HomeMy WebLinkAboutRS_Geotech Report (TPN 3342103216 3108 Park Ave N Geo Report)_2023_11_27_v1.pdf15365 N.E. 90th Street, Suite 100 • Redmond, WA 98052 • (425) 449-4704 • FAX (425) 449-4711
Earth Solutions NW LLC
Geotechnical Engineering, Construction
Observation/Testing and Environmental Services
November 27, 2023
ES-9475
Park AVE 5, LLC
3412 – 210th Place Northeast
Sammamish, Washington 98074
Attention: Kevin Rech
Subject: Geotechnical Evaluation
Proposed Short Plat
3108 Park Avenue North
Renton, Washington
Dear Kevin:
As requested, Earth Solutions NW, LLC (ESNW) has prepared this geotechnical evaluation for
the subject site. We performed our work in general accordance with the scope of services
outlined in our proposal PES-9475, which was authorized by you on September 20, 2023. A
summary of the subsurface exploration and pertinent geotechnical recommendations for site
development are provided in this letter. Based on our evaluation, the proposed project is feasible
from a geotechnical standpoint.
Project Description
We understand the project will include construction of several new single-family residential
structures and related infrastructure improvements. We assume the proposed residential
structures will be two to three stories in height and constructed utilizing relatively lightly loaded
wood framing supported on conventional continuous and spread footing foundations. We
anticipate perimeter footing loads of about 1 to 2 kips per linear foot, column loads of up to 20
kips, and slab-on-grade loading of roughly 150 pounds per square foot (psf).
We understand infiltration is being evaluated as part of the overall storm design. Our evaluation
of site infiltration capacity was completed in general accordance with the requirements of the City
of Renton’s 2022 Stormwater Design Manual (2022 SWDM), which locally modifies the 2021 King
County Surface Water Design Manual (2021 KCSWDM). Discussion on infiltration feasibility can
be found in the Infiltration Feasibility section of this letter.
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Earth Solutions NW, LLC
Surface Conditions
The subject site is located at 3108 Park Avenue North in Renton, Washington. The approximate
location of the site is illustrated on the attached Vicinity Map (Plate 1). The property is comprised
of one tax parcel (King County Parcel No. 3342103216), totaling about 0.59 acres. The site is
currently developed with a single-family residence and associated improvements. Vegetation
surrounding the structures consists of grass landscaping areas and scattered trees. The site
topography gently descends from east to west, with about 15 feet of elevation change across the
property.
Subsurface Conditions
An ESNW representative observed, logged, and sampled four test pits, excavated at accessible
locations within the property boundaries, on October 11, 2023, using a mini-trackhoe and
operator retained by ESNW. The approximate locations of the test pits are depicted on Plate 2
(Test Pit Location Plan). Please refer to the attached test pit logs for a more detailed description
of subsurface conditions. Representative soil samples collected at the test pit locations were
evaluated in general accordance with Unified Soil Classification System (USCS) and United
States Department of Agriculture (USDA) methods and procedures.
Topsoil
Topsoil was observed extending to depths of approximately 12 to 18 inches below the existing
ground surface (bgs). The topsoil was characterized by dark brown color and fine organic
material.
Native Soil
Underlying topsoil, native soil was encountered as loose to dense poorly graded sand with silt,
silty sand, and sandy silt (USCS: SP-SM, SM, and ML, respectively). Native soil relative density
generally increased with depth. Native soil was generally encountered in a moist to wet condition.
Geologic Setting
The referenced geologic map identifies Vashon recessional outwash deposits (Qvr) across the
subject property and surrounding area. As described on the geologic map resource, recessional
outwash deposits consist primarily of moderately sorted to well-sorted, stratified gravel and sand.
Recessional outwash deposits were deposited by meltwater flowing from the receding Vashon
glacier.
The referenced Web Soil Survey (WSS) identifies Indianola loamy sand (Map Unit: InC) as the
primary soil unit underlying the subject site. The Indianola series was formed in terraces, kames,
and eskers and is derived from sandy glacial outwash.
Based on our field observations, native soil likely to be exposed during grading activities will be
generally consistent with recessional outwash deposits overlying glacial till deposits and Indianola
series soil.
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Groundwater
Groundwater seepage was not encountered during July 2023 subsurface exploration. However,
iron oxide staining was observed at depths of about two and one-half to five feet bgs which is
indicative of seasonal groundwater seepage. Glacial deposits commonly exhibit seasonal,
perched seepage zones. Groundwater seepage rates and elevations fluctuate depending on
many factors, including precipitation duration and intensity, the time of year, and soil conditions.
In general, groundwater flow rates are higher during the winter, spring, and early summer months.
Geologically Hazardous Areas
As part of this assessment, ESNW reviewed Chapter 4.3.050 of the Renton Municipal Code
(RMC) and County-maintained online mapping to evaluate the site for the presence of
geologically hazardous areas, as defined by the City. Based on review of the referenced RMC
and City maps, the subject site is not mapped within, or adjacent to, any geologic hazard areas.
Based on our fieldwork performed at the subject site, it is our opinion the site does not contain
geologically hazardous areas.
Structural Fill
Structural fill is defined as compacted soil placed in foundation, slab-on-grade, roadway,
permanent slope, retaining wall, and utility trench backfill areas. Structural fill placed and
compacted during site grading activities should meet the following specifications and guidelines:
Structural fill material Granular soils*
Moisture content At or slightly above optimum**
Relative compaction (minimum) 95 percent (Modified Proctor)
Loose lift thickness (maximum) 12 inches
* The existing soil may not be suitable for use as structural fill unless the soil is at (or slightly above) the optimum
moisture content at the time of placement and compaction.
** Soil shall not be placed dry of optimum and should be evaluated by ESNW during construction.
Temporary Excavations
Based on the soil conditions observed at the test pit locations, the following allowable temporary
slope inclinations, as a function of horizontal to vertical (H:V) inclination, may be used. The
applicable Federal Occupation Safety and Health Administration and Washington Industrial
Safety and Health Act soil classifications are also provided:
Areas exposing groundwater seepage 1.5H:1V (Type C)
Loose soil 1.5H:1V (Type C)
Medium dense soil 1H:1V (Type B)
Dense to very dense, cemented native soil 0.75H:1V (Type A)
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The presence of perched groundwater may cause localized sloughing of temporary slopes. An
ESNW representative should observe temporary and permanent slopes to confirm the slope
inclinations are suitable for the exposed soil conditions and to provide additional excavation and
slope recommendations, as necessary. If the recommended temporary slope inclinations cannot
be achieved, temporary shoring may be necessary to support excavations. Permanent slopes
should be planted with vegetation to enhance stability and to minimize erosion and should
maintain a gradient of 2H:1V or flatter.
Foundations
The proposed residential structures can be constructed upon a conventional continuous and
spread footing foundation system bearing on competent native soil or new structural fill placed
directly on competent native soil. Competent native soil suitable for support of foundations will
likely be encountered beginning at depths of about two to three feet bgs. We recommend
compacting the recessional outwash sand soil in-place where it is encountered in foundation
subgrade areas. ESNW should be retained during construction to perform a foundation subgrade
evaluation prior to formwork. Where loose or unsuitable conditions are encountered at foundation
subgrade elevations, compaction of the soils to the specifications of structural fill or
overexcavation and replacement with structural fill will be necessary.
Provided the structures are supported as recommended, the following parameters may be used
for foundation design:
Allowable soil bearing capacity 2,500 psf
Passive earth pressure 300 pcf
Coefficient of friction 0.40
The passive earth pressure value provided above assumes the foundation will be backfilled with
structural fill. A factor-of-safety of 1.5 has been applied to the passive earth pressure and
coefficient of friction values provided in this section. For short-term wind and seismic loading, a
one-third increase in the allowable soil bearing capacity may be assumed.
With structural loading as expected, total settlement in the range of one inch is anticipated, with
differential settlement of about one-half inch. Most of the anticipated settlement should occur
during construction as dead loads are applied.
Slab-on-Grade Floors
Slab-on-grade floors for the proposed structures should be supported on a well-compacted, firm,
and unyielding subgrade. Where feasible, native soils exposed at the slab-on-grade subgrade
level can likely be compacted in situ to the specifications described in this section. Unstable or
yielding areas of subgrade should be recompacted, or overexcavated and replaced with suitable
structural fill, prior to slab construction.
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A capillary break consisting of a minimum of four inches of free-draining crushed rock or gravel
should be placed below the slab. The free-draining material should have a fines content of 5
percent or less (where the fines content is defined as the percent passing the Number 200 sieve,
based on the minus three-quarter-inch fraction). In areas where slab moisture is undesirable,
installation of a vapor barrier below the slab should be considered. If a vapor barrier is utilized,
it should be a material specifically designed for use as a vapor barrier and should be installed in
accordance with manufacturer specifications.
Retaining Walls
Retaining walls must be designed to resist earth pressures and applicable surcharge loads. The
following parameters may be used for design:
Active earth pressure (unrestrained condition) 35 pcf (equivalent fluid)
At-rest earth pressure (restrained condition) 55 pcf
Traffic surcharge* (passenger vehicles) 70 psf (rectangular distribution)
Passive earth pressure 300 pcf (equivalent fluid)
Coefficient of friction 0.40
Seismic surcharge 8H psf**
* Where applicable.
** Where H equals the retained height (in feet).
The passive earth pressure and coefficient of friction values include a safety factor of 1.5. The
above design parameters are based on a level backfill condition and level grade at the wall toe.
Revised design values will be necessary if sloping grades are to be used above or below retaining
walls. Additional surcharge loading from adjacent foundations, sloped backfill, or other relevant
loads should be included in the retaining wall design.
Retaining walls should be backfilled with free-draining material that extends along the height of
the wall and a distance of at least 18 inches behind the wall. In lieu of 18 inches of a free-draining
material, a drainage mat can be considered. ESNW should evaluate the suitability of drainage
mat application during construction. The upper 12 inches of the wall backfill may consist of a less
permeable soil, if desired. A perforated drainpipe should be placed along the base of the wall
and connected to an approved discharge location. A typical retaining wall drainage detail is
provided on Plate 3. If drainage is not provided, hydrostatic pressures should be included in the
wall design.
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Seismic Design
The 2018 International Building Code (2018 IBC) recognizes the most recent edition of the
Minimum Design Loads for Buildings and Other Structures manual (ASCE 7-16) for seismic
design, specifically with respect to earthquake loads. Based on the soil conditions encountered
at the test locations, the parameters and values provided below are recommended for seismic
design per the 2018 IBC.
Parameter Value
Site Class D*
Mapped short period spectral response acceleration, SS (g) 1.445
Mapped 1-second period spectral response acceleration, S1 (g) 0.497
Short period site coefficient, Fa 1.0
Long period site coefficient, Fv 1.803**
Adjusted short period spectral response acceleration, SMS (g) 1.445
Adjusted 1-second period spectral response acceleration, SM1 (g) 0.896**
Design short period spectral response acceleration, SDS (g) 0.963
Design 1-second period spectral response acceleration, SD1 (g) 0.597**
* Assumes medium dense to dense soil conditions (at depth), encountered to a maximum depth of 10 feet bgs
during the October 2023 field exploration, remain medium dense to dense to at least 100 feet bgs.
** Values assume Fv may be determined using linear interpolation per Table 11.4-2 in ASCE 7-16.
Liquefaction
Liquefaction is a phenomenon that can occur within a soil profile as a result of an intense ground
shaking or loading condition. Most commonly, liquefaction is caused by ground shaking during
an earthquake. Sand or silt soil that is loose, cohesionless, and below the groundwater table are
most susceptible to liquefaction. During the ground shaking, the soil contracts, and porewater
pressure increases. The increased porewater pressure occurs quickly and without sufficient time
to dissipate, resulting in water flowing upward to the ground surface and a liquefied soil
condition. Soil in a liquefied condition possesses very little shear strength in comparison to the
drained condition, which can result in a loss of foundation support for structures.
The referenced liquefaction susceptibility map indicates the subject site maintains low to
moderate liquefaction susceptibility. In our opinion, site susceptibility to liquefaction may be
considered low. The relative density of the native soil and absence of an established shallow
groundwater table are the primary bases for this opinion.
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Earth Solutions NW, LLC
Drainage
Zones of perched groundwater seepage should be anticipated in site excavations depending on
the time of year grading operations take place. Temporary measures to control surface water
runoff and groundwater during construction would likely involve passive elements such as
interceptor trenches and sumps. ESNW should be consulted during preliminary grading to
identify areas of seepage and to provide recommendations to reduce the potential for instability
related to seepage effects.
Finish grades must be designed to direct surface drain water away from the structures. Water
must not be allowed to pond adjacent to the structure. Grades adjacent to the building should be
sloped away from the building at a gradient of either at least 2 percent for a horizontal distance
of 10 feet or the maximum allowed by adjacent structures. In our opinion, footing drains should
be installed along building perimeter footings. A typical footing drain detail is provided on Plate
4.
Infiltration Feasibility
As indicated in the Subsurface Conditions section of this letter, native soils encountered during
the fieldwork were characterized primarily as recessional outwash sand deposits underlain by
glacial till deposits. In our opinion, infiltration is feasible in areas where adequate separation from
impermeable layers can be established or in areas where cleaner sand deposits are exposed
underlying impermeable layers.
For preliminary design purposes, we recommend a preliminary long-term design rate of one inch
per hour. Use of this rate requires the infiltration facilities to be sited within relatively clean sand
deposits. Adequate separation between the infiltration facility bottom and seasonal high
groundwater levels or impermeable layers must be established. In-situ infiltration testing will be
required by the City to confirm infiltration rates.
ESNW can provide further evaluation and recommendations for site BMPs as plans develop.
ESNW should review final stormwater management plans to provide supplementary
recommendations, as needed. Additionally, ESNW should observe infiltration system
excavations and construction to confirm suitable soil conditions if infiltration is pursued.
Limitations & Additional Services
This geotechnical evaluation report has been prepared for the exclusive use of Park AVE 5, LLC
and its representatives. The recommendations and conclusions provided in this letter are
professional opinions consistent with the level of care and skill that is typical of other members in
the profession currently practicing under similar conditions in this area. A warranty is not
expressed or implied. Variations in the soil and groundwater conditions observed at the test sites
may exist and may not become evident until construction. ESNW should reevaluate the
conclusions in this letter if variations are encountered.
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Earth Solutions NW, LLC
ESNW should have an opportunity to review the final design with respect to the geotechnical
recommendations provided in this letter. ESNW should also be retained to provide testing and
consultation services during the earthwork phase of construction.
We trust this letter meets your current needs. Should you have any questions regarding the
content herein, or require additional information, please call.
Sincerely,
EARTH SOLUTIONS NW, LLC
Kyler T. Kelly, L.G. Henry T. Wright, P.E.
Project Geologist Associate Principal Engineer
Attachments: Plate 1 – Vicinity Map
Plate 2 – Test Pit Location Plan
Plate 3 – Retaining Wall Drainage Detail
Plate 4 – Footing Drain Detail
Test Pit Logs
Grain Size Distribution
References:
RMC
2022 SWDM
2021 KCSWDM
Liquefaction Susceptibility for King County (Map 11-5), incorporating data from the
Washington State Department of Natural Resources, dated May 2010
Geologic Map of King County, Washington, compiled by D.B. Booth et al., dated March
2007
WSS, maintained by the Natural Resources Conservation Service under the USDA
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Drawn CAM
Checked KTK Date Nov. 2023
Date 11/03/2023 Proj. No. 9475
Plate 1
Geotechnical Engineering,Construction
Observation/Testing and Environmental Services
Earth Solutions NWLLCEarthSolutionsNWLLC
EarthSolutions
NW LLC
Vicinity Map
3108 Park Avenue N.
Renton, Washington
Reference:
King County, Washington
OpenStreetMap.org
NORTH
NOTE: This plate may contain areas of color. ESNW cannot be
responsible for any subsequent misinterpretation of the information
resulting from black & white reproductions of this plate.
Renton
SITE
Newcastle
Lake Washington
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Checked KTK Date Nov. 2023
Date 11/03/2023 Proj. No. 9475
Plate 2
Geotechnical Engineering,Construction
Observation/Testing and Environmental Services
Earth Solutions NWLLCEarthSolutionsNWLLC
EarthSolutions
NW LLC
TP-1
TP-2
TP-3
TP-4
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Test Pit Location Plan
3108 Park Avenue N.
Renton, Washington
NOTE: This plate may contain areas of color. ESNW cannot be
responsible for any subsequent misinterpretation of the information
resulting from black & white reproductions of this plate.
NOTE: The graphics shown on this plate are not intended for design
purposes or precise scale measurements, but only to illustrate the
approximate test locations relative to the approximate locations of
existing and / or proposed site features. The information illustrated
is largely based on data provided by the client at the time of our
study. ESNW cannot be responsible for subsequent design changes
or interpretation of the data by others.
LEGEND
Approximate Location of
ESNW Test Pit, Proj. No.
ES-9475, Oct. 2023
Subject Site
Existing Building
TP-1
NOT - TO - SCALE
NORTH
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Geotechnical Engineering,Construction
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Drawn CAM
Checked KTK Date Nov. 2023
Date 11/03/2023 Proj. No. 9475
Plate 3
Earth Solutions NWLLCEarthSolutionsNWLLC
EarthSolutions
NW LLC
NOTES:
Free-draining Backfill should consist
of soil having less than 5 percent fines.
Percent passing No. 4 sieve should be
25 to 75 percent.
Sheet Drain may be feasible in lieu
of Free-draining Backfill, per ESNW
recommendations.
Drain Pipe should consist of perforated,
rigid PVC Pipe surrounded with 1-inch
Drain Rock.
LEGEND:
Free-draining Structural Backfill
1-inch Drain Rock
18" Min.
Structural
Fill
Perforated Rigid Drain Pipe
(Surround in Drain Rock)
SCHEMATIC ONLY - NOT TO SCALE
NOT A CONSTRUCTION DRAWING
Retaining Wall Drainage Detail
3108 Park Avenue N.
Renton, Washington
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Drawn CAM
Checked KTK Date Nov. 2023
Date 11/03/2023 Proj. No. 9475
Plate 4
Earth Solutions NWLLCEarthSolutionsNWLLC
EarthSolutions
NW LLC
Slope
Perforated Rigid Drain Pipe
(Surround in Drain Rock)
18" Min.
NOTES:
Do NOT tie roof downspouts
to Footing Drain.
Surface Seal to consist of
12" of less permeable, suitable
soil. Slope away from building.
LEGEND:
Surface Seal: native soil or
other low-permeability material.
1-inch Drain Rock
SCHEMATIC ONLY - NOT TO SCALE
NOT A CONSTRUCTION DRAWING
Footing Drain Detail
3108 Park Avenue N.
Renton, Washington
DR
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GW
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SP
SM
SC
ML
CL
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MH
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Well-graded gravel with
or without sand, little to
no fines
Poorly graded gravel with
or without sand, little to
no fines
Silty gravel with or without
sand
Clayey gravel with or
without sand
Well-graded sand with
or without gravel, little to
no fines
Poorly graded sand with
or without gravel, little to
no fines
Silty sand with or without
gravel
Clayey sand with or
without gravel
Silt with or without sand
or gravel; sandy or
gravelly silt
Clay of low to medium
plasticity; lean clay with
or without sand or gravel;
sandy or gravelly lean clay
Organic clay or silt of
low plasticity
Elastic silt with or without
sand or gravel; sandy or
gravelly elastic silt
Clay of high plasticity;
fat clay with or without
sand or gravel; sandy or
gravelly fat clay
Organic clay or silt of
medium to high plasticity
Peat, muck, and other
highly organic soils
EEaarrtthh SSoolluuttiioonnss NNWW LLC
Geotechnical Engineering,Construction
Observation/Testing and Environmental Services
EXPLORATION LOG KEY
Fi
l
l FILL Made Ground
Classifications of soils in this geotechnical report and as shown on the exploration logs are based on visual
field and/or laboratory observations, which include density/consistency, moisture condition, grain size, and
plasticity estimates, and should not be construed to imply field or laboratory testing unless presented herein.
Visual-manual and/or laboratory classification methods of ASTM D2487 and D2488 were used as an
identification guide for the Unified Soil Classification System.
Terms Describing Relative Density and Consistency
Coarse-Grained Soils:
Fine-Grained Soils:
SPT blows/foot
SPT blows/foot
Test Symbols & Units
Fines = Fines Content (%)
MC = Moisture Content (%)
DD = Dry Density (pcf)
Str = Shear Strength (tsf)
PID = Photoionization Detector (ppm)
OC = Organic Content (%)
CEC = Cation Exchange Capacity (meq/100 g)
LL = Liquid Limit (%)
PL = Plastic Limit (%)
PI = Plasticity Index (%)
Component Definitions
Descriptive Term Size Range and Sieve Number
Smaller than No. 200 (0.075 mm)
Boulders
Modifier Definitions
Percentage by
Weight (Approx.)
< 5
5 to 14
15 to 29
> 30
_
Modifier
Trace (sand, silt, clay, gravel)
Slightly (sandy, silty, clayey, gravelly)
Sandy, silty, clayey, gravelly
Very (sandy, silty, clayey, gravelly)
Moisture Content
Dry - Absence of moisture, dusty, dry to
the touch
Damp - Perceptible moisture, likely below
optimum MC
Moist - Damp but no visible water, likely
at/near optimum MC
Wet - Water visible but not free draining,
likely above optimum MC
Saturated/Water Bearing - Visible free
water, typically below groundwater table
Symbols
Cement grout
surface seal
Bentonite
chips
Grout
seal
Filter pack with
blank casing
section
Screened casing
or Hydrotip with
filter pack
End cap
ATD = At time
of drilling
Static water
level (date)
_> 50
Density
Very Loose
Loose
Medium Dense
Dense
Very Dense
Consistency
Very Soft
Soft
Medium Stiff
Stiff
Very Stiff
Hard
< 4
4 to 9
10 to 29
30 to 49
< 2
2 to 3
4 to 7
8 to 14
15 to 29
_> 30
LLC
EarthSolutions
NW LLC
Cobbles
Gravel
Coarse Gravel
Fine Gravel
Sand
Coarse Sand
Medium Sand
Fine Sand
Silt and Clay
Larger than 12"
3" to 12"
3" to No. 4 (4.75 mm)
3" to 3/4"
3/4" to No. 4 (4.75 mm)
No. 4 (4.75 mm) to No. 200 (0.075 mm)
No. 4 (4.75 mm) to No. 10 (2.00 mm)
No. 10 (2.00 mm) to No. 40 (0.425 mm)
No. 40 (0.425 mm) to No. 200 (0.075 mm)DR
A
F
T
GB
GB
GB
MC = 13.6
Fines = 29.5
MC = 9.9
MC = 20.7
TPSL
SM
SM
Dark brown TOPSOIL
Dark brown silty SAND, loose, moist
Brown silty SAND, medium dense, moist
[USDA Classification: slightly gravelly fine sandy LOAM]
-probed 8"
-light iron oxide staining to 5', roots
-becomes gray, dense, weakly cemented
-probed 2"
-boulder
-becomes wet
Test pit terminated at 9.0 feet below existing grade. No groundwater encountered during
excavation. No caving observed.
LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed.
Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a
standalone document. Refer to the text of the geotechnical report for a complete understanding
of subsurface conditions.
1.5
2.0
9.0
SA
M
P
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E
T
Y
P
E
NU
M
B
E
R
DE
P
T
H
(f
t
)
0.0
2.5
5.0
7.5
PAGE 1 OF 1
TEST PIT NUMBER TP-1
CHECKED BY HTW
NOTES
SURFACE CONDITIONS Grass
AT TIME OF EXCAVATIONAT TIME OF EXCAVATION
AFTER EXCAVATION
EXCAVATION CONTRACTOR NW Excavating
DATE STARTED 10/11/23 COMPLETED 10/11/23
GROUND WATER LEVEL:
GROUND ELEVATION
LOGGED BY KTK
LATITUDE 47.51985 LONGITUDE -122.20084
PROJECT NUMBER ES-9475 PROJECT NAME 3108 Park Avenue N.
GE
N
E
R
A
L
B
H
/
T
P
/
W
E
L
L
-
9
4
7
5
.
G
P
J
-
G
I
N
T
U
S
.
G
D
T
-
1
1
/
2
7
/
2
3
Earth Solutions NW, LLC
15365 N.E. 90th Street, Suite 100
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
TESTS
U.
S
.
C
.
S
.
MATERIAL DESCRIPTION
GR
A
P
H
I
C
LO
G
DR
A
F
T
GB
GB
GB
GB
MC = 7.3
MC = 7.4
Fines = 9.3
MC = 20.6
MC = 26.2
TPSL
SP-
SM
ML
Dark brown TOPSOIL
Brown poorly graded SAND with silt, medium dense, moist
-probed 8"
-light iron oxide staining to 5'
[USDA Classification: slightly gravelly SAND]
Gray sandy SILT, dense, moist to wet
-weakly cemented
Test pit terminated at 10.0 feet below existing grade. No groundwater encountered during
excavation. No caving observed.
LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed.
Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a
standalone document. Refer to the text of the geotechnical report for a complete understanding
of subsurface conditions.
1.5
5.0
10.0
SA
M
P
L
E
T
Y
P
E
NU
M
B
E
R
DE
P
T
H
(f
t
)
0.0
2.5
5.0
7.5
10.0
PAGE 1 OF 1
TEST PIT NUMBER TP-2
CHECKED BY HTW
NOTES
SURFACE CONDITIONS Grass
AT TIME OF EXCAVATIONAT TIME OF EXCAVATION
AFTER EXCAVATION
EXCAVATION CONTRACTOR NW Excavating
DATE STARTED 10/11/23 COMPLETED 10/11/23
GROUND WATER LEVEL:
GROUND ELEVATION
LOGGED BY KTK
LATITUDE 47.51969 LONGITUDE -122.20074
PROJECT NUMBER ES-9475 PROJECT NAME 3108 Park Avenue N.
GE
N
E
R
A
L
B
H
/
T
P
/
W
E
L
L
-
9
4
7
5
.
G
P
J
-
G
I
N
T
U
S
.
G
D
T
-
1
1
/
2
7
/
2
3
Earth Solutions NW, LLC
15365 N.E. 90th Street, Suite 100
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
TESTS
U.
S
.
C
.
S
.
MATERIAL DESCRIPTION
GR
A
P
H
I
C
LO
G
DR
A
F
T
GB
GB
GB
GB
MC = 12.9
MC = 14.5
Fines = 52.9
MC = 10.2
MC = 8.4
Fines = 13.2
TPSL
SM
ML
SM
Dark brown TOPSOIL
Brown silty SAND, loose, moist
-light iron oxide staining to 4.5', probed 8"
Gray sandy SILT, medium dense, moist
-becomes dense, weakly cemented
[USDA Classification: slightly gravelly LOAM]
-probed 3"
-boulder
Gray silty SAND, medium dense to dense, moist
[USDA Classification: slightly gravelly SAND]
Test pit terminated at 10.0 feet below existing grade. No groundwater encountered during
excavation. No caving observed.
LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed.
Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a
standalone document. Refer to the text of the geotechnical report for a complete understanding
of subsurface conditions.
1.5
3.0
7.5
10.0
SA
M
P
L
E
T
Y
P
E
NU
M
B
E
R
DE
P
T
H
(f
t
)
0.0
2.5
5.0
7.5
10.0
PAGE 1 OF 1
TEST PIT NUMBER TP-3
CHECKED BY HTW
NOTES
SURFACE CONDITIONS Grass
AT TIME OF EXCAVATIONAT TIME OF EXCAVATION
AFTER EXCAVATION
EXCAVATION CONTRACTOR NW Excavating
DATE STARTED 10/11/23 COMPLETED 10/11/23
GROUND WATER LEVEL:
GROUND ELEVATION
LOGGED BY KTK
LATITUDE 47.51972 LONGITUDE -122.20138
PROJECT NUMBER ES-9475 PROJECT NAME 3108 Park Avenue N.
GE
N
E
R
A
L
B
H
/
T
P
/
W
E
L
L
-
9
4
7
5
.
G
P
J
-
G
I
N
T
U
S
.
G
D
T
-
1
1
/
2
7
/
2
3
Earth Solutions NW, LLC
15365 N.E. 90th Street, Suite 100
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
TESTS
U.
S
.
C
.
S
.
MATERIAL DESCRIPTION
GR
A
P
H
I
C
LO
G
DR
A
F
T
GB
GB
GB
MC = 9.4
MC = 17.3
MC = 13.4
Fines = 32.9
TPSL
SP-
SM
SM
Dark brown TOPSOIL
Brown poorly graded SAND with silt, medium dense, moist
-probed 6"
-becomes dense, weakly cemented, light iron oxide staining to 5'
Gray silty SAND, dense, moist to wet
-weakly cemented
-reduced fines content to BOH
[USDA Classification: slightly gravelly sandy LOAM]
Test pit terminated at 10.0 feet below existing grade. No groundwater encountered during
excavation. No caving observed.
LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed.
Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a
standalone document. Refer to the text of the geotechnical report for a complete understanding
of subsurface conditions.
1.0
5.0
10.0
SA
M
P
L
E
T
Y
P
E
NU
M
B
E
R
DE
P
T
H
(f
t
)
0.0
2.5
5.0
7.5
10.0
PAGE 1 OF 1
TEST PIT NUMBER TP-4
CHECKED BY HTW
NOTES
SURFACE CONDITIONS Grass
AT TIME OF EXCAVATIONAT TIME OF EXCAVATION
AFTER EXCAVATION
EXCAVATION CONTRACTOR NW Excavating
DATE STARTED 10/11/23 COMPLETED 10/11/23
GROUND WATER LEVEL:
GROUND ELEVATION
LOGGED BY KTK
LATITUDE 47.51985 LONGITUDE -122.20162
PROJECT NUMBER ES-9475 PROJECT NAME 3108 Park Avenue N.
GE
N
E
R
A
L
B
H
/
T
P
/
W
E
L
L
-
9
4
7
5
.
G
P
J
-
G
I
N
T
U
S
.
G
D
T
-
1
1
/
2
7
/
2
3
Earth Solutions NW, LLC
15365 N.E. 90th Street, Suite 100
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
TESTS
U.
S
.
C
.
S
.
MATERIAL DESCRIPTION
GR
A
P
H
I
C
LO
G
DR
A
F
T
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
0.0010.010.1110100
2.74
LL
TP-01
TP-02
TP-03
TP-03
TP-04
0.077
3/4
U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS
GRAVEL SAND
9.5
4.75
37.5
4.75
4.75
%Silt
1.46
TP-01
TP-02
TP-03
TP-03
TP-04
2 2003
Cc CuClassification
%Clay
16
PID60 D30
coarse SILT OR CLAYfinemedium
GRAIN SIZE IN MILLIMETERS
3/8 50
2.0ft.
3.0ft.
4.0ft.
10.0ft.
10.0ft.
2.00ft.
3.00ft.
4.00ft.
10.00ft.
10.00ft.
PL
3
D100
140
Specimen Identification
1
fine
6
HYDROMETER
304
29.5
9.3
52.9
13.2
32.9
101/2
COBBLES
Specimen Identification
4
coarse
20 401.5 8 14
USDA: Brown Slightly Gravelly Fine Sandy Loam. USCS: SM.
USDA: Brown Slightly Gravelly Sand. USCS: SP-SM.
USDA: Gray Slightly Gravelly Loam. USCS: Sandy ML.
USDA: Gray Slightly Gravelly Sand. USCS: SM.
USDA: Gray Slightly Gravelly Sandy Loam.USCS: SM.
6 60
PE
R
C
E
N
T
F
I
N
E
R
B
Y
W
E
I
G
H
T
D10
0.077
0.155
0.167
0.2
0.212
0.105
0.313
0.25
GRAIN SIZE DISTRIBUTION
100
PROJECT NUMBER ES-9475 PROJECT NAME 3108 Park Avenue N
GR
A
I
N
S
I
Z
E
U
S
D
A
E
S
-
9
4
7
5
3
1
0
8
P
A
R
K
A
V
E
N
U
E
N
.
G
P
J
G
I
N
T
U
S
L
A
B
.
G
D
T
1
0
/
2
7
/
2
3
Earth Solutions NW, LLC
15365 N.E. 90th Street, Suite 100
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
DR
A
F
T