zorchenkogeo.pdfGEOTECHNICAL ENGINEERING STUDY
PROPOSED SINGLE FAMILY RESIDENCE
8910 -178" PLACE SW
EDMONDS, WASHINGTON
Project No. G-2310
Prepared for
Mr. Aleksey Zorchenko
30510 - 25"i Place SW
Federal Way, WA 98023
August 7, 2006
GEO GROUP NORTHWEST, INC.
13244 NE 20"' Street, Suite 10
Bellevue, Washington 98005
Phone: (425) 649-8757
sts
Group Northwest, nc. Geoiech&Environmental cienti
Ists
August 7, 2006
Mr. Aleksey Zorchenko
30510 - 25' Place SW
Federal Way, WA 98023
Subject: GEOTECHNICAL ENGINEERING STUDY
Proposed Single Family Residence
8910 - 178' Place SW
Edmonds, Washington
Dear Mr. Zorchenko:
Project No. G-2310
GEO Group Northwest conducted a geotechnical engineering study for the vacant lot at 8910 -
178"' Place SW in Edmonds, Washington. The project site location is shown on the Vicinity
Map, Plate 1. We understand that the lot will be developed with a single family home. Site
development plans were not provided for our review.
The scope of work performed for this study included a visual reconnaissance of the site, review
of the area geologic map, evaluation of the subsurface conditions by excavating three test pits
with a trackhoe, probing of the soils as the test pits were being excavated, collection of soil
samples, analysis of the soil samples for moisture content, preparation of test pit logs,
engineering analysis, and preparation of this report of our findings, conclusions, and
geotechnical recommendations addressing constructing a new home on the lot.
SITE CONDITIONS AND SITE DESCRIPTION
The subject lot (Tax Parcel 00914200001500) is approximately 0.46 acres in size according to
Snohomish County parcel records. The lot is irregular in shape, as illustrated on the Site Plan,
Plate 2. The lot is bordered by 178`'' Place SW to the north and residential properties to the west,
south, and east. The western half of the lot was cleared and the eastern half vegetated with
13240 NE 20th Street, Suite 10 • Bellevue, Washington 98005
Phone 4251649-8757 • FAX 425/649-8758
August 7, 2006
Geotechnical Study
8910 - 178" Place SW, Edmonds, WA
G-2310
Page 2
blackberry vines, brush and two fir trees. A topographic site plan was not available at the time
this report was prepared. Based on our visual observations, the lot generally slopes up to the
south and east, with the eastern portion of the property about 8 feet higher than the west end. A
steep road -cut embankment exists adjacent to 1781h Place SW at the east end of the lot.
SUBSURFACE CONDITIONS
According to the "Geologic Map of the Edmonds East & Part of the Edmonds West
Quadrangles, Washington" by James P. Minard, dated 1983, the project site is located near the
mapped contact between Transitional Beds (Qtb) and Recessional Outwash (Qvr). Transitional
beds are described as consisting of interglacial deposits of silt and clay interbedded with sand
lenses. Recessional Outwash generally consists of fluvial sand and gravel deposits that were
deposited as the glaciers retreated some 12,000 years ago.
We investigated the subsurface_ site conditions by observing the excavation of three test pits with
a trackhoe excavator. The depth of the test pits ranged from 7 to 10.2 feet. The location of the
test pits are illustrated on the Site Plan, Plate 2. The following describes the soils encountered
at the test pit locations. The soils encountered and their thicknesses may be different at other
locations on the lot.
TP -1
Test Pit TP -1, located at the upper east end of the lot, encountered a thin layer of topsoil
underlain by medium dense to dense Sand with gravel and some silt to a depth of about 4
feet. Below 4 feet the soils consisted of very dense gravelly Sand to the total depth of the
test pit at 7 feet.
TP -2
Test Pit TP -2, located in the middle of the lot, encountered dense to medium dense silty Sand
(Fill) to a depth of 3 feet, underlain by loose gravelly Sand (Fill) and a thin layer of topsoil to
a depth of about 5 feet. Below the fill and topsoil layer the soils consisted of dense, red-
GEO Group Northwest, Inc.
August 7, 2006
Geotechnical Study
8910 - 178`h Place SW, Edmonds, WA
G-2310
Page 3
brown, gravelly Sand with some silt to a depth of about 7.8 feet underlain by dense, red -
brown silty Sand with gravel to the total depth of the test pit at 9 feet.
TP -3
Test Pit TP -3, located in the western portion of the lot, encountered about 3 feet of dense
silty Sand with gravel (Fill) underlain by a loose mixture of dark brown silty Sand and gray
sandy Silt (Fill) to a depth of about 5.3 feet. Below 5.3 feet the soils consisted of very moist,
loose to medium dense, silty Sand with gravel to a depth of 10 feet. At 10 feet very stiff to
hard Clay was encountered,
No groundwater seepage was encountered in the test pits, but the soils were very moist below the
fill in TP -3. Groundwater and seepage conditions may vary depending on the time of year and
amount of prior precipitation.
It appears that the fill soils were used level the western half of the lot where a former depression
or swale was located. The sand and gravel soils encountered in TP -1 and below the fill in TP -2
are interpreted to be Recessional Qutwash (Qvr) material. The clay encountered at a depth of 10
feet in TP -3 is interpreted to be Transitional Beds (Qtb), as indicated on the geologic map.
SEISMIC CONSIDERATIONS
Based on the soil conditions encountered, the site is seismically classified as Site Class C (very
dense soil), in accordance with Table 1615.1.1 of the 2003 International Building Code (IBC).
Slopes on the site appear to be stable. No signs of slope instability were observed, such as
tension cracks, slumps, slides, or scarps. The embankment at the east end of the lot, adjacent to
178'hPlace SW, is a man-made road cut. The potential for liquefaction and/or lateral spreading
is very low due to the presence of dense soils and a lack of shallow groundwater at the project
site. No known faults intersect the subject property and in our opinion the risk of surface rupture
is low as a result of a large magnitude seismic event. No structural mitigation measures are
recommended.
GEo Group Northwest, Inc.
August 7, 2006
Geotechnical Study
8910 - 178"' Place SW, Edmonds, WA
DISCUSSIONS AND RECOMMENDATIONS
G-2310
Page 4
In general; the layer of fill material, up to 5.3 feet thick, was encountered in the middle and
western portions of the site. The upper portion of the fill is generally dense and the bottom
portion Ioose. The upper portion appears to be suitable for supporting a driveway, but should not
used to support the house. The dense soils that underlie the loose fill are suitable for supporting
a residential structure.
Based on the results of this study, it is our professional opinion that the site is geotechnically
suitable for development with a single family residence. The new home can be supported on a
conventional spread footing foundation provided the footings extend down to the dense site soils.
Where loose fill soils are present, the loose fill should be removed. If loose to medium dense
soils underlie the fill, those soils should be compacted (western portion of lot) and a 2 foot thick
crushed rock pad placed on the compacted base soils. Spread footings may be supported on the
crushed rock pad or on structural fill placed above the crushed rock in order to bring the
subgrade back up to the desired footing elevation, as discussed in the Foundations section of this
report. The structural fill should be compacted to 95% of the material's maximum dry density as
discussed in the Structural Fill section of this report.
Near the existing embankment along 1781h Place -SW, the bottom of the footings should extend
below a 1H:1V line (plane) projected up from base of the embankment.
The main geotechnical issues for the project include erosion control, site preparation, temporary
and permanent cuts and fills, foundation subgrade preparation, foundation soil bearing design
criteria, basement and retaining wall design criteria, slab -on -grade floor subgrade preparation
and capillary break recommendations, subsurface drainage, and drive subgrade preparation and
recommendations.
GEo Group Northwest, Inc.
August 7, 2006 G-2310
Geotechnical Study Page 5
8910 - 178"` Place SW, Edmonds, WA
SITE PREPARATION AND GENERAL EARTHWORK
Erosion Control
Silt fencing should be installed below the construction area to prevent sediment laden water from
leaving the site. The bottom of the silt fence should be buried and washed gravel placed against
the base. During wet weather, temporary detention of storm water may be needed, exposed soil
should be protected with straw mulch, and cut slopes protected with plastic sheeting. A crushed
rock construction entrance should be used to mitigate tracking of mud onto the street.
Certs and Fills
Under no circumstances should temporary excavation slopes be greater than the limits specified
in local, state and national government safety regulations. It is the responsibility of the
contractor to provide a safe work environment. Temporary cuts greater than four feet in height
should be sloped at an inclination no steeper than 1H:1V (Horizontal:Vertical) in loose to
medium dense soils. Steeper temporary cuts up to 1H:2V may be feasible in the dense site soils,
provided the stability of the soils are evaluated by the geotechnical engineer at the time of
excavation and the cuts are protected from weather. The stability of temporary cuts should be
evaluated by the geotechnical engineer if groundwater seepage is encountered. Temporary cuts
should not encroach onto the neighboring properties. if the temporary open cut excavations are
not feasible due to property line or other constraints then temporary shoring may be required.
Permanent cut and fill slopes should be inclined no steeper than 2H:1 V. Permanent 2H:1 V fill
slopes should be compacted to a minimum of 90 percent of the material's maximum dry density.
Permanent slopes of 3H:1V, or less, are recommended if they are to be mowed and maintained.
Once the site development plans are finalized, GEO Group Northwest should provide
geotechnical design criteria recommendations for proposed site development features not
specifically addressed in this report.
Go Group Northwest, Inc.
August 7, 2006
Geotechnical Study
8910 - 178' Place SW, Edmonds, WA
Structural Fill
G-2310
Page 6
Structural fill is defined as compacted engineered fill soils used to support building foundation
loads, floor slabs, patios, porches, retaining walls, sidewalks, and pavements. In general, soils
containing silt are moisture sensitive and can be difficult to compact to structural fill compaction
specifications depending on the material's moisture content and the time of year that
construction takes place. Silty site soils are not recommended to be used as structural fill during
wet weather unless they are amended by treatment with Portland cement. Soils containing
organics, debris and/or rubble, should not be used as structural fill.
Structural fill should be placed at the material's optimum moisture content and compacted in 10 -
inch thick lifts, or less. Under building.foundations and slab -on -grade floors, structural fill
should be compacted to a minimum of 95 percent of the material's maximum dry density, as
determined by ASTM Test Designation D-1557 (Modified Proctor). Under driveway pavement
and sidewalks structural fill should be compacted to 90 percent, with the exception of the top 12 -
inches which should be compacted to 95 percent. Fill adjacent to foundations should be
compacted to 90 percent (95 percent if supporting slabs, patio's, porches, or structural elements).
Foundations
The new home may be supported on a conventional spread footing foundation provided the
footings extend down to dense site soil or are supported on structural fill as follows: Where
loose fill/topsoil is present, the loose fill/topsoil should be removed. Loose to medium dense
soils that underlies the fill/topsoil (such as encountered in the western portion of lot) should be
compacted and a 2 foot thick rock pad compacted into base soil. The crushed rock pad may
consist of 2 to 6 inch clean rock or recycled concrete (no minus). Spread footings may be
supported on the rock pad or on structural fill (meeting 95% compaction specifications) placed
above the rock pad in order to bring the subgrade back up to the desired footing elevation.
GF,o Group Northwest, Inc.
August 7, 2006
Geotechnical Study
8910 - 178` Place SW, Edmonds, WA
G-2310
Page 7
To properly transfer building Ioads to the bearing stratum, structural fill and rock below footings
should create a prism that extends out and below the footing at 1H:2V (minimum). Therefore, if
5 feet of over -excavation is required, the structural fill/rock pad should extend out and down
below both sides of the footing a minimum of 2.5 feet.
Near the existing embankment along 178t' Place SW, the bottom of the footings should be deep
enough to be below a 1H:IV line (or plane) that is projected up from base of the embankment.
The following foundation design criteria are applicable to spread footing foundations that are
supported as described above:
• Allowable bearing pressure, including all dead and live loads:
• Minimum depth to bottom of perimeter footing below
adjacent final exterior grade:
• Minimum depth to bottom of interior footings
below top of floor slab:
• Minimum width of strip wall footings:
• Minimum lateral dimension of column footings:
• Estimated Post -construction settlement:
— Across building width:
2,000 psf
24 inches
= 12 inches
= 16 inches
= 24 inches
112 inch
= 112 inch
A one-third increase in the above allowable bearing pressures can be used when considering
short-term transitory wind or seismic loads. Lateral loads can also be'resisted by friction
between the foundation and the supporting compacted fill subgrade or by passive earth pressure
acting on the buried portions of the foundations. For the latter, the foundations must be poured
"neat" against the existing undisturbed soil or backfilled with a compacted fill meeting the
requirements of structural fill. Our recommended parameters are as follows:
GEo Group Northwest, Inc.
August 7, 2006
Geotechnical Study
8910 - 178' Place SW, Edmonds, WA
- Passive Pressure (Lateral Resistance)
• 350 pcf equivalent fluid weight for dense site soils and structural fill
- Coefficient of Friction (Friction Factor)
• 0.35 for dense site soils and structural fill
Slab -on -Grade Floors
G-2310
Page 8
Slab -on -grade floors should be supported on dense site soils, on compacted engineered structural
fill that extends down to dense soil, or on a subgrade prepared as follows: Remove loose
fill/topsoil, compact the underlying soils if loose to medium dense. Place structural fill
consisting of a granular material, such as a sand/gravel pit run, to bring the subgrade back up to
the desired elevation. Compact the structural fill to 95% of the material's maximum dry
density, in accordance with structural fill specifications,
Slab -on -grade floors should be -placed on a capillary break to prevent wicking of moisture
through the slab. The capillary break should consist of a minimum of six (6) inch thick free -
draining layer of 1.5 inch minus gravel containing no more than five (5) percent fines passing the
No. 4 (114 -inch) sieve. To reduce water vapor transmission through the slab we recommend
installing a 10 -mil reinforced vapor barrier, such as Moistop' by Fortifiber Corporation, between
the capillary break and concrete floor slab, Two to four inches of sand may be placed over the
membrane for protection during construction (optional).
Drainage
If feasible, the finished ground of the site should be graded such that surface water is directed
away from the building structure. During construction, water should not be allowed to stand in
areas where footings, slabs, or pavements are to be constructed.
It is recommended that a subsurface footing drain be installed around the perimeter foundation
footing. The footing drain should consist of a four (4) inch minimum diameter, perforated, rigid
drain pipe laid at or near the bottom of the footing with a gradient sufficient to generate flow.
GEo Group Northwest, Inc.
August 7, 2006
G-2310
Geotechnical Study Page 9
8910 - IV' Place SW, Edmonds, WA
The drain line should be bedded on, surrounded by, and covered with a free -draining rock and
the drain rock should be protected with geotextile filter fabric, such as Miraf MON, or
equivalent; as shown on Plate 3, Typical Footing Drain.
Roof, yard, and other drain lines should not be connected to the footing drain system. The
footing drain should be separately tightlined to the storm drain. We recommend that sufficient
cleanouts be installed at strategic locations to allow for periodic maintenance of the footing
drains and roof down -spout tightline systems.
The lot is underlain by clay Transitional Beds that will act as a infiltration barrier. Infiltration of
surface water from roof, yard and other drains is not recommended. Infiltration of water into the
ground above the steep embankment along Puget Sound should be minimized. Storm water
should be discharged to the storm drain system.
Driveway Subgrade
The adequacy of driveway pavements is strictly related to the condition of the underlying
subgrade. If this is inadequate, no matter what pavement section is constructed, settlement or
movement of the subgrade will be reflected up through the paving. Where existing fill soils are
present, the driveway should be supported on a minimum of 3 feet of dense compacted material.
Prior to pouring the driveway, the subgrade should be proof -rolled with a loaded dump truck and
areas of soft, wet, or unstable subgrade should be removed and replaced with a granular
structural fill or crushed rock. Inclusion of reinforcement steel is recommended in a concrete
driveway with doweling across expansion joints.
GEo Group Northwest, Inc.
August 7, 2006 G-2310
Geotechnical Study Page 10
8910 - 178` Place SW, Edmonds, WA
LIMITATIONS
This report has been prepared for the specific application to the subject project. The findings
and recommendations stated herein are based on our field observations, the subsurface
conditions encountered in our site exploration, our experience, and judgement. The
recommendations are our professional opinion derived in a manner consistent with the level of
care and skill ordinarily exercised by other members of the profession currently practicing under
similar conditions in this area and within the budget constraint. No warranty is expressed or
implied. In the event that soil conditions vary during site work, GEo Group Northwest, Inc.
should be notified and the recommendations herein re-evaluated, and where necessary, be
revised. GEo Group Northwest, Inc. should be retained to review the final design plans to
confirm the validity of the recommendations contained in this report if there are significant
changes to the project as described herein.
PLAN REVIEW AND CONSTRUCTION MONITORING
It is recommended that we be retained to perform a general review of the final design and
specifications to verify that the earthwork, foundation, and other recommendations have been
properly interpreted and implemented in the design and engineering plan documents.
During construction, GEO Group Northwest should provide geotechnical monitoring/inspection
services. This will allow us to confirm that the subsurface conditions are consistent with those
described in this report and allow design changes in the event subsurface conditions differ from
those anticipated prior to the start of construction. It will allow us to evaluate whether the
geotechnical aspects of the construction activities conform to.the contract plans and
specifications.
GEo Group Northwest, Inc.
August 7, 2006 G-2310
Geotechnical Study Page I I
8910 - 178` Place SW, Edmonds, WA
Please contact us if you have any questions regarding this report or if additional information is
needed.
Sincerely,
GEo Group Northwest, Inc.
Wade J. Lassey
Engineering Geologist
William Chang, P.E.
Principal
Attachments:
Illustrations Plate I - Vicinity Map
Plate 2 - Site PIan
Plate 3 - Typical Footing Drain Detail
Appendix A Test Pit Logs
GEo Group Northwest, Inc.
�was6
� 4
'3 .�` .
Engineerk-1g
111E�`'
Wade J, L.assey
ILLUSTRATIONS
G-2310
Adapted from "The Thomas Guide," 2005.
0 1000, 2000'
Approximate Scale: 1 inch =1000 feet
VICINITY MAP
Group Northwest, Inc. 8910 -178th PLACE SW
Geotechnical Engineers, Geologists, &
Environmental Scientists EDMONDS, WASHINGTON
SCALE As Shown DATE 8/7/06 MADE WJL CHKD WC JOB NO. G72310 PLATE 1
LEGEND
Test Pit Number &
Approximate Location
TP -1
Adapted from Snohomish County Online Property Information http://gis.co.snohornish.wa.us/maps/propteryt/MapFrame.htm
SITE PLAN
Group Northwest, Inc. ALEKSEY ZORCHENKO LOT
Geotechnical Engineers, Geobgists, x 8910 - 178th PLACE SW
Environmental Scientists EDMONDS, WASHINGTON
SCALE As Shown DATE 8/7/06 MADE WJL CHKD WC JOS No. G-2310 PLATE 2
Basement Wall
Slope to drain VERTICAL DRAIN -
0 0 ° 0 MAT
o ° o ° p (Miradrain 6000
O
0 0 or equivalent)
COMPACTED
0 ONSITE MATERIAL o o WATERPROOFING
�/ c7 0 c
0
00 0 0 0
0
fl0
° ° VAPOR .BARRIER
0 0 ° O
GEOTEXTILE.. ;.. "' ...... &R AK
FILTER FABRIC FOOTING
(Mirafi 140 N, or _
equivalent)
'' `— FOOTING DRAIN
WASHED DRAINROCK Minimum 4 -inch diameter rigid PVC
perforated pipe with positive
gradient to discharge
NOT TO SCALE
NOTES:
1.) Do not replace rigid PVC pipe with flexiible corrugated plastic pipe.
2.) Perforated PVC pipe should be tight jointed and laid with perforations
down, with positive gradient to discharge.
3.) Do not connect roof downspout drains into the footing drain line system.
4.) Backfill on the exterior of the foundation basement wall should be compacted
to a minimum of 90% of the maximum dry density based on ASTM D 1557 - Modified
Proctor (95% if supporting structural elements, such as porches, patio's, or slabs).
- FOOTING DRAIN DETAIL
Group Northwest, Inc. ALEKSEY ZORCHENKO LOT
�.r Geotechnical Engineers, Geologists, & 8910 -178th PLACE SW
Environmental Scientists EDMONDS, WASHINGTON
SCALE NONE DATE 8/7/06 MADE WIL CHKD WC JOB NO. G-23 10 PLATE 3
APPENDIX A
G-2310
TEST PIT LOGS
LEGEND OF SOIL CLASSIFICATION AND PENETRATION TEST
UNIFIED SOIL CLASSIFICATION SYSTEM (USCS)
MAJOR 131VISION
GROUP
TYPICAL DESCRIPTION
LABORATORY CLASSIFICATION CRITERIA
SYMBOL
WELT. GRADED GRAVELS, GRAVEL -SAND
Ca = (D601 DID) gteator than 4
CLEAN
GW
MIXTURE, LITTLE OR NO FINES
Cc P30') 1 (1310 * OW) between 1 3
GRAVELS
DETERMINE
and
PERCENTAGES OF
GRAVELS
(Gt[te or no
POORLY GRADED GRAVELS, AND GRAVEL -SAND
GRAVEL AND SANp
re
(MaThan Haff
Dines)
GP
MIXTURES LITTLE OR NO FINES
FROM GRAIN SIZE
NOT MfOrfING ABOVE REQUIREMENTS
Coarse Grains
DISTRIBUTION
ATTERBERG LIMITS BELOW
GRAINED SOILS
LargarThan No. 4
CURVE
Si—)
DIRTY
GM
SILTY GRAVELS, GRAVELSAND-SILT MIXTURES
A" LINE
GRAVELS
NT
or P.L LESSTHAN 4
OF FIM
CLAYEY GRAVELS, GRAVEL -SAND -CLAY
A7TERBE G UMTI S ABOVE
(with some
EXCEEDS 12%
tines)
GC
MIXTURES
COARSEGRAFNED
"AA""UNE
SOILS ARE
at RL MORETHAN T
CLASSIFIED AS
SANDS
CLEAN
SW
WELL GRADED SANDS, GRAVELLY SANDS,
FOLLOWSS
Cu = (08011110) greater than 8
LITTLE OR NO FINES
Cox (D302)1 @10. D60) buNmen 1 and 3
SANDS
(More Than Hail
Mare Than Half by
Cwrse Grains
Qiltfe or no
SP
POORLY GRADED SANDS, GRAVELLY SANDS,
-4,9% Fine Grained
NOT MEETING ABOVE REQUIREMENTS.
Weight Larger
Smaller Than Na.
fines)
LITTLE OR NO FINES
GW, GP SW
Thep No. 2DO
4 Slave)
ATfERBt=RG BELOW
Siena
DIRTY
SM
SILTY SANDS, SANDSfLT MIXTURES
> 12% Fine Grained-
LINE
'A' LINE
SANDS
GM, GC, SM, SC
CONT84T OF
with P.L LESS THAN 4
FrNEs
ATTERBE-RG UMfI'S ABOVE
(with some5
to 12% Fina
ExcEEDs 12%
fines)
SC
CLAYEY SANDS; SAND-CL.AY MXWRES
Grained: use dual
"A" UNE
symbols
with P,L MORE THAN 7
SILTS
Liquid Umit
INORGANIC SILTS, ROCK FLOUR, SANDY SILTS
(Balow A-L.ine on
< 50%
ML
OF SLIGHT PLASTICITY
60
Plasticity Char;
CHART A -Una
Liquid Limit
INORGANIC SILTS, MICACEOUS OR
FINE-GRAINED
Negligible
so.ASSING
SOILS
Organic)
> 56%
MH
DIATOMACEOUS, FINE SANDY OR SILTY SOIL
_]EVE
rNO.CH or OH
CLAYS
CLAYS
Liquid Limit
INORGANIC CLAYS OF LOW PLASTICITY,
40
CL
GRAVELLY, SANDY, OR SILTY CLAYS, CLEAN
�
(Above A Une on
<30%
CLAYS
z
Plastic" Chart,
Uqutd LimitINORGANIC
CLAYS OF HIGH PLASTICITY, FAT
Negligible
30}}
F
Organic)
> 54%
-
CLAYS
C3
CL or OL
/1
1
More Than Half by
20--
0
Weight Larger
Liquid Limit
ORGANIC SILTS AND ORGANIC SILT! CLAYS OF
jorMH ar OH
Than No. 200
ORGANIC SILTS &
< 5096
OL
LOW PLASTICITY
C
Sieve
CLAYS
10
(Below A -Line on
7
Plasticity Chart)
Liquid Limft
1
OH
ORGANIC CLAYS OF HIGH PLASTICITY
4
AA
OL M
>'
0
0
10 20 30 40 50 60 70 80 W 100
110
HIGHLY
ORGANIC SOILS
Pt
PEAT AND OTHER HIGHLY ORGANIC SOILS
LIQUID LIMIT (%)
SOIL PARTICLE SIZE
GENERAL GIJiDANCE OF SOIL ENGINEERING
PROPERTIES FROM STANDARD PENETRATION TEST (SPT)
U.S. STANDARD SIEVE
FRACTION
Passing
Retained
SANDY SOILS
SILTY & CLAYEY SOILS
Size
Size
Sieve
(MM){m113(
Sieve
Blow
Counts
Relative
Density
Friction
Angle
Description
Blow
Counts
Unconfined
Sbength
Description
SILT 1 CLAY
#200
0.075
N
%
(D, degree
N
qu tit
SAND
0-4
0-15
VeryLOD"
42
-015
Vey soft
FINE
#40
0.425
#200
0.075
4-10
15-35
25-30
Loose
2-4
0-25-0.50
Soft
MEDIUM
#10
200
1140
0.425
10-30
35.65
28-35
MediumDonse,
4-8
D-50-1.00
Madium Skiff
COARSE
#4
4.75
#10
200
30 -SD
> 50
65-86
85-100
36-42
38-48
Dense
VeryDense
8-15
16-30
1.00 - 200
2.00-4,00
Stift
Very Stiff
GRAVEL
FINE
19
#4
4-75
1
1 1>
30
> 4.00
Hard
COARSE
76
19
—+
/ Group Northwest, Inc.
COBBLES
78 mm to 203 mm
BOULDERS
>203mm
,
Geatechniral Engineers, Geolo gists, &
EnVLrmmmentaiScientists
ROCK I
>78mm
FRAGMENTS IE
F
13240 NE 20th Street, Suite 12 Bellevue, WA 98005
5
Phone (425) 6498757 Fax (425) 649A758
PLATE Al
ROCK
>0.76 cubic meter in volume
TEST PIT NO. TP -1
LOGGED BY W3L TEST PIT DATE: 7/14/06 GROUND ELEV. feet lam)
DEPTH
ft.
USCS
SOIL DESCRIPTION
Sample
No.
Moisture
%
COMMENTS
ft.
SM
TOP SOIL, dark brown silty SAND, loose dry
No.
%
COMMENTS
— — --
Sl
7.3
SM
some roots and occasional wood debris (FILL)
S 1
8.8
- Probed 6" at
SSP -SAND
with gravel and some silt, tan, fine to medium
ft
--------------------------------
SM
grained, medium dense to dense, damp
S2
5.4
--
— — — — — — — — — — — — — — — — — — — — — — —
52
8.4
-Probed<l"
5
at4ft
5--
GP
Gravelly SAND, tan, very dense, damp
S3
6.1
S3
4.5
Total Depth = 7 feet
Gravelly SAND with some silt, red -brown, fine to medium
5 5 ft
SM
No Water Seepage Encountered
Location: East end of lot
I. S4
7.5
10
SM
Silty SAND with gravel, red brown, dense, some
I S5
3.2
TEST PIT NO. TP -2
LOGGED BY W1L TEST PIT DATE: 7114/06 GROUND ELEV. feet ( )
DEPTH
Sample
Moisture
ft.
USCS
SOIL DESCRIPTION
No.
%
COMMENTS
Silty SAND with gravel, brown, dense to medium dense,
SM
some roots and occasional wood debris (FILL)
S 1
8.8
-Probed 1" to
8"
--------------------------------
SP-
Gravelly SAND with some silt, mixed red -brown & dark
SM
brown, loose, damp, some charcoal & roots (FILL)
52
8.4
- Probed 1.5
f1a#oft
5--
SM
TOPSOIL layer, dark brown silty SAND, loose, dry
S3
6.1
- Probed 3" at
SP-
Gravelly SAND with some silt, red -brown, fine to medium
5 5 ft
SM
grained, dense, damp
I. S4
7.5
SM
Silty SAND with gravel, red brown, dense, some
I S5
3.2
cobbles/boulders to 12 inches, damp
10
Total Depth = 9 feet
No Water Seepage
Location: Middle of lot
Group Northwest, Inc.
Geolechnkal Engineers, Geologists, &
Environmental Scientists
TEST PIT LOGS
VACANT RESIDENTIAL LOT
8910 -178TH PLACE SW
EDMONDS, WASHINGTON
,JOB NO. G-2310 DATE 12/12/05 PLATE A2
TEST PIT - NO. TP -3
LOGGED BY WJL TEST PIT DATE: 7/14106 GROUND ELEV. feet it)
DEPTH
ft.
USCS
SOIL DESCRIPTION
Sample
NO.
Moisture
%
COMMENTS
5
Silty SAND with gravel, dark brown, dense, damp, some
wood and platic (FILL)
- Probed 1" at
S1
10.8
2 ft
SM--------,_�
_ �_-----
- Probed 17"„
Silty SAND with gravel and sandy SILT, dark brown and
at 3.5 ft
5
gray, mixed, loose, moist (FILL)
S2
13.1
i___----___
._.�
-Probed 19”
at5ft
SM
Silty SAND with gravel, brown, fine to medium grained,
loose to medium dense, very moist
S3
11.8
10
_
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
S4
40.1
CL
CLAY, tan, moderate plasticity, very stiff to hard, damp
Total Depth= 10.5 feet
No Water Seepage Encountered
Location West end of lot
I TEST PIT NO. I
LOGGED BY TEST PIT DATE: GROUND ELEV. feet (1)
DEPTH
ft.
USCS
SOIL_ DESCRIPTION
Sample
No.
Moisture
%
COMMENTS
5
Group Northwest, Inc.
Geotechnical Engineers, Geologists, &
Environmental scientists
TEST PIT LOGS
VACANT RESIDENTIAL LOT
8910 -178TH PLACE SW
EDMONDS, WASHINGTON
JOB NO. G-2310 DATE 12/12/05 PLATE A3