
inclinations would be necessary.
We recommend that cut slopes be protected from erosion. Measures taken may include covering cut
slopes with plastic sheeting and diverting surface runoff away from the top of cut slopes. We do not
recommend vertical slopes for cuts deeper than 4 feet, if worker access is necessary. We recommend that
cut slope heights and inclinations conform to local and WISHA/OSHA standards.
Final slope inclinations for structural fill and the cuts in the native soils should be no steeper than 2H: IV.
Lightly compacted fills or common fills should be no steeper than 3H: I V. Common fills are defined as
fill material with some organics that are "trackrolled" into place. They would not meet the compaction
specification of structural fill. Final slopes should be vegetated and covered with straw or jute netting.
The vegetation should be maintained until it is established.
Cornerstone Geotechnical, Inc.
-Geotechnical Engineering Report
Meadowdale Estates
Edmonds, Washington
January 6, 2005
CG File No. 1791
Page 8
Foundations
Conventional shallow spread foundations should be founded on undisturbed, medium dense to very
dense, glacial till, or be supported on structural fill extending to those soils. If the soil at the planned
bottom of footing elevation is not medium dense to very dense, it should be overexcavated to expose
suitable bearing soil, and the excavation should be filled with structural fill, or the footing may be
overpoured with extra concrete. For residences planned to be built on sloping ground, we recommend a
minimum horizontal distance of 10 feet between the bottom of the footing and the slope face.
Footings should extend at least 18 inches below the lowest adjacent finished ground surface for..frost
protection and bearing capacity considerations. Minimum foundation widths of 16 and 20 inches should
be used for continuous and isolated spread footings, respectively. Standing water should not be allowed
to accumulate in footing trenches. All loose or disturbed soil should be removed from the foundation
excavation prior to placing concrete.
For foundations constructed as outlined above, we recommend an allowable design bearing pressure of
2,000 pounds per square foot (psf) be used for the footing design_ International Building Code (IBC)
guidelines should be followed when considering short-term transitory wind or seismic loads. Potential
foundation settlement using the recommended allowable bearing pressure is estimated to be less than f-
inch total and %-inch differential between footings or across a distance of about 30 feet. Higher soil
bearing values may be appropriate for footings founded on the unweathered till, and with wider footings:
These higher values can be determined after a review of a specific design.
Lateral loads can be resisted by friction between the foundation and subgrade soil, and by passive soil
resistance acting on the below -grade portion of the foundation. For the latter, the foundation must be
poured "neat" against undisturbed soil or backfilled with clean, free -draining, compacted structural fill.
Passive resistance may be calculated as a triangular equivalent fluid pressure distribution. We
recommend that an equivalent fluid density of 225 pounds per cubic foot (pcf) be used to calculate the
allowable lateral passive resistance for the case of a level ground surface adjacent to the footing. An
allowable coefficient of friction between footings and soil of 0.45 may be used, and should be applied to
the vertical dead load only. A factor of safety of 2.0 has been applied to the passive pressure to account
for required movements to generate these pressures_ The friction coefficient does not include a factor of
safety_
Cornerstone Geotechnical, Inc.
-Geotechnical Engineering Report
Meadowdale Estates
Edmonds, Washington
January 6, 2005
CG File No. 1791
Page 9
Lateral Loads
The lateral earth pressure acting on retaining walls is dependent on the nature and density of the soil
behind the wall, the amount of lateral wall movement that can occur as backfill is placed, and the
inclination of the backfill. Walls that are free to yield at least one -thousandth of the height of the wall are
in an "active" condition. Walls restrained from movement by stiffness or bracing are in an "at -rest"
condition. Active earth pressure and at -rest earth pressure can be calculated based on equivalent fluid
density. Equivalent fluid densities for active and at -rest earth pressure of 35 pounds per cubic foot (pcf)
and 55 pcf, respectively, may be used for design for a level backslope. Equivalent fluid densities for
active and at -rest earth pressure of 45 pounds per cubic foot (pcf) and 75 pcf, respectively, may be used
for design for a 20 degree backslope. These values assume that the on-site soils are used for backfill,
and that the wall backfill is drained. The preceding values do not include the effects of surcharges due to
foundation loads, traffic or other surface loads. Surcharge effects should be considered where
appropriate.
The above lateral pressures may be resisted by friction at the base of the wall and passive resistance
against the foundation. A coefficient of friction of 0.45 may be used to determine the base friction when
supported on the above recommended foundation subgradc preparation alternatives. An equivalent fluid
density of 225 pcf should be used for passive resistance. The friction value does not incorporate a safety
factor. A safety factor of 2 is applied to the passive pressure to limit movement.
All wall backfill should be well compacted. Care should be taken to prevent the buildup of excess lateral
soil pressures due to overcompaction of the wall backfill. This can be accomplished by placing wall
backfill in 8 -inch loose lifts and compacting with small, hand -operated compactors.
Slabs -On -Grade
Slab -on -grade areas should be prepared as recommended in the Site Preparation and Grading
subsection. Slabs should be supported on medium dense to very dense native soils, or on structural fill
extending to these soils. Where moisture control is a concern, we recommend that slabs be underlain by 6
inches of free -draining coarse sand or pea gravel for use as a capillary break. A suitable vapor barrier,
such as heavy plastic sheeting, should be placed over the capillary break.
Cornerstone Geotechnical, Inc.
Geotechnical Engineering Report
'Meadowdale Estates
Edmonds, Washington
January 6, 2005
CG File No. 1791
Page 10
Drainage
We recommend that runoff from impervious surfaces, such as roofs, driveway and access roadways, be
collected and routed to an appropriate storm water discharge system. Final site grades should allow for
drainage away from any buildings. We suggest that the finished ground surface be sloped at a gradient of
3 percent minimum, for a distance of at least 10 feet away from the buildings. Surface water should be
collected by permanent catch basins and drain lines, and be discharged into a storm drain system.
We recommend that footing drains be used around all of the structures where moisture control is
important. The underlying till will pond water that accumulates in the crawl space. It is good practice to
use footing drains installed at least 1 foot below the planned finished floor slab or crawl space elevation to
provide drainage for the crawl space. At a minimum, the crawl space should be sloped to drain to an
outlet tied to the drainage system_ If drains are omitted around slab -on -grade floors where moisture
control is important, the slab should be a minimum of 1 foot above surrounding grades.
Where used, footing drains should consist of 4 -inch -diameter, perforated PVC pipe that is surrounded by
free -draining material, such as pea gravel. Footing drains should discharge into tightlines leading to an
appropriate collection and discharge point. Crawl spaces should be sloped to drain, and a positive
connection should be made into the foundation .drainage system. For slabs -on -grade, a drainage path
should be provided from the capillary break material to the footing drain system. Roof drains should not
be connected to wall or footing drains.
MONITORING
We should be retained to provide monitoring and consultation services during construction to confirm that
the conditions encountered are consistent with those indicated by the explorations, and to provide
recommendations for design changes, should the conditions revealed during the work differ from those
anticipated.
USE OF THIS REPORT
We have prepared this report for Hoover Premier Homes and their agents, for use in planning and design
of this project. The data and report should be provided to prospective contractors for their bidding and
Cornerstone Geotechnical, Inc.
Geotechnical Engineering Report
Meadowdale Estates
Edmonds, Washington
January b, 2005
CG File No. 1791
T Page 11
estimating purposes, but our report, conclusions and interpretations should not be construed as a warranty
of subsurface conditions.
The scope of our work does not include. services related to construction safety precautions, and our
recommendations are not intended to direct the contractors' methods, techniques, sequences or
procedures, except as specifically described in our report, for consideration in design. There are possible
�.= variations in subsurface conditions. We recommend that project planning include contingencies in budget
and schedule, should areas be found with conditions that vary from those described in this report.
Within the limitations of scope, schedule and budget for our work, we have strived to take care that our
work has been completed in accordance with generally accepted practices followed in this area at the time
this report was prepared. No other conditions, expressed or implied, should be understood.
000
Cornerstone Geotechnical, Inc.
Geotechnical Engineering Report
'Meadowdale Estates
Edmonds, Washington
January 6, 2005
CG File No. 1791
Page 12
We appreciate the opportunity to be of service to you. If there are any questions concerning this report or
if we can provide additional services, please call.
Sincerely,
Cornerstone Geotechnical; Inc.
Jeff Laub, LG
Project Geologist
EXPI tES 081161,91 -
Rick B. Powell, PE
Principal
PAO:JPL:RBP:nt
Three Copies Submitted
Five Figures
Cornerstone Geotechnical, Inc.
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Cornerstone Phone: (425) 844-1977
RH Hoover - Meadowdale Estates
Fax: (425) 844-1987
Geotechnical, Inc.
File Number
Figure
17625 -130th Ave NE, C-102 - Woodinville, WA - 98072
1791
1
Unified Soil Classification System
MAJOR DIVISIONS
GROUP GROUP NAME
SYMBOL.
GRAVEL CLEAN GRAVEL
COARSE-
GW WELL -GRADED GRAVEL, FINE TO COARSE GRAVEL
GRAINED MORE THAN 50% OF
GP POORLY -GRADED GRAVEL
COARSE FRACTION
SOILS RETAINED ON NO.4 GRAVEL
SIEVE
WIN { FINES
GM SILTY GRAVEL
GC CLAYEY GRAVEL
MORE THAN 50%
RETAINED ON SAND CLEAN SAND
number 2000 SIEVE
SW WELL -GRADED SAND, FINE TO COARSE SAND
MORE THAN 50% OF
SP POORLY -GRADED SAND
COARSE FRACTION SAND
i:..-..
PASSES NO.4 SIEVE
WITH FINES
SM SILTY SAND
SC CLAYEY SAND
SILT AND CLAY INORGANIC
FINE -
ML SILT
GRAINED LIQUID LIMIT
LESS THAN 50%
CL CLAY
SOILS ORGANIC
OL ORGANIC SILT, ORGANIC CLAY
-
MORETHAN50% SILTAND CLAY
PASSES NO. 200 SIEVE INORGANIC
MH SILT OF HIGH PLASTICITY, ELASTIC SILT
LIQUID LIMIT
50% OR MORE
CH CLAY OF HIGH PLASTICITY, FAT CLAY
ORGANIC
OH ORGANIC CLAY, ORGANIC SILT
HIGHLY ORGANIC. SOILS
PT PIAT
NOTES:
SOIL MOISTURE MODIFIERS
1) Field classification is based on
Dry -Absence of moisture, dusty, dry
Visual examination of soil in general
accordance with ASTM D 2488-83.
to the touch
2) Soil classification using laboratory
Moist- Damp, but no visible water
tests is based on ASTM D 2487-83.
Wet- Visible free water or saturated,
3) Descriptions of soil density or
usually soil is obtained from
consistency are based on
below water table
interpretation of blowcount data,
visual appearance of soils, and/or
test data.
Cornerstone Phone: (425)844-1977 Unified Soil Classification System
Geotechnical, Inc. F (425)8443987
.0
17625 -130th Ave NE, C-102 • Woodinville, WA* 98072 Figure 3
CORNERSTONE GEOTECHNICAL, INC.
FILE NO 1791
FIGURE 4
LOG OF EXPLORATION
€ ' . DEPTH
USC
SOIL DESCRIPTION
- TEST PIT ONE
0.0-3.0
SM
GRAY -BROWN SILTY FINE TO COARSE SAND WITH GRAVEL (LOOSE, MOIST) (FILL)
3.0-4.0
SM
DARK -GRAY SILTY FINE TO COARSE SAND WITH TRACE GRAVEL AND ORGANICS
(LOOSE, WET) (FILL)
4.0-10.0
SM
GRAY SILTY MEDIUM TO COARSE SAND WITH GRAVEL (LOOSE TO MEDIUM DENSE,
WET) (RECESSIONAL OUTWASHIFILL?)
SAMPLES WERE COLLECTED AT 3.5, 8.0 AND 10.0 FEET
GROUND WATER SEEPAGE WAS NOT ENCOUNTERED
TEST PIT CAVING WAS ENCOUNTERED BETWEEN 0.0 AND 4.0 FEET
TEST PIT WAS COMPLETED AT 10.0 FEET ON 12!28104
TEST PIT TWO
0.0-1.0
SM
DARK BROWN TO BLACK SILTY SAND WITH GRAVEL (LOOSE, WET) (TOPSOILIDUFF)
1.0-5.0
SM
GRAY -BROWN SILTY FINE TO COARSE SAND WITH GRAVEL (LOOSE, WET) (FILL)
5.0-6.0
SM
DARK BROWN TO BLACK SILTY SAND WITH GRAVEL AND ORGANICS (LOOSE, WET)
(TOPSOIL)
6.0-10.0
SM
RED -BROWN SILTY FINE TO MEDIUM SAND WITH GRAVEL AND ROOTS (LOOSE TO
MEDIUM DENSE; MOIST) (WEATHERED TILL)
10.0-11.0
SM
BROWN -GRAY SILTY FINE TO MEDIUM SAND WITH GRAVEL (DENSE, MOIST) (TILL)
SAMPLES WERE COLLECTED AT 3.0, 5.0, 9.0 AND 11.0 FEET
GROUND WATER SEEPAGE WAS ENCOUNTERED AT APPROXIMATELY 1.0 FEET
SLIGHT TEST PIT CAVING WAS ENCOUNTERED BETWEEN 0.0 AND 6.0 FEET
TEST PIT WAS COMPLETED AT 11.0 FEET ON 12/28!04
TEST PIT THREE
0.0-1.0
SM
BROWN SILTY FINE TO MEDIUM SAND WITH GRAVEL (LOOSE, MOIST) (FILL)
1.0-4.0
SM
GRAY SILTY FINE TO MEDIUM SAND WITH GRAVEL (VERY DENSE, MOIST) (TILL)
SAMPLE WAS COLLECTED AT 4.0 FEET
GROUND WATER SEEPAGE WAS NOT ENCOUNTERED
TEST PIT CAVING WAS NOT ENCOUNTERED
TEST PIT WAS COMPLETED AT 4.0 FEET ON 12/28/04
TEST PIT FOUR
0.0-0-5
SM
GRAY SILTY FINE TO MEDIUM SAND WITH GRAVEL (VERY DENSE, MOIST) (TILL)
NO SAMPLE WAS COLLECTED
GROUND WATER SEEPAGE WAS NOT ENCOUNTERED
TEST PIT CAVING WAS NOT ENCOUNTERED
TEST PIT WAS COMPLETED AT 0.5 FEET ON 12/28/04
CORNERSTONE GEOTECHNICAL, INC.
FILE NO 1791
FIGURE 4
LOG OF EXPLORATION
DEPTH USC SOIL DESCRIPTION
TEST PIT FIVE
0.0--1.0 SM BROWN SILTY FINE TO MEDIUM SAND WITH GRAVEL (LOOSE, MOIST) (FILL)
1.0-1.5 SM GRAY SILTY FINE TO MEDIUM SAND WITH GRAVEL (VERY DENSE, MOIST) (TILL)
NO SAMPLE WAS COLLECTED
GROUND WATER SEEPAGE WAS NOT ENCOUNTERED
TEST PIT CAVING WAS NOT ENCOUNTERED
TEST PIT WAS COMPLETED AT 9.5 FEET ON 92/28/04
CORNERSTONE GEOTECHNICAL, INC.
FILE NO 1791
FIGURE 5