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DRAFT GEOTECHNICAL ENGINEERING DESIGN REPORT
SOOS CREEK TRAIL AND SIGNAL POLE
RENTON, WASHINGTON
by
Haley & Aldrich, Inc.
Seattle, Washington
for
Huitt-Zollars, Inc.
Seattle, Washington
File No. 0207911-000
April 2025
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HALEY & ALDRICH, INC. 3131 ELLIOTT AVENUE SUITE 600 SEATTLE, WA 98121 206.324.9530
www.haleyaldrich.com
SIGNATURE PAGE FOR
REPORT ON
SOOS CREEK TRAIL AND SIGNAL POLE
RENTON, WASHINGTON
PREPARED FOR
HUITT-ZOLLARS, INC.
SEATTLE, WASHINGTON
PREPARED BY:
Michael Liu, P.E.
Project Geotechnical Engineer
Haley & Aldrich, Inc.
REVIEWED AND APPROVED BY:
Jeff Bruce, P.E.
Senior Project Manager, Geotechnical Engineer
Haley & Aldrich, Inc.
Mike Schmitz, P.E.
Principal, Geotechnical Engineer
Haley & Aldrich, Inc.
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Table of Contents
Page
iii
List of Tables v
List of Figures v
List of Appendices v
1. Introduction 1
2. Purpose, Scope, and Use of This Report 2
3. Site and Project Description 3
4. Subsurface Conditions 4
4.1 LOCAL GEOLOGY 4
4.2 SOIL CONDITIONS 4
4.3 GROUNDWATER CONDITIONS 5
4.4 CORROSION TEST RESULTS 6
5. Seismic Considerations and Recommendations 7
5.1 SITE SOIL CLASS FOR SEISMIC DESIGN 7
5.2 DESIGN SEISMIC PARAMETERS 7
5.3 SEISMICALLY INDUCED GEOTECHNICAL HAZARDS 8
5.3.1 Surface Rupture 8
5.3.2 Liquefaction and Subsidence 8
5.3.3 Lateral Spreading 9
6. Geotechnical Analysis and Recommendations 9
6.1 DEEP FOUNDATION DESIGN 9
6.1.1 Deep Foundation Subsurface Design Profile 9
6.1.2 Deep Foundation Axial Resistance 11
6.1.3 Deep Foundation Seismic Displacement and Downdrag 11
6.1.4 Deep Foundation Lateral Resistance 12
6.1.5 Considerations for Pile Length 12
6.2 MODULAR BLOCK WALL 12
6.2.1 Global Stability Methods 12
6.2.2 Soil Properties 13
6.2.3 Groundwater 13
6.2.4 Global Stability Results 13
6.2.5 Wall Design Recommendations 14
6.3 TEMPORARY AND PERMANENT WALL DRAINAGE 14
6.4 ON-GRADE TRAIL PAVEMENT 14
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Table of Contents
Page
iv
7. Construction Recommendations 16
7.1 SITE PREPARATION AND GRADING 16
7.2 STRUCTURAL AND COMPACTED FILL 16
7.2.1 Imported Structural Fill 18
7.2.2 Use of Site Soil as Structural Fill 18
7.3 PERMANENT SLOPES 18
7.4 TEMPORARY OPEN CUTS 18
8. Recommended Additional Geotechnical Services 20
8.1 GEOTECHNICAL CONSTRUCTION SERVICES 20
References 21
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v
List of Tables
Table No. Title Page # (if embedded)
1 Groundwater Depths and Elevations during our Explorations 5
and Groundwater Monitoring
2 Corrosion Test Results 6
3 AASHTO Seismic Design Parameters 8
4 Design Soil Profiles at the Boardwalk and Signal Pole 10
5 Design Soil Profiles at the Signal Pole 10
6 Resistance Factors for Single-Driven Pipe Pile 11
7 Pile P-Multipliers, Pm, for Multiple Row Shading 12
(averaged from Hannigan et al., 2006)
8 Slope Stability Model Soil Parameters 13
List of Figures
Figure No. Title
1 Vicinity Map
2 Site and Exploration Plan STA 11+00 – STA 22+50
3 Site and Exploration Plan STA 22+50 – STA 33+00
4 Cross Section A-A’
5 Cross Section B-B’
List of Appendices
Appendix Title
A Field Exploration Logs
B Laboratory Testing Program
C Pile Capacities Figures
D Slope Stability Results
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1. Introduction
This geotechnical engineering design report presents Haley & Aldrich, Inc.’s (Haley & Aldrich’s)
recommendations for design and construction of the proposed Soos Creek Trail extension and signal
pole in Renton, Washington. We have organized this report into the following sections:
1. Introduction;
2. Purpose, Scope, and Use of This Report;
3. Site and Project Description;
4. Subsurface Conditions;
5. Seismic Considerations and Recommendations;
6. Geotechnical Analysis and Recommendations;
7. Construction Recommendations;
8. Recommended Additional Geotechnical Services; and
9. References.
Figures follow the text to illustrate the project area, exploration locations, and geotechnical design
recommendations. Appendices A and B present results of our field explorations and laboratory testing
program, respectively. Appendices C and D present results of our pile capacities and slope stability
analysis, respectively.
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2. Purpose, Scope, and Use of This Report
The purpose of our services is to provide Huitt-Zollars, Inc. (Huitt-Zollars), King County Parks and
Recreation Division, and their design consultants with geotechnical engineering recommendations for
design and construction of the proposed Soos Creek Trail and nearby signal pole structure. Our scope of
services includes:
Reviewing existing geotechnical information for relevance to the proposed work areas.
Drilling and conducting five exploratory soil borings and five test pits, collecting soil samples,
and completing laboratory analyses.
Installing a groundwater monitoring well in one of the five borings with vibrating wire
piezometer (VWP) and data logger for long-term groundwater monitoring.
Completing geotechnical engineering analyses, evaluations, and/or recommendations for:
– Subsurface and groundwater conditions;
– Seismic design parameters;
– Deep foundation design (for boardwalk and signal pole);
– Retaining wall global stability and design;
– Construction Recommendations, and
– Producing this geotechnical engineering design report.
Haley & Aldrich completed this work in general accordance with our contract with Huitt-Zollars, Inc.,
dated 25 November 2024. This report is for the exclusive use of Huitt-Zollars, King County Parks and
Recreation Division, and their design consultants. We developed our conclusions and recommendations
based on our current understanding of the project. If the nature or location of the project is different
than we have considered herein, Haley & Aldrich should be notified so we can confirm or modify our
recommendations. We completed our services in accordance with generally accepted geotechnical
engineering practices for similar types of projects and localities, related to the nature of the work
accomplished at the time the services were performed. No other warranty, expressed or implied, is
made.
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3. Site and Project Description
This project is an approximately 2,400 linear foot extension of the Soos Creek Trail north from its
existing terminus at SE 192nd Street to SE 186th Street and adding a new light pole feature on the north
side of SE 192nd Street in Renton, Washington. The project location is illustrated on Figure 1.
Haley & Aldrich understands that there is an existing wetland area on the northeast side of the
intersection of SE 192nd Street and 124th Avenue SE. The proposed trail section along SE 192nd Street
would be inside the wetland area. The wetland boundary is shown on Figure 2. The extension will
consist of the following:
Pile-supported boardwalk along north side of SE 192nd Street;
On-grade paved trail starts approximately 200 feet east of the intersection of SE 192nd Street
and 124th Avenue SE. The trail extension continues both east and west from this point,
terminating at the pedestrian crosswalk for the Meeker Middle School to the east. The trail
continues west 124th Avenue SE before turning north;
A retaining wall along the east side of 124th Avenue SE, approximately 500 feet north of the
intersection of SE 192nd Street and 124th Avenue SE. The proposed wall will have a maximum
height of 6 feet;
A retaining wall along the northeast side of the proposed trail alignment near SE 186th Street
with a maximum height of 4 feet; and
New signal pole on the north side of SE 192nd Street, about 200 feet east of the intersection of
SE 192nd Street and 124th Avenue SE.
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4. Subsurface Conditions
Our understanding of the subsurface is based on conditions encountered in our explorations, as well as
our review of available regional geology in the site area. In general, soil conditions consist of variable
depths of fill consisting of loose to medium dense silty sand, over medium stiff to stiff silt and clay or
dense poorly graded sand with silt. We provide a more detailed description of the observed soil
conditions in the following sections of this report. The approximate locations of explorations performed
for this study are shown on Figure 2.
The explorations referenced in this study reveal subsurface conditions only at discrete locations across
the project site, the actual conditions in other areas may vary. Furthermore, the nature and extent of
any such variations would not become evident until additional explorations are performed or until
construction activities are underway. If significant variations are observed at that time, we may need to
modify our conclusions and recommendations accordingly to reflect actual site conditions.
4.1 LOCAL GEOLOGY
According to the Washington Interactive Geologic Map (DNR, 2023), the surface geologic unit map at
the site is generally in Pleistocene continental glacial drift. Pleistocene continental glacial drift is
generally composed of till and outwash with clay, silt, sand, and gravel, generally in a very dense/hard
condition. Our explorations generally encountered this condition, but beneath the more recently placed
alluvial and fill deposits described herein.
4.2 SOIL CONDITIONS
Haley & Aldrich completed five test pits, HA-TP1 to HA-TP5, to depths of up to 12.5 feet below ground
surface (bgs) on 31 January 2025. We also completed five borings, HA-B1 to HA-B5, from 17 February
2025 to 20 February 2025. These borings were advanced to depths of 13.5 to 61.5 feet bgs. Boring
HA-B1 encountered early drilling refusal at a depth of 13 feet bgs. Efforts to further advance the boring
were unsuccessful, likely due to a shallow obstruction. HA-B2 was advanced to a depth of 61.5 feet, and
then a grouted-in-place vibrating wire piezometer (VWP) was installed at a depth of 12 feet. A data
logger was placed within a flush-mounted monument to allow for continuous groundwater recordings to
be taken.
To better visualize and understand the subsurface conditions at the project site, we present subsurface
profiles designated A-A’ and B-B’ on Figures 4 and 5. The locations of these cross-sections are shown on
Figure 3.
The soil layers observed during the field explorations program were broadly categorized into
engineering soil units (ESUs) based on their engineering properties. In general, the soils observed in the
explorations consist of the soil units described below:
ESU 1 - Fill. The site is generally underlain by a layer of fill, up to 5 feet thick, consisting of a
mixture of very loose to medium dense sands with varying amounts of silt and fines.
ESU 2 - Organic Soil. Underlying the surficial fill is an approximate 0.5- to 2.5-feet-thick layer of
an organic soil along SE 192nd Street, consisting of loose, dark brown silt with roots. From our
laboratory tests, the organic contents in ESU 2 range from 10 to 18 percent. According to Table
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5 in Naval Facilities Engineering Command (NAVFAC) Soil Mechanics Design Manual (DM) 7.01
(1986), organics soils are classified with organic content of 5 percent to 30 percent. Based on
this and our laboratory test results, ESU 2 is generally considered as organic fine-grained soil.
The organic soil was not encountered along 124th Avenue SE during our explorations.
ESU 3 - Alluvium. Beneath the fill or organic soil, Alluvium was encountered with thicknesses of
approximately 5 to 20 feet, consisting of medium dense sand with varying amounts of silt or
medium stiff to stiff silt with sand. Our explorations and analysis suggest this unit to be
susceptible to liquefaction when within the wetland area along SE 192nd Street, as discussed in
Section 5.3.2.
ESU 4 - Glacial Drift (Till or Outwash). Dense to very dense sand with varying amounts of silt or
stiff to hard clay was encountered underlying the Alluvium soil. These glacial drift soils were
generally characterized by higher penetration resistances.
The conditions encountered in our explorations are presented in boring and test pit logs in Appendix A.
The test results for grain size analyses, Atterberg limits, and organic tests for selected samples, are
presented in Appendix B.
Note that subsurface conditions were interpreted from explorations completed at discrete locations
across the site; actual conditions in other areas could vary. We have noted variable soil types that have
been grouped into general soil units for simplicity on cross sections and for discussion in sections below.
The variability of the soil and the tendency for gradational changes within similar soil units required a
degree of interpretation and generalization. The nature and extent of variations between explorations
may not become evident until construction.
4.3 GROUNDWATER CONDITIONS
The five exploration borings HA-B1 through HA-B5 encountered groundwater between 4.5 and 9.2 feet
bgs at the time of drilling, as shown in Table 1, below. No groundwater was encountered in the test pits,
except HA-TP3. Seepage was observed at HA-TP3 at approximately 10 feet bgs (Elevation 375.9 feet in
NAVD 88). Based on the more recent groundwater readings from VWP in the monitoring well (HA-B2) on
10 March 2025, the highest groundwater table was observed to be about 4.0 feet bgs (Elevation
373.6 feet). See Table 1, below, for groundwater measurements.
Table 1. Groundwater Depths and Elevations During Our Explorations and Groundwater Monitoring
Boring Date Boring
Completed
ATD Water
Level
Depth
(feet bgs)a
ATD Water Level
Elevation
(feet NAVD
88)a
Monitoring
Dates Period
VWP
Depth
Groundwater
Depth Range
(feet bgs)
Groundwater
Elevation Range
(feet, NAVD 88)
HA-B1 19 February
2025 4.5 372.4 N/A
HA-B2 17 February
2025 7.6b 369.9 20 February to
10 March 2025 12 4.0 to 4.5 373.1 to 373.6
HA-B3 18 February
2025 7.2 370.4
N/A
HA-B4 19 February
2025 6.1 373.7
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Table 1. Groundwater Depths and Elevations During Our Explorations and Groundwater Monitoring
Boring Date Boring
Completed
ATD
Water
Level
Depth
(feet bgs)a
ATD Water
Level
Elevation
(feet NAVD
88)a
Monitoring
Dates Period
VWP
Depth
Groundwater
Depth Range
(feet bgs)
Groundwater
Elevation Range
(feet, NAVD 88)
HA-B5 20 February
2025 9.2 377.2
HA-TP3 31 January
2025 10 375.9.
Notes:
a. ATD = At Time of Drilling
b. Measurement taken prior to well development, and may not be representative of steady state.
Based on the groundwater during drilling and monitoring, we recommend assuming a static design
groundwater elevation 374 feet along SE 192nd Street and elevation 377 feet along 124th Avenue SE.
Groundwater levels noted above are representative of the time of observations. Variation in
groundwater level should be expected depending on location, season, precipitation, and other factors.
For planning purposes, we recommend assuming the possibility of encountering perched groundwater
during construction. It should be noted that groundwater management needs will depend on field
conditions encountered at the time of construction.
4.4 CORROSION TEST RESULTS
We submitted one composite soil sample (HA-B2, G-1 as identified by testing lab) from soil spoils
between 0 to 20 feet bgs to HWA Geosciences, Inc (HWA) to evaluate the corrosion potential. pH,
resistivity test, sulfate, and chloride testing were conducted. Testing results are summarized below in
Table 2 and included in Appendix B. This information is provided for the structural engineer to perform
their corrosion evaluation.
Table 2. Corrosion Test Results
Parameters Results
Nonaggressive Soil
Criteria Provided in
AASHTO LRFD
Specifications
pH 7.0 5 to 10
Soil Resistivity (ohm-cm) 2,100 ≥ 3,000
Chloride (mg/kg) 58 ≤ 100
Sulfate (mg/kg) 4 ≤ 200
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5. Seismic Considerations and Recommendations
The seismicity of western Washington is dominated by the Cascadia Subduction Zone, in which the
offshore Juan de Fuca Plate is subducting beneath the continental North American Plate. Three main
types of earthquakes are typically associated with subduction zones: crustal, interface subduction, and
intraslab subduction.
Crustal Sources. Recent fault trenching and seismic records in the Puget Sound area clearly indicate a
distinct shallow zone of crustal seismicity, the Seattle Fault Zone (SFZ), which may have surficial
expressions and can extend 25 to 30 kilometers deep.
Subduction Zone Sources. The offshore Juan de Fuca Plate is subducting below the North American
Plate. This causes two distinct types of events. Large-magnitude interface earthquakes occur at shallow
depths near the Washington coast (e.g., the 1700 earthquake with magnitude of 8 to 9) at the interface
between the two plates. A deeper zone of seismicity is associated with bending the Juan de Fuca Plate
below the Puget Sound region that produces intraslab earthquakes at depths of 40 to 70 kilometers
(e.g., the 1949, 1965, and 2001 earthquakes).
5.1 SITE SOIL CLASS FOR SEISMIC DESIGN
Haley & Aldrich determined the soil site class using information about the supporting foundation soils in
accordance with the American Society of Civil Engineers (ASCE) Standard, ASCE 7-16 (ASCE, 2017). The
soil site class is determined considering the soil characteristics and a weighted average of the blow
counts observed to a depth of 100 feet bgs. For explorations advanced less than 100 feet bgs, we
assumed the material density below the deepest sample remains constant to 100 feet to determine the
site class. This is a conservative assumption given the very dense glacially overridden soils encountered
at the end of our borings typically increase in density with depth.
Boring logs of explorations performed for the project generally indicate a Site Class D.
5.2 DESIGN SEISMIC PARAMETERS
Haley & Aldrich understands the seismic design of the proposed trail will be in accordance with seismic
design considerations established by American Association of State Highway and Transportation Officials
(AASHTO,2024). The basis of design in AASHTO is an earthquake with a 7-percent probability of
exceedance in 75 years, which corresponds to an average return period of 1,000 years.
The mapped parameters (ASCE Hazard Tool) consist of a peak ground acceleration and 5-percent
damped spectral accelerations at periods of 0.2 and 1.0 second, based on a probabilistic seismic hazard
analysis the U.S. Geological Survey performed across the United States. The mapped values correspond
to a site shear wave velocity of 2,500 feet per second corresponding to a soft rock/hard soil site (Site
Class B/C boundary) and must be modified to account for site soil conditions represented by site class.
The mapped seismic parameters and site coefficients corresponding to seismic Site Class D are used to
modify the mapped ground motion hazard to account for site conditions. Seismic design parameters are
presented in Table 3.
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Table 3. AASHTO Seismic Design Parameters
Parametersa Value
Latitude 47.4303
Longitude –122.1746
Site Class D
Spectral Response Acceleration at Short Periods, SS 0.939
Spectral Response Acceleration at 1-second Periods, S1 0.268 g
Mapped Peak Ground Acceleration (PGA) 0.448 g
Site Coefficient for Short Period Spectral Response Acceleration SS, Fa 1.124
Site Coefficient for 1-second Period Spectral Response Acceleration, Fv 1.863
Site Coefficient for mapped PGA, FPGA 1.088
Note:
a. Values in this table are for use in design based on AASHTO.
5.3 SEISMICALLY INDUCED GEOTECHNICAL HAZARDS
Our assessment of seismic hazards at the project site is based on the soil explorations in this report,
regional experience, and our knowledge of local seismicity. The potential hazards include surface
rupture, liquefaction and subsidence, and lateral spreading.
5.3.1 Surface Rupture
The SFZ consists of multiple east-trending, north-verging reverse-thrust faults located in the Puget
Lowlands of western Washington. The southernmost splay of the Seattle Fault is estimated to be
approximately 5.5 miles northeast of the site. Because there appear to be no significant faults
underlying the site, the hazards associated with surface rupture at the site is considered very low.
5.3.2 Liquefaction and Subsidence
When cyclic loading occurs during a seismic event, the shaking can increase the pore pressure in loose to
medium dense saturated sand and cause liquefaction, resulting in temporary loss of soil strength that
can lead to surface settlement. Site borings encountered appreciable contiguous loose to medium dense
saturated sand below the groundwater table. We performed liquefaction analysis based on Idriss and
Boulanger (2008) as well as Bray and Sancio (2006) for all standard penetration test samples taken at
the site. Our analysis indicated ESU 3B to be generally susceptible to liquefaction between depths of
10 and 20 feet along 192nd Street SE. Additionally, our analysis indicated the site fill (ESU 1) to be
liquefiable when below the groundwater table. We note that the fill we explored was above the
measured groundwater table and we generally consider this unit not susceptible to liquefaction as a
result.
For liquefiable samples, we estimated the liquefaction-induced settlements following Idriss and
Boulanger (2008). Our analysis estimated settlements at HA-B2 and HA-B3 to be generally up to
2 inches.
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5.3.3 Lateral Spreading
Lateral spreading is typically associated with lateral movement on sloping ground caused by shear strain
accumulation during cyclic loading or by reduction of shear strength of soil within or under the slope.
Because the liquefaction hazard is low and our site generally contains vertical relief less than 6 feet, the
lateral spreading hazard is also low.
6. Geotechnical Analysis and Recommendations
This section discusses geotechnical design considerations for the trail alignment. Our recommendations
are based on our current understanding of the project and on our subsurface explorations at discrete
locations, and laboratory tests. If the nature or location of the trail is different than we assumed or if
different subsurface conditions are observed during construction, we should be notified so we can
confirm or modify our recommendations to reflect current project or actual site conditions.
6.1 DEEP FOUNDATION DESIGN
Deep foundation design recommendations are needed for two structures on the project:
New signal pole foundation; and
New boardwalk on the north side of 192nd Street.
Haley & Aldrich understands the signal pole will likely consist of a cantilevered pole structure. In our
experience, these structures have high moment demands that require larger diameter shaft foundations
or more robust steel pipe sections. Typically, we see 2- to 3-foot-diameter drilled shafts or larger
diameter steel pipe piles on the order of 24 inches. The boardwalk structure will have relatively small
vertical loads that can be supported by smaller diameter sections. In our experience, micropiles, helical
piles, or small-diameter pipe piles work well in this situation. However, we understand the
environmental permits for the project preclude the placement of “fill” material in the wetland, which
would include wet grout or concrete needed for a shaft or micropile operation. Therefore, we only
include recommendations for driven steel elements in this report.
The final foundation system will be based on the structural engineer’s analysis, considering
compression, tension, and lateral demands on the deep foundation elements. The following sections
present our geotechnical recommendations to support the structural engineer’s analysis.
6.1.1 Deep Foundation Subsurface Design Profile
Haley & Aldrich conservatively generalized our subsurface design profile (Figure 4 – Cross Section A-A’)
based on the deepest contact of the very dense glacial till unit. The profile is summarized in Table 4 and
5, below, for the piles supported boardwalk and signal pole, respectively. Note: we did not include
considerations for the fill encountered in our borings, as the boardwalk and signal pole will be installed
to the north of the fill embankment where our borings were advanced.
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Table 4. Design Soil Profiles at the Piles Supported Boardwalk
Engineering
Soil Unit
Estimated
Elevation of
Engineering Soil
Unit (feet)
Soil
Type
Effective
Unit
Weighta
(pcfb)
Friction
Angle
(degree)
Soil Modulus, K
(pcic)
P-Multiplier
(liquefied)
ESU 2 (Above
Groundwater
Table)
Ground surface
to 374 feet API Sand 70 20 5 NA
ESU 2 (Below
Groundwater
Table)
374 to 368 feet API Sand 7.6 20 5 NA
ESU 3 368 to 343 feet API Sand 47.6 34 68 0.1
ESU 4 Below 343 feet API Sand 67.6 38 122 NA
Notes:
a. When the soil mass is below groundwater table, it is subjected to the force of buoyancy and the total unit weight soil is
reduced by unit weight of water (62.4 pcf).
b. pcf = pounds per cubic feet
c. pci = pounds per cubic inch
Table 5. Design Soil Profiles at the Signal Pole
Engineering
Soil Unit
Estimated
Elevation of
Engineering Soil Unit (feet)
Soil Type
Effective
Unit
Weighta (pcfb)
Friction
Angle
(degree)
Soil Modulus, K
(pcic)
P-Multiplier
(liquefied)
ESU 1 Ground surface to
374 feet API Sand 130 32 72 NA
ESU 2 374 to 368 feet API Sand 7.6 20 5 NA
ESU 3 368 to 343 feet API Sand 47.6 34 68 0.1
ESU 4 Below 343 feet API Sand 67.6 38 122 NA
Notes:
a. When the soil mass is below groundwater table, it is subjected to the force of buoyancy and the total unit weight soil is
reduced by unit weight of water (62.4 pcf). b. pcf = pounds per cubic feet
c. pci = pounds per cubic inch
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The anticipated depths to the different soil units were estimated based on a straight-line extrapolation
of the contacts between adjacent borings. Actual conditions may vary in the field.
6.1.2 Deep Foundation Axial Resistance
Nominal single-pile resistances were calculated using methods outlined in the Section 10.7 of AASHTO
LRFD (2024). We have primarily assumed the boardwalk piles will consist of 12-inch-diameter, open-
ended, steel pipe piles and the signal pole foundation will consist of a 24-inch-diameter open-ended,
steel pipe pile for the 50% design. Our analyses assume the open-ended piles are “unplugged” during
driving.
We present our axial resistance recommendations for 12-inch and 24-inch steel pipe piles in Appendix C.
Additional charts can be provided for the final design. The resistance charts (Appendix C, Figures C-1 and
C-2) show curves for nominal (unfactored) strength limit state and nominal extreme event limit state
conditions. According to Table 10.5.5.2.3-1 in AASHTO LRFD (2024), recommended resistance factors are
presented in Table 6, below.
Table 6. AASHTO LRFD (2024) Resistance Factors for Single-Driven Pipe Pile
Limit State Tip
Resistance
Side Resistance
(Compression)
Side Resistance
(Uplift)
Strength Limit State 0.4 0.4 0.25
Extreme Event Limit State (Seismic) 1.0 1.0 0.8
Pile group effects should be accounted for in accordance with Sections 10.7.3.9 and 10.7.3.11 of the
AASHTO LRFD (2024). Subsurface conditions primarily consist of cohesionless soils overlying very dense
glacial drift layers; therefore, cohesionless soil conditions will be considered for pile group effects in
compression and uplift. For center-to-center pile spacing greater than 6 pile diameters, the full axial
capacity of the pile may be used prior to load and resistance factoring. For center-to-center pile spacing
less than 2.5 pile diameters, a strength reduction factor of 0.65 should be applied to the axial pile
capacity prior to load and resistance factoring. For intermediate spacings, linear interpolation of the
axial capacity factor may be used.
6.1.3 Deep Foundation Seismic Displacement and Downdrag
As discussed above, the medium dense Alluvial deposits (ESU 3) are expected to undergo settlements of
up to 2 inches due to liquefaction, as discussed in Section 5.3.2. Post-liquefied differential settlements
could be up to 2 inches between zones of liquefiable and non-liquefiable soils. We recommend assuming
differential settlement of approximately 2 inches across 80 feet.
Downdrag is a phenomenon generally caused by differential movement between a deep foundation
element and the surrounding soil mass. When the soil settles more than the displacement of the pile,
downdrag forces are mobilized along the length of the pile, adding to the overall pile demand. For piles
installed within a liquefiable layer (i.e., tip elevation within the zone of liquefaction), downdrag forces
can be negligible as the pile settles with the surrounding soil. When deep foundations are tipped into
non-liquefiable material beneath the settling soil mass, downdrag loads would be expected to be fully
mobilized.
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Liquefaction-induced downdrag loads on 12- and 24-inch-diameter pipe piles were calculated to be
approximately 18 and 37 kips, respectively, as noted on the figures in Appendix C. These downdrag
forces should be added to the structural loads for the piles immediately after seismic shaking, though do
not need to be coupled with seismic inertial forces.
6.1.4 Deep Foundation Lateral Resistance
Lateral resistance of the driven piles shall be in accordance with Section 10.7.3.12 of AASHTO LRFD
(2024). We recommend that P-y curves be generated using the computer program LPile developed by
Ensoft, Inc. using the model parameters for each soil unit as outlined in Table 4, above, for piles farther
apart than 8B, where B is the pile diameter.
Should the piles be spaced closer than 8B, lateral group effects should be considered in accordance with
Section 10.7.2.4 of the AASHTO LRFD (2024). Table 7, below, outlines P-multiplier values, (Pm). Pile group
effects should be accounted for Appropriate P-multipliers (Pm) will need to be applied to P-y curves
based on group geometry and direction of applied loads.
Table 7. Pile P-Multipliers, Pm, for Multiple Row Shading (averaged from Hannigan et al., 2006)
Pile CTCa Spacing (in the
direction of loading)
P-Multipliers, Pm
Row 1 Row 2 Row 3 and higher
3B 0.8 0.4 0.3
5B 1.0 0.85 0.7
8B 1.0 1.0 1.0
Note:
CTC: Center to center
6.1.5 Considerations for Pile Length
Haley & Aldrich recommends additional pile length be incorporated into the pile schedule for bidding
and procurement purposes. Inherent uncertainty in our analysis exists that may manifest during
construction in variable final embedment lengths to meet the required design criteria. Additional pile
length may be cut off more economically than spliced on during construction. Therefore, we
recommend a minimum of 5 extra feet be added to each pile.
6.2 MODULAR BLOCK WALL
We understand two modular block walls are planned to support the trail along 124th Avenue SE. We
performed global stability analyses on the most critical section at Section 17+00 from the “Proposed
Sections” drawings, dated 25 February 2025, shared by Huitt Zollars. Also, based on the “Proposed
Section” (Huitt Zollars, 2025), the proposed wall height for the northern most wall is generally less than
4 feet. According to Washington Administrative Code (WAC) 51-16-080, retaining walls that are less than
4 feet in height do not require formal design, including global stability analysis.
6.2.1 Global Stability Methods
We completed slope stability analyses using the SLIDE software package (Rocscience, 2023), which uses
limit equilibrium methods. Limit equilibrium methods assume shear failure along a potential slip surface
and calculate driving and resisting shear forces along that surface based on input soil parameters,
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topography, and groundwater levels. The resisting forces divided by the driving forces are the factor of
safety (FS) against sliding along a given slip surface. FS are computed for various slip surfaces to
determine the controlling, or critical, case. The computations used non-circular search methods,
methods using force and moment equilibrium (i.e., Spencer and Morgenstern-Price analysis methods).
Generally, minimum static (strength and service limit states) and seismic (extreme limit state) slope
stability FS of 1.5 and 1.1 are typically used as appropriate design criteria for trail projects, which follows
the guidelines in the Section 7.4 of Washington State Department of Transportation (WSDOT)
Geotechnical Design Manual (GDM) (WSDOT, 2022).
6.2.2 Soil Properties
The site soil stability parameters are presented in Table 8, below, and are based on empirical
correlations to Standard Penetration Test data (e.g., blow counts) in HA-B1 to HA-B5, Haley & Aldrich’s
experience with similar soils in similar geologic settings, and WSDOT GDM Section 5.8.3 (WSDOT, 2022).
Table 8. Slope Stability Model Soil Parameters
Soil Descriptions Total Unit Weight (pcf) Friction Angle (degrees) Cohesion (psfa)
Fill 120 32 0
Alluvium 125 36 0
Till 130 38 0
Gravel Backfill 125 38 0
Notes:
a. psf = pounds per square foot
6.2.3 Groundwater
Groundwater was modeled at about an elevation of 377 feet, which is based on the groundwater
encountered during Haley & Aldrich’s explorations at HA-B5 and HA-TP3, at about elevations of 377 and
376 feet, respectively. Groundwater was not encountered in the rest of the explorations along 124th
Avenue SE.
6.2.4 Global Stability Results
Slope stability was analyzed using the methods, inputs, and assumptions described previously in this
section. The stability analysis figures are included in Appendix D showing the soil layers, topography,
groundwater level, and resulting slip surfaces for static (strength and service limit states) and seismic
(extreme limit state) loadings. The results for static and seismic conditions indicate the proposed
modular block wall has a FS of 2.0 and 1.1, which meets and exceeds the target FS of 1.5 and 1 required
by WSDOT GDM, respectively. In order to reach a FS of 1.1 in the seismic condition, the native soil
behind the proposed wall needed to be replaced with competent structural fill.
We recommend overexcavating and replacing the native soils with structural fill along the length of the
wall. We recommend requiring overexcavation following a 2H:1V projection to the ground surface from
the bottom of the backside of the wall and a 1.5H:1V projection to the ground surface from the base
and in front of the wall. The structural fill material should generally consist of imported fill as defined in
Section 7.2.1 below.
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6.2.5 Wall Design Recommendations
It is typically economical for the vendor of the wall materials to design the modular block wall for
internal stability, with our input and review. We recommend the following for modular block wall
design:
Design the modular block walls in general accordance with the Federal Highway Administration
(FHWA) design manual, Mechanically Stabilized Earth Walls and Reinforced Soil Slope Design
and Construction Guidelines (FHWA, 2001).
Use a soil friction angle of 38 degrees and a unit weight of 130 pcf for the compacted structural
fill that makes up the modular block wall. These values assume the use of WSDOT Gravel Backfill
for walls, free of organic material, placed and compacted to a minimum of 95 percent of the
maximum dry density. The frictional strength of the fill material will need to be determined early
in the modular block wall design stage. Soil properties should be confirmed, and the design
modified, if necessary, once actual fill materials are identified.
For lateral earth pressure acting on the reinforced soil prism of the modular block wall system,
use an equivalent fluid density (EFD) of 35 pcf, assuming level backfill and active pressure
conditions for yielding wall systems (minimum wall movement 0.001 times the height of the
wall).
For the sliding resistance between the base of the modular block wall and foundation soil, use
an allowable coefficient of friction of 0.3(with a resistance factor of 0.67).
To improve stability and reduce risk of future erosion, use a minimum wall embedment depth of
2 feet below the ground surface.
We recommend retaining Haley & Aldrich to review the modular block wall designer’s design
calculations, specifications, and plans for conformance with geotechnical recommendations. See Section
6.2.4 above for analyzed global stability for the modular block wall system.
6.3 TEMPORARY AND PERMANENT WALL DRAINAGE
To provide adequate drainage and reduce the risk of hydrostatic pressure on the modular block wall, the
wall backfill should consist of free-draining sand or sand and gravel with less than 5 percent by weight
passing the U.S No. 200 mesh sieve, based on the minus 3/4-inch fraction of the material. If excavated
on-site soil (which may not be free-draining) will be used within the wall backfill zone, we recommend
placing a curtain drain of at least 18 inches of imported, free-draining soil directly behind the face
blocks, and as a blanket drain behind the reinforced soil zone. Gravel backfill for walls, as described in
WSDOT Standard Specifications, Section 9-03.12(2), with the added requirement that fines content
should not exceed 5 percent (based on the minus 3/4-inch fraction of the material) may be used for this
purpose.
6.4 ON-GRADE TRAIL PAVEMENT
We understand that the on-grade portions of the trail will have an asphaltic concrete pavement (ACP)
surface. The planned pavement section can likely be supported on the near-surface soils anticipated
along most of the alignment, provided that the soils are primarily granular (i.e., silty sand, sand, and/or
gravel) and that the trail subgrade areas are prepared as recommended in this report. However, we
were not able to perform explorations from STA 16+00 to the north-end of the proposed trail due to
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lack of site access; so, site conditions will likely vary. A Haley & Aldrich representative should be on site
during construction to assess the required stripping depth during construction. If moisture-sensitive,
fine-grained soils (i.e., sandy silt, silt, or clay) are encountered in pavement subgrade areas, it may need
to be overexcavated up to 2 feet bgs and replaced with geogrid (MIRAFI 1100N or similar) and structural
fill, if found to be yielding during proof rolling, as discussed in Section 7.1.
Assuming well-compacted, granular fill soil or structural fill subgrade, the asphalt pavement section of
the on-grade trail should consist of 2 inches of ACP over 4 inches of crushed surfacing base course
(CSBC) for light-duty traffic, including occasional emergency vehicles. Class B asphalt is typically suitable
for ACP courses. The CSBC layer should consist of imported crushed surfacing top course or base course,
according to WSDOT Standard Specifications, Section 9-03.9(3). We generally recommend against the
use of recycled or pulverized concrete as CSBC.
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7. Construction Recommendations
7.1 SITE PREPARATION AND GRADING
The trail alignment generally runs through areas that are currently undeveloped, except for the
proposed trail alignment along 124th Avenue SE, approximate from STA 12+50 to STA 16+00, where the
historical fill is up to approximately 5 feet bgs. Initial site preparation will involve stripping and grubbing
existing vegetation and visible organic material and overexcavating unsuitable soils. We estimate that
the stripping depth will vary from less than a foot up to a few feet, depending on the thickness of root
material and organic matter at specific locations. Generally, visible organic material (sod, humus, roots
larger than 1/4 inch in diameter, and/or other decaying plant material), debris, and other unsuitable
materials should be removed from the subgrade areas. Material in areas of historical fill will be highly
variable.
Along most of the alignment, topsoil, grass, or asphalt was typically encountered to a depth of 2 inches
to 12 inches; organic soil and unsuitable fill material was encountered in variable amounts below this
depth in several borings and test pits.
Site preparation should provide a firm and unyielding subgrade beneath on-grade trail portions,
retaining walls, and embankment fill areas. Structural or pavement subgrade areas should be compacted
to a firm and unyielding surface and should be observed and approved by a Haley & Aldrich
representative. Specific pavement subgrade preparation includes removal of surficial organic material
and compaction of near-surface granular subgrade soil to a minimum density of 95 percent of the
maximum dry density as determined by the modified Proctor method (ASTM D1557). The subgrade
should then be proof rolled with a loaded dump truck to verify a firm and unyielding subgrade. Any
localized zones of yielding subgrade disclosed during proof rolling should be overexcavated to a depth to
be determined in the field, and replaced with compacted structural fill (granular subbase course) for
pavement or suitable large-aggregate material such as quarry spalls, riprap, or ballast rock for others. A
suitable geofabric may be required to stabilize the soft subgrade below the overexcavation and
minimize silt migration into the structural fill and pavement section, based on a field evaluation of
subgrade conditions. Overexcavation below footing or pavement subgrade areas should extend a
distance outside the edge of the footing or pavement equal to the depth of the overexcavation.
It may be necessary to relocate or abandon some utilities within the construction area. Abandoned
underground utilities should be removed or completely grouted. The ends of remaining abandoned
utility lines should be sealed to keep soil and water out. Soft or loose backfill materials should be
removed, and the area backfilled according to the structural fill recommendations in this report.
Coordination with the utility owners is generally required when addressing existing utilities.
Any existing concrete elements that are encountered should be removed if they are within 2 feet
vertically of the bottom of pavement sections. The purpose of this is to eliminate “hard spots” that could
lead to “bumps” in the trail surface.
7.2 STRUCTURAL AND COMPACTED FILL
Structural fill is required for backfill in open cut and overexcavated areas, beneath pavement, behind
retaining walls, and above utility installations. The suitability of soil for structural fill depends primarily
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on its grain size distribution and moisture content when placed. As the fines content (fraction passing
the U.S. No. 200 mesh sieve) increases, soil becomes more sensitive to small changes in moisture. With
more than about 5 percent fines (by weight), soil cannot be consistently compacted to a firm, relatively
unyielding condition when the moisture content is more than 2 percent above or below optimum
moisture content as determined from the Modified Proctor test. Structural fill must also be free of
organic matter and other debris.
Generally, any fill material with moisture content at or near optimum can be compacted as structural fill
provided it is placed on a firm and relatively unyielding subgrade surface. However, if fill is to be placed
during wet weather, we recommend using clean fill, that is, soil with a fines content (fraction passing the
U.S. No. 200 mesh sieve) of 5 percent or less (by weight).
For structural fill placement and compaction, we recommend:
Place and compact all structural fill in lifts with a loose thickness no greater than 8 to 10 inches.
If small hand-operated compaction equipment is used to compact structural fill within 12 inches
of utility pipes or other structures, the lifts should not exceed 4 to 6 inches in loose thickness,
depending on the equipment used. The maximum particle size within the structural fill should
be no more than two-thirds of the loose lift thickness to allow full compaction of the soil
surrounding the large particles.
Generally, compact structural fill that is beneath footings, behind walls, and within 2 feet of the
bottom of pavement sections to a minimum of 95 percent of the modified Proctor maximum dry
density, as determined by the ASTM D1557 test procedure.
Structural fill that is more than 2 feet below pavement sections, and within 2 feet of the back of
subgrade walls should be compacted to 92 percent of the modified Proctor maximum dry
density.
Within 2 feet of subgrade walls, use hand compaction equipment to avoid overstressing the
wall.
Control the moisture content of the fill to within 2 percent of the optimum moisture based on
laboratory Proctor tests. The optimum moisture content corresponds to the maximum
attainable Proctor dry density.
Generally, place structural fill only on dense and relatively unyielding subgrade (see Section 7.1).
If subgrade areas are wet, clean material with at least 30 to 35 percent gravel content (material
coarser than a U.S. No. 4 mesh sieve) may be needed to bridge moisture-sensitive subsoils. In
some cases, clean crushed rock or quarry spalls may be needed to stabilize weak or wet
subgrade soil.
Where free-draining material is required, such as behind retaining walls or around drainage
pipes, use a well-graded sand and gravel with less than 3 percent passing the U.S. No. 200 mesh
sieve (based on the minus 3/4-inch fraction of the material).
Perform a representative number of in-place density tests to verify adequate compaction. A
Haley & Aldrich representative should verify each structural fill lift and the subgrade area below
it.
Before using any material as structural fill, have it sampled and tested to determine its
maximum dry density and gradation.
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7.2.1 Imported Structural Fill
Generally, imported structural fill for most applications should meet the requirements for Gravel Borrow
in 2024 WSDOT Standard Specifications, Section 9-03.14(2) (WSDOT, 2024). Imported structural fill
should be well-graded sand or sand and gravel with a low fines content, free of organic and other
unsuitable materials.
7.2.2 Use of Site Soil as Structural Fill
In general, the site soils may not be suitable for reuse as structural fill. Much of the near-surface soil
(below surficial organics) encountered in our explorations was moist granular soil with relatively high silt
content and is not suitable for use as structural fill or re-compaction, given favorable weather and
moisture conditions. Most of the soil samples contained more than 5 percent fines and would thus be
moisture-sensitive; such soils are difficult to compact if they are wet when excavated, become wet when
stockpiled, or are placed during wet weather.
Because the soils along the trail alignment vary, as will the weather, the suitability of on-site soils for use
as structural fill should be determined in the field during construction. We recommend separately
stockpiling the excavated soil intended for reuse as structural fill and having the on-site geotechnical
engineer or geologist review it for suitability. Stockpiles should be protected with plastic sheeting so
they do not get overly wet during rainy weather. On-site soil is typically not considered suitable for use
as free-draining material, unless a large deposit of consistently clean (silt-free) sandy soil is found.
7.3 PERMANENT SLOPES
Permanent cut and fill slopes should be adequately inclined and revegetated to minimize long-term
raveling, sloughing, and erosion. A vegetative groundcover should be established as soon as possible
after grading, to further protect the slope from runoff-water erosion. Permanent slopes should not be
steeper than 2H:1V, to minimize long-term erosion and to facilitate revegetation. Final grading near the
top of permanent slopes should direct surface water away from the slope face for erosion and slope
stability perspectives.
7.4 TEMPORARY OPEN CUTS
Temporary soil cuts for site excavations more than 4 feet deep should be adequately sloped back to
prevent sloughing and collapse in accordance with Washington State Department of Labor & Industries
(L&I) Division of Occupational Safety and Health (DOSH) guidelines (WAC Chapter 296-155 Part N). The
stability and safety of cut slopes depend on a number of factors, including:
type and density of the soil;
presence and amount of any seepage;
depth of cut;
proximity and magnitude of the cut to any surcharge loads, such as stockpiled material, traffic
loads, or structures;
duration of the open excavation; and
care and methods used by the contractor.
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Because of the variables involved, slope angles required for stability in temporary cut areas can be only
estimated, not determined precisely, before construction. It is the contractor’s responsibility to ensure
the excavation is properly sloped or braced for worker protection in accordance with DOSH guidelines
and other applicable local or federal safety requirements.
Because soil conditions vary along the trail alignment, the contractor should anticipate encountering all
the soil types described in DOSH guidelines (Types A, B, and C), which may require temporary slope
inclinations ranging from 0.75H:1V to 1.5H:1V.
For planning purposes only, assume a temporary slope inclination of 1.5H:1V or flatter, until
actual soil conditions can be verified in the field during construction. If groundwater seepage is
encountered within the excavation slopes, the cut slope may need to be inclined flatter than
1.5H:1V.
Protect the slope from erosion with plastic sheeting for the duration of the excavation to reduce
the risk of surface erosion and raveling.
Limit the open excavation to the shortest time possible.
Place no surcharge loads (such as from equipment or materials) within 10 feet of the top of the
slope, in general. However, more or less stringent requirements may apply depending on field
conditions and actual surcharge loads.
Temporary or permanent cuts should not extend into existing steep slopes or bluffs near
portions of the proposed trail alignment, especially the steep hillside near the northern end of
the trail.
If adequate sloping or slot cutting is not feasible because of site spatial constraints or other factors,
temporary excavations should be supported by an appropriate shoring system
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8. Recommended Additional Geotechnical Services
Recommendations discussed in this report should be reviewed and modified as needed during the final
design stages of the project. We also recommend incorporating geotechnical construction observation into the construction plans.
8.1 GEOTECHNICAL CONSTRUCTION SERVICES
Because the future performance and integrity of the structural elements of the project will depend
largely on proper site preparation, drainage, fill placement, and construction procedures, monitoring
and testing by experienced geotechnical personnel should be an integral part of construction.
Our observations will verify compliance with design concepts and recommendations, and allow design
changes or evaluation of appropriate construction methods if subsurface conditions differ from those
anticipated before construction begins. We recommend retaining Haley & Aldrich, Inc. to provide the
following construction support services:
Review geotechnical-related construction submittals from the contractor to verify compliance
with the construction plans and the recommendations of this report.
Attend a pre-construction conference with the contractor and King County to discuss important
geotechnical-related construction issues.
Observe exposed wall footing, trail pavement, and embankment fill subgrade areas after
completion of excavation, to confirm that suitable soil conditions have been reached or
determine appropriate subgrade preparation methods, if needed.
Observe proof rolling of pavement subgrade before paving.
Observe installation of the deep foundations to confirm conformance with the geotechnical
design recommendations and construction plans.
Monitor the placement of and perform in-place density tests on structural fill soil to verify
conformance with construction specifications.
Observe installation of retaining wall and wall drainage to verify their conformance with
construction plans.
Observe excavation and construction of the slope setback along the trail segment.
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References
1. America Association of State Highway and Transportation Officials (AASHTO), 2024. LRFD Bridge
Design Specifications, 10th Edition.
2. American Society of Civil Engineers (ASCE), 2017,Minimum Design Loads and Associated Criteria
for Buildings and Other Structures, ASCE/SEI 7-16.
3. American Society of Civil Engineers (ASCE), ASCE Hazard Tool. https://ascehazardtool.org/
4. Bary, J.D. and R.B. Sanico, 2006. “Assessment of the Liquefaction Susceptibility of Fine-Grained
Soils” Journal of Geotechnical and Geoenvironmental Engineering, Volume 132, Issue 9, 1st
September.
5. Federal Highway Administration (FHWA) design manual, 2001,Mechanically Stabilized Earth
Walls and Reinforced Soil Slope Design and Construction Guidelines, Publication FHWA-NHI-00-
043, March.
6. Huitt Zollars, Inc., 2025. “Proposed Sections”, Issue date: February 25.
7. I.M. Idriss and R.W. Boulanger, 2008. “Soil Liquefaction During Earthquakes" Earthquake
Engineering Research Institute MNO-12.
8. Naval Facilities Engineering Command (NAVFAC), 1986, Soil Mechanics Design Manual (DM)
7.01. September 1
9. Rocscience Inc., 2023. Slide 2 Modeler, 2D Limit Equilibrium Analysis for Slopes, Build 9.031,
Build date: 8 November.
10. Washington Administrative Code (WAC), 2024. Section 51-16-080.
11. Washington State Department of Labor & Industries (L&I) Division of Occupational Safety and
Health (DOSH) guidelines, 2024, WAC Chapter 296-155, Part N.
12. Washington State Department of Natural Resources, Washington Geologic Information Portal
(DNR). https://www.dnr.wa.gov/geologyportal.
13. Washington State Department of Natural Resources, 2023. Online Natural Hazards and Coal
Mine Maps, viewed 2023. https://fortress.wa.gov/dnr/protectiongis/geology/.
14. Washington State Department of Transportation (WSDOT), 2022. Geotechnical Design Manual
M46-03.16, February.
15. WSDOT, 2024., Standard Specifications for Road, Bridges, and Municipal Construction M41-10.
https://haleyaldrich.sharepoint.com/sites/KingCountyParksRecreationDivision/Shared Documents/0207911.Soos Creek Trail Signal Pole/Deliverables/Soos Creek Trail Geotech Report_DRAFT/Draft_Revised/2025_0423_HAI_Soos Creek Trail Geotech Report_D.docx
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FIGURES
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WA
SITE
47°27'10"N
47°2'0"N
47°24'50"N
122°9'10"W122°10'20"W122°11'30"W
BASE MAP SERVICES
Ideal scales for
site vincity figures
1 : 108,000
Scale bar = 4 miles
1 : 54,000
Scale bar = 2 miles
1 : 24,000 (default)
1 : 13,500
Scale bar = 0.5 mile
GIS
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MAP SOURCE: ESRISITE COORDINATES: 47°25'57"N, 122°10'31"W
SOOS CREEK TRAIL SIGNAL POLE
RENTON, WASHINGTON
VICINITY MAP
FIGURE 1APPROXIMATE SCALE: 1 IN = 2000 FT
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LEGEND
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ALIGNMENT
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NOTES
1. ALL LOCATIONS AND DIMENSIONS ARE APPROXIMATE.
2. ASSESSOR PARCEL DATA SOURCE: KING COUNTY
3. DUE TO EXISTING VEGITATION (E.G. TREES, BUSHES)AND SLOPES, EXPLORATIONS COULD NOT BE PERFORMEDNORTH OF STA 17+00 AT THE TIME OF DRILLING
4. WETLAND BOUNDARY AND ALIGNMENT SOURCE: HUITT
ZOLLARS, FEBRUARY 2025
5. AERIAL IMAGERY SOURCE: NEARMAP, 1 AUGUST 2024
SOOS CREEK TRAIL SIGNAL POLE
RENTON, WASHINGTON
SITE AND EXPLORATION PLAN
STA 11+00 - STA 22+50
FIGURE 2APRIL 2025
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SCALE IN FEET
SOOS CREEK TRAIL SIGNAL POLE
RENTON, WASHINGTON
SITE AND EXPLORATION PLAN
STA 22+50 - STA 33+00
FIGURE 3APRIL 2025
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NOTES
1. ALL LOCATIONS AND DIMENSIONS ARE APPROXIMATE.
2. ASSESSOR PARCEL DATA SOURCE: KING COUNTY
3. DUE TO EXISTING VEGITATION (E.G. TREES, BUSHES)AND SLOPES, EXPLORATIONS COULD NOT BE PERFORMEDNORTH OF STA 17+00 AT THE TIME OF DRILLING
4. WETLAND BOUNDARY AND ALIGNMENT SOURCE: HUITT
ZOLLARS, FEBRUARY 2025
5. AERIAL IMAGERY SOURCE: NEARMAP, 1 AUGUST 2024
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DISTANCE IN FEET
300
320
340
360
380
400
300
320
340
360
380
400
-425 -400 -350 -300 -250 -200 -150 -100 -50 0
A'
WEST
A
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0
11
2
12
HA-B1
T.D.= 13.5
6
3
13
20
9
50/5"
50/3"
50/5"
50/5.5"
50/5"
50/5.5"
50/5.5"
83
50
HA-B2
T.D.= 61.5
9
1
11
12
19
15
50/6"
50/4.5"
50/2"
50/6"
89
(Proj. 6' S)
HA-B3
T.D.= 61.5
4
2
22
21
28
39
50/5.5"
50/3"
(Proj. 12' S)
HA-B4
T.D.= 30.8
0 40 80
SCALE IN FEET
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FIGURE 4
SOOS CREEK TRAIL SIGNAL POLE
RENTON, WASHINGTON
CROSS SECTION A-A'
APRIL 2025
LEGEND
ESU 1 - FILL
ESU 2 - ORGANIC SOIL
ESU 3A - ALLUVIUM (GRANULAR)
ESU 3B - ALLUVIUM (FINES)
ESU 4A - GLACIAL DRIFT (GRANULAR)
ESU 4B - GLACIAL DRIFT (FINES)
DESIGN GROUND WATER LEVEL
NOTE
THIS SUBSURFACE PROFILE IS GENERALIZED
FROM MATERIALS OBSERVED IN SOIL BORINGS
AND TEST PITS. VARIATIONS MAY EXIST BETWEEN
PROFILE AND ACTUAL CONDITIONS.
BORING LOCATION
BORING NAME
WITH OFFSET
22
B-1
(Proj. 92' S)
WATER LEVEL AT
TIME OF DRILLING
N-VALUE AND
COLLECTED
SAMPLE
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DISTANCE IN FEET
300
320
340
360
380
400
300
320
340
360
380
400
0 50 100 150 200 250 300 350 400 450 500
4
17
20
20
24
23
25
50/5"
HA-B5
T.D.= 30.5
(Proj. 6' SW)
HA-TP1
T.D.= 12.0
(Proj. 10' W)
HA-TP2
T.D.= 12.5
(Proj. 8' W)
HA-TP3
T.D.= 10.0
(Proj. 8' W)
HA-TP4
T.D.= 10.0
(Proj. 13' W)
HA-TP5
T.D.= 12.0
0 40 80
SCALE IN FEET
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FIGURE 5
SOOS CREEK TRAIL SIGNAL POLE
RENTON, WASHINGTON
CROSS SECTION B-B'
APRIL 2025
LEGEND
ESU 1 - FILL
ESU 2 - ORGANIC SOIL
ESU 3A - ALLUVIUM (GRANULAR)
ESU 3B - ALLUVIUM (FINES)
ESU 4A - GLACIAL DRIFT (GRANULAR)
ESU 4B - GLACIAL DRIFT (FINES)
DESIGN GROUND WATER LEVEL
NOTE
THIS SUBSURFACE PROFILE IS GENERALIZED
FROM MATERIALS OBSERVED IN SOIL BORINGS
AND TEST PITS. VARIATIONS MAY EXIST BETWEEN
PROFILE AND ACTUAL CONDITIONS.
BORING LOCATION
BORING NAME
WITH OFFSET
22
B-1
(Proj. 92' S)
WATER LEVEL AT
TIME OF DRILLING
N-VALUE AND
COLLECTED
SAMPLE
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APPENDIX A
Field Exploration Logs
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APPENDIX A
Field Explorations
This appendix documents the processes Haley & Aldrich, Inc. (Haley & Aldrich) used to determine the
nature of the soils at the project site, and contains the following sections:
Explorations and Their Locations;
Hollow-stem Auger and Mud Rotary;
Standard Penetration Test (SPT) Procedures;
In the Event of Hard Driving; and
Excavation of Test Pits.
EXPLORATIONS AND THEIR LOCATIONS
The exploration logs in this appendix show our interpretation of the excavation, sampling, and testing
data. The logs indicate the approximate depth where the soils change. The soil changes may be gradual
and may vary in depth across the site.
In the field, we classified the soil samples according to the methods shown on Figure A-1, Key to
Exploration Logs. The figure’s legend explains the symbols and abbreviations used on the logs.
Figure 2 shows the exploration locations based on measuring from existing features. Elevations are
referenced to the North American Vertical Datum of 1988 (NAVD88).
HOLLOW-STEM AUGER AND MUD ROTARY
Borings HA-B1 to HA-B5 were drilled with the hollow-stem auger and mud rotary technique from
17 February to 20 February 2025. These borings were advanced with a track-mounted drilling rig
subcontracted by Haley & Aldrich. Borings were advanced to depths ranging from about 13.5 to
61.5 feet below existing grades.
A Haley & Aldrich geologist or geotechnical engineer was on site to continuously observe the drilling.
Detailed field logs were prepared for the borings. Using SPT, we obtained samples at 2.5- and 5-foot
increments to the maximum depths explored. The boring logs are presented in this appendix.
STANDARD PENETRATION TEST PROCEDURES
The SPT (as described in ASTM International [ASTM] D 1586) is an approximate measure of soil density
and consistency. To be useful, the results must be interpreted in conjunction with other tests. The SPT
was used to obtain disturbed soil samples.
This test employs a standard 2-inch-outside-diameter split-spoon sampler. A 140-pound autohammer
free-falling 30 inches drives the sampler into the soil for 18 inches. The number of blows required to
drive the sampler the last 12 inches is the standard penetration resistance. This resistance, or blow
count, measures the relative density of granular soils and the consistency of cohesive soils. The blow
counts are plotted on the boring logs at their respective sample depths.
DR
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Soil samples were recovered from the split-spoon sampler, field classified, placed into watertight jars,
and taken to Haley & Aldrich’s laboratory for further testing.
IN THE EVENT OF HARD DRIVING
Occasionally, very dense materials preclude driving the total 18-inch sample. When this happens, the
penetration resistance is entered on logs as follows:
Penetration less than 6 inches. The log indicates the total number of blows over the number of
inches of penetration.
Penetration greater than 6 inches. The blow count noted on the log is the sum of the total
number of blows completed after the first 6 inches of penetration. This sum is expressed over
the number of inches driven that exceed the first 6 inches. The number of blows needed to drive
the first 6 inches is not reported. For example, a blow count series of 12 blows for 6 inches,
30 blows for 6 inches, and 50 (the maximum number of blows counted within a 6-inch
increment for SPT) for 3 inches would be recorded as 80/9.
EXCAVATION OF TEST PITS
Five test pits, designated HA-TP1 through HA-TP5, were excavated across the site on 31 January 2025,
with a backhoe subcontracted by our firm. The sides of these excavated pits offer direct observation of
the subgrade soils. The test pits were located by and excavated under the direction of an engineering
geologist from Haley & Aldrich. The geologist observed the soil exposed in the test pits and reported the
findings on a field log. Our geologist collected representative samples of soil types for testing at Haley &
Aldrich's laboratory. Groundwater levels or seepage were noted during excavation. The
density/consistency of the soils (as presented parenthetically on the test pit logs to indicate there having
been estimated) is based on visual observation only as disturbed soils cannot be measured for in-place
density in the laboratory.
The test pit logs are presented on A-7 through A-11.
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Figure A-1Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
Key to
Exploration Logs
Peat - Decomposing Vegetation -Fibrous to Amorphous Texture
Rock Core Run
Push ProbeThin-walled Sampler
%FAL
CACAUCCAUECBRCIDCCIUCCK0DC
CK0DSSCK0UC
CK0UECRSCNDSDSSDTGSHYD
ILCNK0CNkckfMDOCOT
PPID
PPSGTRSTVUCUUCVS
WC
Percent Passing No. 200 SieveAtterberg Limits (%)
Chemical AnalysisConsolidated Anisotropic Undrained CompressionConsolidated Anisotropic Undrained ExtensionCalifornia Bearing RatioConsolidated Drained Isotropic Triaxial CompressionConsolidated Isotropic Undrained CompressionConsolidated Drained k0 Triaxial Compression
Consolidated k0 Undrained Direct Simple ShearConsolidated k0 Undrained Compression
Consolidated k0 Undrained ExtensionConstant Rate of Strain ConsolidationDirect ShearDirect Simple ShearIn Situ DensityGrain Size ClassificationHydrometer
Incremental Load Consolidationk0 ConsolidationConstant Head PermeabilityFalling Head PermeabilityMoisture Density RelationshipOrganic ContentTests by Others
PressuremeterPhotoionization Detector Reading
Pocket PenetrometerSpecific GravityTorsional Ring ShearTorvaneUnconfined CompressionUnconsolidated Undrained Triaxial CompressionVane Shear
Water Content (%)
3.0" I.D. Split Spoon
Well Tip or Slotted Screen
Sand Pack
Bentonite Seal
Bentonite-Cement
Well Casing VibratingWire
Piezometer(VP)
SignalCable
Organic Soil; Organic Soil with Sand orGravel; Sandy or Gravelly Organic SoilOL/OH
CH Fat Clay; Fat Clay with Sand orGravel; Sandy or Gravelly Fat Clay
Lean Clay; Lean Clay with Sand orGravel; Sandy or Gravelly Lean ClayCL
Clays
Organics
Highly Organic(>50% organic material)
(based on Atterberg Limits)Silty Clay Silty Clay; Silty Clay with Sand or Gravel;Gravelly or Sandy Silty Clay
Sand, Gravel
TraceFewCobbles, BouldersTraceFewLittleSome
Minor Constituents
<55 - 15
<55 - 1015 - 2530 - 45
Moisture
DryMoist
Wet
Absence of moisture, dusty, dry to the touchDamp but no visible water
Visible free water, usually soil is below water table
Cuttings
0511
31
Very looseLooseMedium dense
DenseVery dense
tototo
toto>30
tototo
to>50
41030
50
Very softSoftMedium stiff
StiffVery stiffHard
025
916
148
1530
Well Symbols
Sample Description
Relative Density/Consistency
Soil density/consistency in borings is related primarily to the standardpenetration resistance (N). Soil density/consistency in test pits and probes is
estimated based on visual observation and is presented parenthetically onthe logs.
N(Blows/Foot)SILT or CLAYConsistencySAND or GRAVELRelative Density N(Blows/Foot)
Estimated Percentage
CleanGravels
Gravels
Sands withfew Fines
Sands
Sands withFines
(>12% fines)
1.5" I.D. Split Spoon
Slough
MonumentSurface Seal
Groundwater Indicators
Soil Test Symbols
Sonic Core
Modified CaliforniaSampler
Grab
Sample Symbols
Groundwater Level on Date or At Time of Drilling (ATD)
Groundwater Level on Date Measured in Piezometer
Groundwater Seepage (Test Pits)
Identification of soils in this report is based on visual field and laboratory observations which include density/consistency, moisture condition,grain size, and plasticity estimates and should not be construed to imply field nor laboratory testing unless presented herein. ASTM D 2488visual-manual identification methods were used as a guide. Where laboratory testing confirmed visual-manual identifications, then ASTM D
2487 was used to classify the soils.
Gravels withFines
Elastic Silt; Elastic Silt with Sand orGravel; Sandy or Gravelly Elastic Silt
(5-12% fines)
(>12% fines)
Poorly Graded Gravel with Clay;Poorly Graded Gravel with Clay and Sand
Graph
GW-GM
Symbols
GW
GW-GC
GC
SW
SP
Liquid Limit (LL)Water Content (WC)Plastic Limit (PL)
SW-SM
SW-SC
SP-SM
SP-SC
SM
SC
ML
MH
(<5% fines)
Poorly Graded Sand with Clay;Poorly Graded Sand with Clay and Gravel
TypicalDescriptions
Well-Graded Gravel;Well-Graded Gravel with Sand
Poorly Graded Gravel;Poorly Graded Gravel with Sand
Clayey Gravel;Clayey Gravel with Sand
Well-Graded Sand;Well-Graded Sand with Gravel
Poorly Graded Sand;Poorly Graded Sand with Gravel
Silty Sand;Silty Sand with Gravel
Silty Gravel;Silty Gravel with Sand
PT
CL-ML
Clayey Sand;Clayey Sand with Gravel
Silt; Silt with Sand or Gravel;Sandy or Gravelly Silt
Fine GrainedSoils
More than 50%of MaterialPassing No. 200Sieve
Silts
Well-Graded Gravel with Silt;Well-Graded Gravel with Silt and Sand
Well-Graded Gravel with Clay;Well-Graded Gravel with Clay and Sand
Poorly Graded Gravel with Silt;Poorly Graded Gravel with Silt and Sand
SandandSandySoils
More than50% of CoarseFractionPassing No. 4Sieve
GravelandGravellySoils
More than50% of CoarseFractionRetained onNo. 4 Sieve
CoarseGrainedSoils
More than 50%of MaterialRetained onNo. 200 Sieve
GP
GP-GM
GP-GC
GM
Major Divisions
Well-Graded Sand with SiltWell-Graded Sand with Silt and Gravel
(<5% fines)
Well-Graded Sand with Clay;Well-Graded Sand with Clay and Gravel
Poorly Graded Sand with Silt;Poorly Graded Sand with Silt and Gravel
(5-12% fines)
USCS
USCS Soil Classification Chart (ASTM D 2487)
Extensometer
Sensor (EXT)Extensometer
Anchor
Sheet 1 of 1
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Grass (1.5-inches thick).
Asphalt (2-inches thick).
SILTY SAND (SM), trace gravel, very loose, moist, brown, fine sand,homogeneous.
grades to medium dense, wet
ORGANIC SILT (OL), very soft, wet, dark brown, roots.
SANDY SILT (ML), stiff, moist to wet, light gray, interbedded laminatedfine sand, scattered organics (wood, roots).
Refusal at 13.5 feet.Obstruction encountered at 13.5 ft. The driller was concerned aboutpotential utility and it wasn't able to be identified.
100
274
111
148
S-1GS, WC
S-2
S-3AL
S-4WC
ATD
Sample Data
HA-B1
Boring Log
Logged by:S. Sirmans Drilling Method:Hollow Stem Auger/Mud Rotary
Hammer Type:Auto-hammer
Rig Model/Type:Mobile B-57 / Track-mounted drill rig
Drilling Contractor/Crew:Holt Services, Inc. / A. Causland
10 20 30 40
Hammer Drop Height (inches):30Hammer Weight (pounds):140
WC (%)
Depth to Groundwater:4.5 feet
Checked by:M. Liu
Hole Diameter:6 inches
Comments:
Measured Hammer Efficiency (%): Not Available
Location:Lat: 47.430344 Long: -122.174269 (WGS 84)
Date Completed:02/19/2025
Ground Surface Elevation: 376.89 feet (NAVD 88)
Date Started:02/19/2025
Well Casing Diameter:NA
Total Depth:13.5 feet
General Notes:
1. Refer to Figure A-1 for explanation of descriptions and symbols.
2. Material stratum lines are interpretive and actual changes may be gradual. Solid lines indicate distinct contacts and dashed lines indicate gradual or approximate contacts.
3. USCS designations are based on visual-manual identification (ASTM D 2488), unless otherwise supported by laboratory testing (ASTM D 2487).
4. Groundwater level, if indicated, is at time of drilling/excavation (ATD) or for date specified. Level may vary with time.
5. Location and ground surface elevations are surveyed.
Re
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PL LL
Gr
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Fines Content (%)
Material
Description
Ty
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Number
TestsLe
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(
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SPT N Value
Sheet 1 of 1
Figure A-2Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
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20
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30
35
37
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0
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DR
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Topsoil (5-inches thick).
Residual asphalt/edge of asphalt.
POORLY GRADED SAND WITH GRAVEL (SP), loose, dry to moist,brown, fine to coarse sand, fine gravel, trace organics (roots).
SILTY SAND WITH GRAVEL (SM), very loose, moist, gray,occasional iron oxide staining.
SANDY ORGANIC SOIL (OL), very loose, moist, dark brown, slightorganic odor, organics (wood, roots).
SILT WITH SAND? (ML), stiff, moist, light gray, stratified withapproximately 0.25-inch lenses of poorly graded sand.
SILTY SAND (SM), medium dense, wet, gray-brow, stratified with2-4-inch layers of poorly graded sand.
Vibrating Wire Piezometer #1 installed (S/N VW199258)
SILT WITH SAND (ML), stiff, wet, gray, low plasticity, slow dilatancy,lenses of fine sand, irregular pockets of lean clay at 15.2 and 15.4 ft.
POORLY GRADED GRAVEL WITH SILT (GP-GM), very dense,wet, gray, coarse pulverized gravel, pulverized rock fractured into
thin slices.
SILTY SAND WITH GRAVEL (SM), very dense, moist, light gray,
fine to coarse rounded gravel, nonplastic.
4-inch layers of silty sand at 25.7 ft
grades to strong cementation, homogeneous
grades to wet, gray, fine to coarse sand
becomes homogeneous, poorly graded sand at 35.4 ft
SILTY SAND (SM), very dense, wet, gray, homogeneous.
442
221
249
4911
445
50
4750
50
4350
S-1
S-2a
S-2bWC
S-3GS, WC
S-4WC
S-5AL
S-6
S-7AL, GS, WC
S-8
S-9GS, WC
ATD
Sample Data
HA-B2
Boring Log
Logged by:S. Sirmans Drilling Method:Hollow Stem Auger/Mud Rotary
Hammer Type:Auto-hammer
Rig Model/Type:Mobile B-57 / Track-mounted drill rig
Drilling Contractor/Crew:Holt Services, Inc. / A. Causland
10 20 30 40
Hammer Drop Height (inches):30Hammer Weight (pounds):140
WC (%)
Depth to Groundwater:7.6 feet
Checked by:M. Liu
Hole Diameter:6 inches
Comments:Well Tag ID: BQH800
Measured Hammer Efficiency (%): Not Available
Location:Lat: 47.430342 Long: -122.174606 (WGS 84)
Date Completed:02/17/2025
Ground Surface Elevation: 377.58 feet (NAVD 88)
Date Started:02/17/2025
Well Casing Diameter:ID: 2 inches
Total Depth:61.5 feet
General Notes:
1. Refer to Figure A-1 for explanation of descriptions and symbols.
2. Material stratum lines are interpretive and actual changes may be gradual. Solid lines indicate distinct contacts and dashed lines indicate gradual or approximate contacts.
3. USCS designations are based on visual-manual identification (ASTM D 2488), unless otherwise supported by laboratory testing (ASTM D 2487).
4. Groundwater level, if indicated, is at time of drilling/excavation (ATD) or for date specified. Level may vary with time.
5. Location and ground surface elevations are surveyed.
Re
c
o
v
e
r
y
De
p
t
h
(
f
e
e
t
)
Ele
v
a
t
i
o
n
(
f
e
e
t
)
De
p
t
h
(
f
e
e
t
)
PL LL
Gr
a
p
h
i
c
L
o
g
Fines Content (%)
Material
Description
Ty
p
e
Bl
o
w
C
o
u
n
t
Number
TestsLe
n
g
t
h
(
i
n
c
h
e
s
)
SPT N Value
Sheet 1 of 2
Figure A-3Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
Wa
t
e
r
L
e
v
e
l
HA
B
O
R
I
N
G
L
O
G
-
C
:
\
U
S
E
R
S
\
K
B
U
B
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L
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O
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E
D
R
I
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E
-
H
A
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E
Y
A
L
D
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H
.
C
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\
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S
K
T
O
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\
H
C
_
L
I
B
R
A
R
Y
.
G
L
B
-
4
/
2
2
/
2
5
1
2
:
2
3
-
\
\
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
O
M
\
S
H
A
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E
\
C
F
\
P
R
O
J
E
C
T
S
\
0
2
0
7
9
1
1
\
F
I
E
L
D
D
A
T
A
\
P
E
R
M
_
G
I
N
T
F
I
L
E
S
\
0
2
0
7
9
1
1
-
0
0
1
_
S
O
O
S
C
R
E
E
K
T
R
A
I
L
_
G
I
N
T
.
G
P
J
-
k
b
u
b
e
l
We
l
l
C
o
n
s
t
r
u
c
t
i
o
n
18
18
18
18
18
5
9
5
12
0
5
10
15
20
25
30
35
37
5
37
0
36
5
36
0
35
5
35
0
34
5
34
0
0
5
10
15
20
25
30
35
73
44
32
6
3
13
20
9
50/5"
50/3"
50/5"
50/5.5"
DR
A
F
T
1
1
i
n
.
1
0
i
n
.
1
0
i
n
.
1
8
i
n
.
1
8
i
n
.
SILTY SAND (SM), very dense, wet, gray, homogeneous.(continued)
pockets of silt
SANDY SILT (ML), hard, wet, gray, laminated with 0.25-inch silt, no
to low dilatancy.
Bottom of Borehole at 61.5 feet.
3550
4650
4150
344043
162129
S-10WC
S-11GS, WC
S-12WC
S-13GS, WC
S-14
Sample Data
HA-B2
Boring Log
Logged by:S. Sirmans Drilling Method:Hollow Stem Auger/Mud Rotary
Hammer Type:Auto-hammer
Rig Model/Type:Mobile B-57 / Track-mounted drill rig
Drilling Contractor/Crew:Holt Services, Inc. / A. Causland
10 20 30 40
Hammer Drop Height (inches):30Hammer Weight (pounds):140
WC (%)
Depth to Groundwater:7.6 feet
Checked by:M. Liu
Hole Diameter:6 inches
Comments:Well Tag ID: BQH800
Measured Hammer Efficiency (%): Not Available
Location:Lat: 47.430342 Long: -122.174606 (WGS 84)
Date Completed:02/17/2025
Ground Surface Elevation: 377.58 feet (NAVD 88)
Date Started:02/17/2025
Well Casing Diameter:ID: 2 inches
Total Depth:61.5 feet
General Notes:
1. Refer to Figure A-1 for explanation of descriptions and symbols.
2. Material stratum lines are interpretive and actual changes may be gradual. Solid lines indicate distinct contacts and dashed lines indicate gradual or approximate contacts.
3. USCS designations are based on visual-manual identification (ASTM D 2488), unless otherwise supported by laboratory testing (ASTM D 2487).
4. Groundwater level, if indicated, is at time of drilling/excavation (ATD) or for date specified. Level may vary with time.
5. Location and ground surface elevations are surveyed.
Re
c
o
v
e
r
y
De
p
t
h
(
f
e
e
t
)
Ele
v
a
t
i
o
n
(
f
e
e
t
)
De
p
t
h
(
f
e
e
t
)
PL LL
Gr
a
p
h
i
c
L
o
g
Fines Content (%)
Material
Description
Ty
p
e
Bl
o
w
C
o
u
n
t
Number
TestsLe
n
g
t
h
(
i
n
c
h
e
s
)
SPT N Value
Sheet 2 of 2
Figure A-3Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
Wa
t
e
r
L
e
v
e
l
HA
B
O
R
I
N
G
L
O
G
-
C
:
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S
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S
\
K
B
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B
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\
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E
-
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A
L
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Y
A
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D
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I
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H
.
C
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\
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S
K
T
O
P
\
H
C
_
L
I
B
R
A
R
Y
.
G
L
B
-
4
/
2
2
/
2
5
1
2
:
2
3
-
\
\
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
O
M
\
S
H
A
R
E
\
C
F
\
P
R
O
J
E
C
T
S
\
0
2
0
7
9
1
1
\
F
I
E
L
D
D
A
T
A
\
P
E
R
M
_
G
I
N
T
F
I
L
E
S
\
0
2
0
7
9
1
1
-
0
0
1
_
S
O
O
S
C
R
E
E
K
T
R
A
I
L
_
G
I
N
T
.
G
P
J
-
k
b
u
b
e
l
We
l
l
C
o
n
s
t
r
u
c
t
i
o
n
11
12
12
18
18
40
45
50
55
60
65
70
75
33
5
33
0
32
5
32
0
31
5
31
0
30
5
30
0
40
45
50
55
60
65
70
75
46
91
50/5"
50/5.5"
50/5.5"
83
50
DR
A
F
T
1
0
i
n
.
1
6
i
n
.
1
8
i
n
.
8
i
n
.
1
2
i
n
.
8
i
n
.
6
i
n
.
5
i
n
.
Topsoil (grass, roots) (6-inches thick).
POORLY GRADED SAND WITH GRAVEL (SP), loose, dry, brown, finesand, rounded gravel.
SILTY SAND (SM), loose, dry to moist, gray-brown, fine to coarse gravel,
iron oxide staining, trace organics (roots), laminated rocks.
SANDY ORGANIC SOIL WITH GRAVEL (OL), very loose, moist, darkbrown, fine rounded gravel, scattered organics (roots).
SILTY SAND (SM), very loose, dry to moist, gray-brown.
POORLY GRADED SAND WITH SILT (SP-SM), trace fine gravel,medium dense, moist, gray, fine to coarse sand.
ELASTIC SILT (ML), medium stiff, moist, gray to yellow-brown.
SILTY SAND (SM), trace fine gravel, medium dense, wet, gray, fine tocoarse sand, homogeneous.
grades to gray to red-brown, 3.5-inch layer of iron oxide staining2-inch layer of sandy silt at 15.8 ft
SILT (ML), trace gravel, medium stiff, wet, gray, 0.5-inch seam of clayedsand with low plasticity.
SILTY SAND WITH GRAVEL (SM), very dense, wet, gray, fine to coarsegravel, scattered poorly graded sand.
decrease in gravel
POORLY GRADED GRAVEL (GP), very dense, wet, gray-brown,
subangular gravel, low recovery, fractured rock only.
463
101
256
357
11109
3510
50
50
S-1WC
S-2aWCS-2b
S-3aS-3b
S-4GS, WC
S-5
S-6AL, WC
S-7
S-8GS, WC
ATD
Sample Data
HA-B3
Boring and VWP Log
Logged by:S. Sirmans Drilling Method:Hollow Stem Auger/Mud Rotary
Hammer Type:Auto-hammer
Rig Model/Type:Mobile B-57 / Track-mounted drill rig
Drilling Contractor/Crew:Holt Services, Inc. / A. Causland
10 20 30 40
Hammer Drop Height (inches):30Hammer Weight (pounds):140
WC (%)
Depth to Groundwater:7.2 feet
Checked by:M. Liu
Hole Diameter:6 inches
Comments:
Measured Hammer Efficiency (%): Not Available
Location:Lat: 47.430355 Long: -122.174897 (WGS 84)
Date Completed:02/18/2025
Ground Surface Elevation: 377.62 feet (NAVD 88)
Date Started:02/18/2025
Well Casing Diameter:NA
Total Depth:61.5 feet
General Notes:
1. Refer to Figure A-1 for explanation of descriptions and symbols.
2. Material stratum lines are interpretive and actual changes may be gradual. Solid lines indicate distinct contacts and dashed lines indicate gradual or approximate contacts.
3. USCS designations are based on visual-manual identification (ASTM D 2488), unless otherwise supported by laboratory testing (ASTM D 2487).
4. Groundwater level, if indicated, is at time of drilling/excavation (ATD) or for date specified. Level may vary with time.
5. Location and ground surface elevations are surveyed.
Re
c
o
v
e
r
y
De
p
t
h
(
f
e
e
t
)
Ele
v
a
t
i
o
n
(
f
e
e
t
)
De
p
t
h
(
f
e
e
t
)
PL LL
Gr
a
p
h
i
c
L
o
g
Fines Content (%)
Material
Description
Ty
p
e
Bl
o
w
C
o
u
n
t
Number
TestsLe
n
g
t
h
(
i
n
c
h
e
s
)
SPT N Value
Sheet 1 of 2
Figure A-4Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
Wa
t
e
r
L
e
v
e
l
HA
B
O
R
I
N
G
L
O
G
-
\
\
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
O
M
\
S
H
A
R
E
\
S
E
A
_
D
A
T
A
\
G
I
N
T
\
H
C
_
L
I
B
R
A
R
Y
.
G
L
B
-
3
/
1
7
/
2
5
1
2
:
2
8
-
\
\
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
O
M
\
S
H
A
R
E
\
C
F
\
P
R
O
J
E
C
T
S
\
0
2
0
7
9
1
1
\
F
I
E
L
D
D
A
T
A
\
P
E
R
M
_
G
I
N
T
F
I
L
E
S
\
0
2
0
7
9
1
1
-
0
0
1
_
S
O
O
S
C
R
E
E
K
T
R
A
I
L
_
G
I
N
T
.
G
P
J
-
k
b
u
b
e
l
18
18
18
18
18
18
6
5
0
5
10
15
20
25
30
35
37
5
37
0
36
5
36
0
35
5
35
0
34
5
34
0
0
5
10
15
20
25
30
35
85.3
14
22
9
1
11
12
19
15
50/6"
50/4.5"DR
A
F
T
2
i
n
.
1
1
i
n
.
1
8
i
n
.
POORLY GRADED GRAVEL (GP), very dense, wet, gray-brown,subangular gravel, low recovery, fractured rock only. (continued)
ELASTIC SILT (ML), hard, wet, gray, few fine sand.
grades to moist, increased sand content
0.5-inch seam of fine sand with 0.25-inch seam of silt at 61 ft
Bottom of Borehole at 61.5 feet.
50
3950
353950
S-9
S-10WC
S-11AL, GS, WC
Sample Data
HA-B3
Boring and VWP Log
Logged by:S. Sirmans Drilling Method:Hollow Stem Auger/Mud Rotary
Hammer Type:Auto-hammer
Rig Model/Type:Mobile B-57 / Track-mounted drill rig
Drilling Contractor/Crew:Holt Services, Inc. / A. Causland
10 20 30 40
Hammer Drop Height (inches):30Hammer Weight (pounds):140
WC (%)
Depth to Groundwater:7.2 feet
Checked by:M. Liu
Hole Diameter:6 inches
Comments:
Measured Hammer Efficiency (%): Not Available
Location:Lat: 47.430355 Long: -122.174897 (WGS 84)
Date Completed:02/18/2025
Ground Surface Elevation: 377.62 feet (NAVD 88)
Date Started:02/18/2025
Well Casing Diameter:NA
Total Depth:61.5 feet
General Notes:
1. Refer to Figure A-1 for explanation of descriptions and symbols.
2. Material stratum lines are interpretive and actual changes may be gradual. Solid lines indicate distinct contacts and dashed lines indicate gradual or approximate contacts.
3. USCS designations are based on visual-manual identification (ASTM D 2488), unless otherwise supported by laboratory testing (ASTM D 2487).
4. Groundwater level, if indicated, is at time of drilling/excavation (ATD) or for date specified. Level may vary with time.
5. Location and ground surface elevations are surveyed.
Re
c
o
v
e
r
y
De
p
t
h
(
f
e
e
t
)
Ele
v
a
t
i
o
n
(
f
e
e
t
)
De
p
t
h
(
f
e
e
t
)
PL LL
Gr
a
p
h
i
c
L
o
g
Fines Content (%)
Material
Description
Ty
p
e
Bl
o
w
C
o
u
n
t
Number
TestsLe
n
g
t
h
(
i
n
c
h
e
s
)
SPT N Value
Sheet 2 of 2
Figure A-4Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
Wa
t
e
r
L
e
v
e
l
HA
B
O
R
I
N
G
L
O
G
-
\
\
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
O
M
\
S
H
A
R
E
\
S
E
A
_
D
A
T
A
\
G
I
N
T
\
H
C
_
L
I
B
R
A
R
Y
.
G
L
B
-
3
/
1
7
/
2
5
1
2
:
2
8
-
\
\
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
O
M
\
S
H
A
R
E
\
C
F
\
P
R
O
J
E
C
T
S
\
0
2
0
7
9
1
1
\
F
I
E
L
D
D
A
T
A
\
P
E
R
M
_
G
I
N
T
F
I
L
E
S
\
0
2
0
7
9
1
1
-
0
0
1
_
S
O
O
S
C
R
E
E
K
T
R
A
I
L
_
G
I
N
T
.
G
P
J
-
k
b
u
b
e
l
2
12
18
40
45
50
55
60
65
70
75
33
5
33
0
32
5
32
0
31
5
31
0
30
5
30
0
40
45
50
55
60
65
70
75
88
50/2"
50/6"
89
DR
A
F
T
2
i
n
.
1
4
i
n
.
1
6
i
n
.
1
1
i
n
.
8
i
n
.
1
2
i
n
.
1
2
i
n
.
8
i
n
.
Topsoil (4-inches thick).
SILTY SAND (SM), very loose, moist, brown, occasional organics (roots),low recovery.
grades to trace fine gravel, dark brown, strateified dark brown to brown
POORLY GRADED SAND (SP), medium dense, wet, gray,homogeneous.
SILTY SAND (SM), trace fine gravel, medium dense, wet, brown, fine tocoarse sand.
grades to dense
SILT WITH SAND (ML), trace fine gravel, hard, wet, brown, fine sand,moderate to strong cementation.
Bottom of Borehole at 30.8 feet.
222
202
61012
12129
151315
162019
2750
4450
S-1
S-2GS, WC
S-3
S-4WC
S-5GS, WC
S-6
S-7AL
S-8
ATD
Sample Data
HA-B4
Boring Log
Logged by:S. Sirmans Drilling Method:Hollow Stem Auger/Mud Rotary
Hammer Type:Auto-hammer
Rig Model/Type:Mobile B-57 / Track-mounted drill rig
Drilling Contractor/Crew:Holt Services, Inc. / A. Causland
10 20 30 40
Hammer Drop Height (inches):30Hammer Weight (pounds):140
WC (%)
Depth to Groundwater:6.167 feet
Checked by:M. Liu
Hole Diameter:6 inches
Comments:
Measured Hammer Efficiency (%): Not Available
Location:Lat: 47.430370 Long: -122.175227 (WGS 84)
Date Completed:02/19/2025
Ground Surface Elevation: 379.92 feet (NAVD 88)
Date Started:02/19/2025
Well Casing Diameter:NA
Total Depth:30.8 feet
General Notes:
1. Refer to Figure A-1 for explanation of descriptions and symbols.
2. Material stratum lines are interpretive and actual changes may be gradual. Solid lines indicate distinct contacts and dashed lines indicate gradual or approximate contacts.
3. USCS designations are based on visual-manual identification (ASTM D 2488), unless otherwise supported by laboratory testing (ASTM D 2487).
4. Groundwater level, if indicated, is at time of drilling/excavation (ATD) or for date specified. Level may vary with time.
5. Location and ground surface elevations are surveyed.
Re
c
o
v
e
r
y
De
p
t
h
(
f
e
e
t
)
Ele
v
a
t
i
o
n
(
f
e
e
t
)
De
p
t
h
(
f
e
e
t
)
PL LL
Gr
a
p
h
i
c
L
o
g
Fines Content (%)
Material
Description
Ty
p
e
Bl
o
w
C
o
u
n
t
Number
TestsLe
n
g
t
h
(
i
n
c
h
e
s
)
SPT N Value
Sheet 1 of 1
Figure A-5Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
Wa
t
e
r
L
e
v
e
l
HA
B
O
R
I
N
G
L
O
G
-
\
\
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
O
M
\
S
H
A
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E
\
S
E
A
_
D
A
T
A
\
G
I
N
T
\
H
C
_
L
I
B
R
A
R
Y
.
G
L
B
-
3
/
1
7
/
2
5
1
2
:
2
8
-
\
\
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
O
M
\
S
H
A
R
E
\
C
F
\
P
R
O
J
E
C
T
S
\
0
2
0
7
9
1
1
\
F
I
E
L
D
D
A
T
A
\
P
E
R
M
_
G
I
N
T
F
I
L
E
S
\
0
2
0
7
9
1
1
-
0
0
1
_
S
O
O
S
C
R
E
E
K
T
R
A
I
L
_
G
I
N
T
.
G
P
J
-
k
b
u
b
e
l
18
18
18
18
18
18
12
9
0
5
10
15
20
25
30
35
37
5
37
0
36
5
36
0
35
5
35
0
34
5
0
5
10
15
20
25
30
35
70.3
42
19
4
2
22
21
28
39
50/5.5"
50/3"DR
A
F
T
1
0
i
n
.
1
6
i
n
.
1
8
i
n
.
1
5
i
n
.
1
1
i
n
.
1
3
i
n
.
5
i
n
.
Topsoil (12-inches thick), silty sand with organics (grass), few fine gravel.
POORLY GRADED SAND WITH SILT (SP-SM), trace stratified finegravel, very loose, moist, gray to brown, fine to coarse sand, traceorganics (roots).
SILTY SAND (SM), trace fine gravel, medium dense, moist, gray, finesand, homogeneous.
grades to trace fine to coarse gravel, wet, light-brown, iron oxide staining
POORLY GRADED SAND WITH SILT AND GRAVEL (SP-SM), mediumdense, wet, gray to gray-brown, fine to coarse sand, fine to coarse gravel,
occasional iron oxide staining.
POORLY GRADED SAND WITH SILT (SP-SM), medium dense, wet,gray-brown, fine to coarse sand, laminated, occasional iron oxidestaining.
SILT WITH SAND (ML), hard, moist, gray, fine sand, strong cementation,homogeneous.
Bottom of Borehole at 30.5 feet.
004
989
2713
8812
151311
121112
151114
50
S-1
S-2GS, WC
S-3
S-4WC
S-5GS, WC
S-6WC
S-7
S-8AL
ATD
Sample Data
HA-B5
Boring Log
Logged by:S. Sirmans Drilling Method:Hollow Stem Auger/Mud Rotary
Hammer Type:Auto-hammer
Rig Model/Type:Mobile B-57 / Track-mounted drill rig
Drilling Contractor/Crew:Holt Services, Inc. / A. Causland
10 20 30 40
Hammer Drop Height (inches):30Hammer Weight (pounds):140
WC (%)
Depth to Groundwater:9 feet
Checked by:M. Liu
Hole Diameter:6 inches
Comments:
Measured Hammer Efficiency (%): Not Available
Location:Lat: 47.430988 Long: -122.175726 (WGS 84)
Date Completed:02/20/2025
Ground Surface Elevation: 386.16 feet (NAVD 88)
Date Started:02/20/2025
Well Casing Diameter:NA
Total Depth:30.5 feet
General Notes:
1. Refer to Figure A-1 for explanation of descriptions and symbols.
2. Material stratum lines are interpretive and actual changes may be gradual. Solid lines indicate distinct contacts and dashed lines indicate gradual or approximate contacts.
3. USCS designations are based on visual-manual identification (ASTM D 2488), unless otherwise supported by laboratory testing (ASTM D 2487).
4. Groundwater level, if indicated, is at time of drilling/excavation (ATD) or for date specified. Level may vary with time.
5. Location and ground surface elevations are surveyed.
Re
c
o
v
e
r
y
De
p
t
h
(
f
e
e
t
)
Ele
v
a
t
i
o
n
(
f
e
e
t
)
De
p
t
h
(
f
e
e
t
)
PL LL
Gr
a
p
h
i
c
L
o
g
Fines Content (%)
Material
Description
Ty
p
e
Bl
o
w
C
o
u
n
t
Number
TestsLe
n
g
t
h
(
i
n
c
h
e
s
)
SPT N Value
Sheet 1 of 1
Figure A-6Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
Wa
t
e
r
L
e
v
e
l
HA
B
O
R
I
N
G
L
O
G
-
\
\
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
O
M
\
S
H
A
R
E
\
S
E
A
_
D
A
T
A
\
G
I
N
T
\
H
C
_
L
I
B
R
A
R
Y
.
G
L
B
-
3
/
1
7
/
2
5
1
2
:
2
8
-
\
\
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
O
M
\
S
H
A
R
E
\
C
F
\
P
R
O
J
E
C
T
S
\
0
2
0
7
9
1
1
\
F
I
E
L
D
D
A
T
A
\
P
E
R
M
_
G
I
N
T
F
I
L
E
S
\
0
2
0
7
9
1
1
-
0
0
1
_
S
O
O
S
C
R
E
E
K
T
R
A
I
L
_
G
I
N
T
.
G
P
J
-
k
b
u
b
e
l
18
18
18
18
18
18
18
5
0
5
10
15
20
25
30
35
38
5
38
0
37
5
37
0
36
5
36
0
35
5
35
0
0
5
10
15
20
25
30
35
37
9
4
17
20
20
24
23
25
50/5"DR
A
F
T
Topsoil (grass) (3-inches thick).
SILTY SAND (SM), some fine to coarse gravel, trace cobbles, (loose to mediumdense), dry to moist, brown, fine to coarse sand.
LEAN CLAY (CL), (medium stiff to stiff), dry, gray.
SILTY SAND WITH GRAVEL (SM), some cobbles, (dense), moist, red-brown to
brown, fine to coarse sand.
POORLY GRADED SAND (SP), some cobbles, (dense), moist, yellow-brown,
coarse sand.
Bottom of Test Pit at 12.0 feet.
S-1
G-1GS, WC
G-2WC
G-3
G-4WC
G-5
Sample Data
Test Pit Log
HA-TP1
WC
10 20 30 40
General Notes:
1. Refer to Figure A-1 for explanation of descriptions and symbols.
2. Material stratum lines are interpretive and actual changes may be gradual. Solid lines indicate distinct contacts and dashed lines indicate gradual or approximate contacts.
3. USCS designations are based on visual-manual identification (ASTM D 2488), unless otherwise supported by laboratory testing (ASTM D 2487).
4. Groundwater level, if indicated, is at time of drilling/excavation (ATD) or for date specified. Level may vary with time.
5. Location and ground surface elevations are surveyed.
De
p
t
h
(
f
e
e
t
)
Ele
v
a
t
i
o
n
(
f
e
e
t
)
De
p
t
h
(
f
e
e
t
)
Gr
a
p
h
i
c
L
o
g
Fines Content (%)
Material
Description
Ty
p
e
Number
TestsLe
n
g
t
h
(
i
n
c
h
e
s
)
Contractor/Crew:Holocene Drilling, Inc. / P. Curnett
Rig Model/Type:Hitachi 75 / Excavator
Comments:
Depth to Seepage:Not Encountered
Logged by:A. Ung Checked by:M. Liu
Location:Lat: 47.430512 Long: -122.175667 (WGS 84)
Ground Surface Elevation: 389.70 feet (NAVD 88)
Date Started:01/31/2025 Date Completed:01/31/2025
Total Depth:12.0 feet
Sheet 1 of 1
Figure A-7Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
HA
T
E
S
T
P
I
T
-
\
\
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
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\
S
H
A
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\
S
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D
A
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A
\
G
I
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T
\
H
C
_
L
I
B
R
A
R
Y
.
G
L
B
-
3
/
1
7
/
2
5
1
2
:
2
8
-
\
\
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A
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Y
A
L
D
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I
C
H
.
C
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M
\
S
H
A
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E
\
C
F
\
P
R
O
J
E
C
T
S
\
0
2
0
7
9
1
1
\
F
I
E
L
D
D
A
T
A
\
P
E
R
M
_
G
I
N
T
F
I
L
E
S
\
0
2
0
7
9
1
1
-
0
0
1
_
S
O
O
S
C
R
E
E
K
T
R
A
I
L
_
G
I
N
T
.
G
P
J
-
k
b
u
b
e
l
0.0
2.5
5.0
7.5
10.0
12.5
38
7
.
5
38
5
.
0
38
2
.
5
38
0
.
0
37
7
.
5
37
5
.
0
0.0
2.5
5.0
7.5
10.0
12.5
35
DR
A
F
T
Topsoil (grass) (3-inches thick).
SILTY SAND WITH GRAVEL (SM), trace cobbles, (loose to medium dense), dry tomoist, brown, fine to coarse sand.
LEAN CLAY (CL), (stiff), dry, gray.
CLAYEY SAND WITH GRAVEL (SC), some cobbles, (dense), moist, gray, fine
sand.
Bottom of Test Pit at 12.5 feet.
G-1WC
G-2
G-3GS, WC
Sample Data
Test Pit Log
HA-TP2
WC
10 20 30 40
General Notes:
1. Refer to Figure A-1 for explanation of descriptions and symbols.
2. Material stratum lines are interpretive and actual changes may be gradual. Solid lines indicate distinct contacts and dashed lines indicate gradual or approximate contacts.
3. USCS designations are based on visual-manual identification (ASTM D 2488), unless otherwise supported by laboratory testing (ASTM D 2487).
4. Groundwater level, if indicated, is at time of drilling/excavation (ATD) or for date specified. Level may vary with time.
5. Location and ground surface elevations are surveyed.
De
p
t
h
(
f
e
e
t
)
Ele
v
a
t
i
o
n
(
f
e
e
t
)
De
p
t
h
(
f
e
e
t
)
Gr
a
p
h
i
c
L
o
g
Fines Content (%)
Material
Description
Ty
p
e
Number
TestsLe
n
g
t
h
(
i
n
c
h
e
s
)
Contractor/Crew:Holocene Drilling, Inc. / P. Curnett
Rig Model/Type:Hitachi 75 / Excavator
Comments:
Depth to Seepage:Not Encountered
Logged by:A. Ung Checked by:M. Liu
Location:Lat: 47.430709 Long: -122.175689 (WGS 84)
Ground Surface Elevation: 388.37 feet (NAVD 88)
Date Started:01/31/2025 Date Completed:01/31/2025
Total Depth:12.5 feet
Sheet 1 of 1
Figure A-8Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
HA
T
E
S
T
P
I
T
-
\
\
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
O
M
\
S
H
A
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E
\
S
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A
_
D
A
T
A
\
G
I
N
T
\
H
C
_
L
I
B
R
A
R
Y
.
G
L
B
-
3
/
1
7
/
2
5
1
2
:
2
8
-
\
\
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
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\
S
H
A
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E
\
C
F
\
P
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J
E
C
T
S
\
0
2
0
7
9
1
1
\
F
I
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L
D
D
A
T
A
\
P
E
R
M
_
G
I
N
T
F
I
L
E
S
\
0
2
0
7
9
1
1
-
0
0
1
_
S
O
O
S
C
R
E
E
K
T
R
A
I
L
_
G
I
N
T
.
G
P
J
-
k
b
u
b
e
l
0.0
2.5
5.0
7.5
10.0
12.5
38
7
.
5
38
5
.
0
38
2
.
5
38
0
.
0
37
7
.
5
37
5
.
0
0.0
2.5
5.0
7.5
10.0
12.5
45DR
A
F
T
Topsoil (grass) (5-inches thick).
SILTY SAND WITH GRAVEL (SM), (loose), dry to moist, brown.
sand and gravel content increases with depth
SILTY SAND (SM), (medium dense), dry to moist, gray, fine sand.
CLAYEY SAND WITH GRAVEL (SC), some cobbles, (medium dense to dense),
moist to wet, gray-brown, coarse sand.
Bottom of Test Pit at 10.0 feet.
G-1
G-2GS, WC
G-3WC 1
/
3
1
/
2
0
2
5
Sample Data
Test Pit Log
HA-TP3
WC
10 20 30 40
General Notes:
1. Refer to Figure A-1 for explanation of descriptions and symbols.
2. Material stratum lines are interpretive and actual changes may be gradual. Solid lines indicate distinct contacts and dashed lines indicate gradual or approximate contacts.
3. USCS designations are based on visual-manual identification (ASTM D 2488), unless otherwise supported by laboratory testing (ASTM D 2487).
4. Groundwater level, if indicated, is at time of drilling/excavation (ATD) or for date specified. Level may vary with time.
5. Location and ground surface elevations are surveyed.
De
p
t
h
(
f
e
e
t
)
Ele
v
a
t
i
o
n
(
f
e
e
t
)
De
p
t
h
(
f
e
e
t
)
Gr
a
p
h
i
c
L
o
g
Fines Content (%)
Material
Description
Ty
p
e
Number
TestsLe
n
g
t
h
(
i
n
c
h
e
s
)
Contractor/Crew:Holocene Drilling, Inc. / P. Curnett
Rig Model/Type:Hitachi 75 / Excavator
Comments:
Depth to Seepage:10 feet
Logged by:A. Ung Checked by:M. Liu
Location:Lat: 47.431203 Long: -122.175701 (WGS 84)
Ground Surface Elevation: 385.93 feet (NAVD 88)
Date Started:01/31/2025 Date Completed:01/31/2025
Total Depth:10.0 feet
Sheet 1 of 1
Figure A-9Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
Wa
t
e
r
L
e
v
e
l
HA
T
E
S
T
P
I
T
-
\
\
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
O
M
\
S
H
A
R
E
\
S
E
A
_
D
A
T
A
\
G
I
N
T
\
H
C
_
L
I
B
R
A
R
Y
.
G
L
B
-
3
/
1
7
/
2
5
1
2
:
2
8
-
\
\
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
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M
\
S
H
A
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E
\
C
F
\
P
R
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J
E
C
T
S
\
0
2
0
7
9
1
1
\
F
I
E
L
D
D
A
T
A
\
P
E
R
M
_
G
I
N
T
F
I
L
E
S
\
0
2
0
7
9
1
1
-
0
0
1
_
S
O
O
S
C
R
E
E
K
T
R
A
I
L
_
G
I
N
T
.
G
P
J
-
k
b
u
b
e
l
0.0
2.5
5.0
7.5
10.0
12.5
38
5
.
0
38
2
.
5
38
0
.
0
37
7
.
5
37
5
.
0
37
2
.
5
0.0
2.5
5.0
7.5
10.0
12.5
43
DR
A
F
T
Topsoil (grass) (5-inches thick).
SILTY SAND WITH GRAVEL (SM), (loose), dry to moist, brown.
LEAN CLAY (CL), (stiff), dry to moist, gray, blocky structure.
SANDY LEAN CLAY WITH GRAVEL (CL), (dense), dry to moist, gray, increased
sand, gravel and cobbles with depth.
Bottom of Test Pit at 10.0 feet.
G-1AL, GS, WC
G-2
G-3WC
Sample Data
Test Pit Log
HA-TP4
WC
10 20 30 40
General Notes:
1. Refer to Figure A-1 for explanation of descriptions and symbols.
2. Material stratum lines are interpretive and actual changes may be gradual. Solid lines indicate distinct contacts and dashed lines indicate gradual or approximate contacts.
3. USCS designations are based on visual-manual identification (ASTM D 2488), unless otherwise supported by laboratory testing (ASTM D 2487).
4. Groundwater level, if indicated, is at time of drilling/excavation (ATD) or for date specified. Level may vary with time.
5. Location and ground surface elevations are surveyed.
De
p
t
h
(
f
e
e
t
)
Ele
v
a
t
i
o
n
(
f
e
e
t
)
De
p
t
h
(
f
e
e
t
)
PL LL
Gr
a
p
h
i
c
L
o
g
Fines Content (%)
Material
Description
Ty
p
e
Number
TestsLe
n
g
t
h
(
i
n
c
h
e
s
)
Contractor/Crew:Holocene Drilling, Inc. / P. Curnett
Rig Model/Type:Hitachi 75 / Excavator
Comments:
Depth to Seepage:Not Encountered
Logged by:A. Ung Checked by:M. Liu
Location:Lat: 47.431382 Long: -122.175695 (WGS 84)
Ground Surface Elevation: 387.24 feet (NAVD 88)
Date Started:01/31/2025 Date Completed:01/31/2025
Total Depth:10.0 feet
Sheet 1 of 1
Figure A-10Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
HA
T
E
S
T
P
I
T
-
\
\
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
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M
\
S
H
A
R
E
\
S
E
A
_
D
A
T
A
\
G
I
N
T
\
H
C
_
L
I
B
R
A
R
Y
.
G
L
B
-
3
/
1
7
/
2
5
1
2
:
2
8
-
\
\
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A
L
E
Y
A
L
D
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I
C
H
.
C
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\
S
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\
C
F
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C
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S
\
0
2
0
7
9
1
1
\
F
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D
D
A
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A
\
P
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_
G
I
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T
F
I
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S
\
0
2
0
7
9
1
1
-
0
0
1
_
S
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S
C
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E
K
T
R
A
I
L
_
G
I
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T
.
G
P
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-
k
b
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b
e
l
0.0
2.5
5.0
7.5
10.0
12.5
38
5
.
0
38
2
.
5
38
0
.
0
37
7
.
5
37
5
.
0
37
2
.
5
0.0
2.5
5.0
7.5
10.0
12.5
93
DR
A
F
T
Topsoil with roots, organics (3-inches thick).
SILTY SAND WITH GRAVEL (SM), trace cobbles, (loose to medium dense), dry tomoist, brown to dark brown, fine to coarse sand and gravel, occasional roots.
POORLY GRADED SAND WITH SILT AND GRAVEL (SP-SM), some cobles,(medium dense), moist, gray-brown, fine to coarse sand and gravel.
SILTY SAND (SM), some cobbles, (dense), moist, gray-brown.
Bottom of Test Pit at 12.0 feet.
G-1
G-2GS, WC
G-3WC
Sample Data
Test Pit Log
HA-TP5
WC
10 20 30 40
General Notes:
1. Refer to Figure A-1 for explanation of descriptions and symbols.
2. Material stratum lines are interpretive and actual changes may be gradual. Solid lines indicate distinct contacts and dashed lines indicate gradual or approximate contacts.
3. USCS designations are based on visual-manual identification (ASTM D 2488), unless otherwise supported by laboratory testing (ASTM D 2487).
4. Groundwater level, if indicated, is at time of drilling/excavation (ATD) or for date specified. Level may vary with time.
5. Location and ground surface elevations are surveyed.
De
p
t
h
(
f
e
e
t
)
Ele
v
a
t
i
o
n
(
f
e
e
t
)
De
p
t
h
(
f
e
e
t
)
Gr
a
p
h
i
c
L
o
g
Fines Content (%)
Material
Description
Ty
p
e
Number
TestsLe
n
g
t
h
(
i
n
c
h
e
s
)
Contractor/Crew:Holocene Drilling, Inc. / P. Curnett
Rig Model/Type:Hitachi 75 / Excavator
Comments:
Depth to Seepage:Not Encountered
Logged by:A. Ung Checked by:M. Liu
Location:Lat: 47.431659 Long: -122.175819 (WGS 84)
Ground Surface Elevation: 389.69 feet (NAVD 88)
Date Started:01/31/2025 Date Completed:01/31/2025
Total Depth:12.0 feet
Sheet 1 of 1
Figure A-11Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
HA
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0.0
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7.5
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12.5
38
7
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38
5
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38
2
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5
38
0
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37
7
.
5
37
5
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0
0.0
2.5
5.0
7.5
10.0
12.5
9
DR
A
F
T
APPENDIX B
Laboratory Testing Program
DR
A
F
T
APPENDIX B
Laboratory Testing Program
A laboratory testing program was performed for this study to evaluate the basic index and geotechnical
engineering properties of the site soils. Disturbed soil samples were tested. The tests performed and the
procedures followed are outlined below.
SOIL CLASSIFICATION
Soil samples from the explorations were visually classified in the field and then taken to our laboratory
where the classifications were verified in a relatively controlled laboratory environment. Field and
laboratory observations include density/consistency, moisture condition, and grain size and plasticity
estimates.
The classifications of selected samples were checked by laboratory tests such as Atterberg limits
determinations and grain size analysis. Classifications were made in general accordance with the
Visual-Manual Procedure, ASTM International (ASTM) D 2488. Lab test results are summarized on
Figure B-1.
WATER CONTENT DETERMINATIONS
Water contents were determined, for most samples recovered in the explorations, in general
accordance with ASTM D 2216, as soon as possible following their arrival in our laboratory. Water
contents were not determined for very small samples nor samples where large gravel contents would
result in values considered unrepresentative. The results of water content tests are plotted at their
respective sample depths on the exploration logs.
ATTERBERG LIMITS
We determined Atterberg Limits (AL) for fine-grained soil samples. The liquid limit and plastic limit were
determined in general accordance with ASTM D 4318. The results of the ALs analysis and plasticity
characteristics are shown graphically on the boring logs and plotted on Figure B-2. This relates the
plasticity index (liquid limit minus the plastic limit) to the liquid limit.
GRAIN SIZE ANALYSIS
Grain size (GS) distribution was analyzed on representative samples in general accordance with
ASTM D 422. Wet sieve analysis was used to determine the size distribution greater than U.S. No. 200
mesh sieve. The results of the tests are presented as curves plotting percent finer by weight versus grain
size on Figure B-3.
ORGANIC CONTENT
The organic content of selected soil samples were determined in accordance with guidelines presented
in American Society for Testing and Materials (ASTM) D 2974. The moisture content of the samples were
determined by drying the samples in a standard drying oven and expressed as a percentage of the
sample weight. The organic content is determined by igniting the oven-dried sample in a muffle furnace.
DR
A
F
T
The resulting substance is ash, which is expressed as a percentage of the oven-dried sample. The organic
content is included in the logs presented in this appendix.
CORROSION TESTS
We submitted one composite soil sample from HA-B2 to HWA for corrosion tests. Tests on pH,
resistivity, chloride and sulfate were conducted, and results are presented in this appendix.
DR
A
F
T
HA-B1 S-1 2.5 17 28 52 20
HA-B1 S-3 7.5 168 123 45 18.3
HA-B1 S-4 10.0 24 1.5
HA-B2 S-2b 6.2 49 10.8
HA-B2 S-3 7.5 22 73 25 2
HA-B2 S-4 10.0 19
HA-B2 S-5 15.0 18 17 1
HA-B2 S-7 25.0 13 44 41 16 14 14 NP
HA-B2 S-9 35.0 17 32 52 16
HA-B2 S-10 40.0 21
HA-B2 S-11 45.0 21 46 54 1
HA-B2 S-12 50.0 20
HA-B2 S-13 55.0 24 91 9 0
HA-B3 S-1 2.5 21
HA-B3 S-2a 5.0 85 34 33 1 14.3
HA-B3 S-4 10.0 17 14 75 11
HA-B3 S-6 20.0 30 19 17 2
HA-B3 S-8 30.0 15 22 60 18
HA-B3 S-10 50.0 25
HA-B3 S-11 60.0 26 88 12 0 21 21 NP
HA-B4 S-2 5.0 70 42 53 5
HA-B4 S-4 10.0 16
HA-B4 S-5 15.0 14 19 64 18
HA-B4 S-7 25.0 16 14 2
HA-B5 S-2 5.0 10 37 60 4
HA-B5 S-4 10.0 21
HA-B5 S-5 15.0 15 9 62 30
HA-B5 S-6 20.0 18
HA-B5 S-8 30.0 15 15 NP
HA-TP1 G-1 3.0 14 35 53 12
HA-TP1 G-2 5.0 12
HA-TP1 G-4 8.0 12
HA-TP2 G-1 4.0 12
HA-TP2 G-3 12.0 14 45 52 3
HA-TP3 G-2 7.0 13 43 50 7
HA-TP3 G-3 9.5 12
HA-TP4 G-1 3.0 23 93 7 0 42 18 24
HA-TP4 G-3 9.5 13
HA-TP5 G-2 7.0 5 9 52 39
HA-TP5 G-3 11.5 18
Sheet 1 of 1
Figure B-1Summary of
Laboratory Results
DryDensity(pcf)
Fines
(%)
Sand
(%)
Liquid
Limit
WaterContent(%)
Plastic
Limit
Plasticity
Index
PocketPen(tsf)
Torvane
(tsf)
OrganicContent(%)
Exploration Sample
ID Depth Gravel
(%)
Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
HA
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a
h
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t
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DR
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50
Dashed line indicates the approximate
upper limit boundary for natural soils
10
LIQUID LIMIT
PL
A
S
T
I
C
I
T
Y
I
N
D
E
X
Remarks:
USCSLL PL PILocation and Description
123
17
14
33
45
1
NP
1
NT
NT
44
NT
Depth: 7.5 to 9.0
Depth: 15.0 to 16.5
Depth: 25.0 to 25.8
Depth: 5.0 to 6.0
MC%-#200
40
30
20
10
Liquid Limit,
Plastic Limit, and
Plasticity Index
ELASTIC SILT
SILT
SILTY SAND WITH GRAVEL
SILT
50
30
7
4
70 90
NT
NT
13
85
MH
ML
SM
ML
Sample No.: S-3
Sample No.: S-5
Sample No.: S-7
Sample No.: S-2a
110
60
Source: HA-B1
Source: HA-B2
Source: HA-B2
Source: HA-B3
168
18
14
34
Sheet 1 of 3
Figure B-2Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
HA
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CL-ML
CH o
r
O
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ML or OL MH or OH
CL o
r
O
L
CL-ML
DR
A
F
T
50
Dashed line indicates the approximate
upper limit boundary for natural soils
10
LIQUID LIMIT
PL
A
S
T
I
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I
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Y
I
N
D
E
X
Remarks:
USCSLL PL PILocation and Description
17
21
14
15
2
NP
2
NP
NT
88
NT
NT
Depth: 20.0 to 21.5
Depth: 60.0 to 61.5
Depth: 25.0 to 26.0
Depth: 30.0 to 30.4
MC%-#200
40
30
20
10
Liquid Limit,
Plastic Limit, and
Plasticity Index
SILT
SILT
SILT
SILT
50
30
7
4
70 90
30
26
NT
NT
ML
ML
ML
ML
Contains fines nodules.
Sample No.: S-6
Sample No.: S-11
Sample No.: S-7
Sample No.: S-8
110
60
Source: HA-B3
Source: HA-B3
Source: HA-B4
Source: HA-B5
19
21
16
15
Sheet 2 of 3
Figure B-2Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
HA
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a
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CL-ML
CH o
r
O
H
ML or OL MH or OH
CL o
r
O
L
CL-ML
DR
A
F
T
50
Dashed line indicates the approximate
upper limit boundary for natural soils
10
LIQUID LIMIT
PL
A
S
T
I
C
I
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Y
I
N
D
E
X
Remarks:
USCSLL PL PILocation and Description
18 24 93
Depth: 3.0 to 3.5
MC%-#200
40
30
20
10
Liquid Limit,
Plastic Limit, and
Plasticity Index
LEAN CLAY
50
30
7
4
70 90
23 CL
Sample No.: G-1
110
60
Source: HA-TP4
42
Sheet 3 of 3
Figure B-2Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
HA
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A
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\
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9
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a
h
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t
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CL-ML
CH o
r
O
H
ML or OL MH or OH
CL o
r
O
L
CL-ML
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
0
0
#1
4
0
#1
0
0
#6
0
#3
0
#4
0
#2
0
#1
0
#4
PE
R
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3 2 1-
1
/
2
3/
4
1/
2
3/
8
6 1
Particle-Size
Analysis
% Sand
D30LL PI D85 D60 D50
D15 D10 Cc Cu
7.615
0.264
5.436
0.255
0.275
0.179
0.088
0.087
GRAIN SIZE - mm
% Silt % Clay% Gravel% Cobbles
Remarks:
USCSMC%
20.1
2.2
15.7
0.9
51.8
25.1
52.2
53.6
28.1
72.7
32.1
45.6
17
22
17
21
SM
ML
SM
SM
0.465
0.263
0.123
0.0
0.0
0.0
0.0
U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS HYDROMETER
Contains organic material.
Sheet 1 of 4
Figure B-3
Location and Description
SILTY SAND WITH GRAVEL
SILT WITH SAND
SILTY SAND WITH GRAVEL
SILTY SAND
Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
Depth: 2.5 to 4.0
Depth: 7.5 to 9.0
Depth: 35.0 to 36.0
Depth: 45.0 to 46.0
Source: HA-B1
Source: HA-B2
Source: HA-B2
Source: HA-B2
Sample No.: S-1
Sample No.: S-3
Sample No.: S-9
Sample No.: S-11
coarseCOBBLESGRAVEL
finemediumfinecoarse
SAND SILT OR CLAY
HA
G
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:
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95
100
0.0010.010.1110100
#2
0
0
#1
4
0
#1
0
0
#6
0
#3
0
#4
0
#2
0
#1
0
#4
PE
R
C
E
N
T
F
I
N
E
R
3 2 1-
1
/
2
3/
4
1/
2
3/
8
6 1
Particle-Size
Analysis
% Sand
D30LL PI D85 D60 D50
D15 D10 Cc Cu
3.090
5.911
1.023
0.346
0.316
0.129
0.180
0.123
0.086
GRAIN SIZE - mm
% Silt % Clay% Gravel% Cobbles
Remarks:
USCSMC%
0.0
11.2
17.6
5.1
8.6
75.2
60.0
53.1
91.4
13.5
22.4
41.8
24
17
15
70
ML
SM
SM
SM
0.478
0.525
0.227
0.0
0.0
0.0
0.0
U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS HYDROMETER
Contains significant organic material.
Sheet 2 of 4
Figure B-3
Location and Description
SILT
SILTY SAND
SILTY SAND WITH GRAVEL
SILTY SAND
Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
Depth: 55.0 to 56.5
Depth: 10.0 to 11.5
Depth: 30.0 to 30.4
Depth: 5.0 to 6.5
Source: HA-B2
Source: HA-B3
Source: HA-B3
Source: HA-B4
Sample No.: S-13
Sample No.: S-4
Sample No.: S-8
Sample No.: S-2
coarseCOBBLESGRAVEL
finemediumfinecoarse
SAND SILT OR CLAY
HA
G
R
A
I
N
S
I
Z
E
-
C
:
\
U
S
E
R
S
\
A
H
U
L
T
Z
\
O
N
E
D
R
I
V
E
-
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
O
M
\
D
E
S
K
T
O
P
\
H
C
_
L
I
B
R
A
R
Y
.
G
L
B
-
3
/
2
0
/
2
5
1
4
:
5
6
-
\
\
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
O
M
\
S
H
A
R
E
\
C
F
\
P
R
O
J
E
C
T
S
\
0
2
0
7
9
1
1
\
F
I
E
L
D
D
A
T
A
\
P
E
R
M
_
G
I
N
T
F
I
L
E
S
\
0
2
0
7
9
1
1
-
0
0
1
_
S
O
O
S
C
R
E
E
K
T
R
A
I
L
_
G
I
N
T
.
G
P
J
-
a
h
u
l
t
z
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
0
0
#1
4
0
#1
0
0
#6
0
#3
0
#4
0
#2
0
#1
0
#4
PE
R
C
E
N
T
F
I
N
E
R
3 2 1-
1
/
2
3/
4
1/
2
3/
8
6 1
Particle-Size
Analysis
% Sand
D30LL PI D85 D60 D50
D15 D10 Cc Cu
5.966
0.697
12.859
3.265
0.455
0.157
0.784
0.174
0.157
0.304 0.135 0.089 0.56 20.50
GRAIN SIZE - mm
% Silt % Clay% Gravel% Cobbles
Remarks:
USCSMC%
17.7
3.5
29.6
12.4
63.6
59.5
61.7
53.1
18.7
37.0
8.7
34.5
14
10
15
14
SM
SM
SP-SM
SM
0.834
0.243
1.831
0.285
0.0
0.0
0.0
0.0
U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS HYDROMETER
1.5-2" gravel omitted.
Sheet 3 of 4
Figure B-3
Location and Description
SILTY SAND WITH GRAVEL
SILTY SAND
POORLY GRADED SAND WITH SILT AND GRAVEL
SILTY SAND
Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
Depth: 15.0 to 16.5
Depth: 5.0 to 6.5
Depth: 15.0 to 16.5
Depth: 3.0 to 3.5
Source: HA-B4
Source: HA-B5
Source: HA-B5
Source: HA-TP1
Sample No.: S-5
Sample No.: S-2
Sample No.: S-5
Sample No.: G-1
coarseCOBBLESGRAVEL
finemediumfinecoarse
SAND SILT OR CLAY
HA
G
R
A
I
N
S
I
Z
E
-
C
:
\
U
S
E
R
S
\
A
H
U
L
T
Z
\
O
N
E
D
R
I
V
E
-
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
O
M
\
D
E
S
K
T
O
P
\
H
C
_
L
I
B
R
A
R
Y
.
G
L
B
-
3
/
2
0
/
2
5
1
4
:
5
6
-
\
\
H
A
L
E
Y
A
L
D
R
I
C
H
.
C
O
M
\
S
H
A
R
E
\
C
F
\
P
R
O
J
E
C
T
S
\
0
2
0
7
9
1
1
\
F
I
E
L
D
D
A
T
A
\
P
E
R
M
_
G
I
N
T
F
I
L
E
S
\
0
2
0
7
9
1
1
-
0
0
1
_
S
O
O
S
C
R
E
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K
T
R
A
I
L
_
G
I
N
T
.
G
P
J
-
a
h
u
l
t
z
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
0
0
#1
4
0
#1
0
0
#6
0
#3
0
#4
0
#2
0
#1
0
#4
PE
R
C
E
N
T
F
I
N
E
R
3 2 1-
1
/
2
3/
4
1/
2
3/
8
6 1
Particle-Size
Analysis
% Sand
D30LL PI D85 D60 D50
D15 D10 Cc Cu
24
0.731
0.027
19.000
0.121
0.004
1.911
0.002
0.359 0.146 0.095 0.31 46.45
GRAIN SIZE - mm
% Silt % Clay% Gravel% Cobbles
Remarks:
USCSMC%
3.2
0.0
39.1
51.6
6.7
52.4
38.0
45.2
8.5
55.3
14
23
5
SM
CL
SP-SM
42
0.238
0.007
4.411
0.0
0.0
0.0
U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS HYDROMETER
Contains organic material (roots). 2-3" gravel omitted.
Sheet 4 of 4
Figure B-3
Location and Description
SILTY SAND
LEAN CLAY
POORLY GRADED SAND WITH SILT AND GRAVEL
Project:
Location:
Project No.:
SOOS CREEK TRAIL
RENTON, WASHINGTON
0207911-001
Depth: 12.0 to 12.5
Depth: 3.0 to 3.5
Depth: 7.0 to 7.5
Source: HA-TP2
Source: HA-TP4
Source: HA-TP5
Sample No.: G-3
Sample No.: G-1
Sample No.: G-2
coarseCOBBLESGRAVEL
finemediumfinecoarse
SAND SILT OR CLAY
HA
G
R
A
I
N
S
I
Z
E
-
C
:
\
U
S
E
R
S
\
A
H
U
L
T
Z
\
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N
E
D
R
I
V
E
-
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A
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E
Y
A
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D
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H
.
C
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M
\
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T
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\
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_
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I
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R
A
R
Y
.
G
L
B
-
3
/
2
0
/
2
5
1
4
:
5
6
-
\
\
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A
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A
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D
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.
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\
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H
A
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\
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\
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\
0
2
0
7
9
1
1
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P
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G
I
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F
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\
0
2
0
7
9
1
1
-
0
0
1
_
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_
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.
G
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DR
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21312 30th Dr. SE, STE. 110, Bothell, WA 98021 | 425.774.0106 | hwageo.com
March 24, 2025
HWA Project No. 2011-085-23 Task 1000
Haley & Aldrich, Inc.
3131 Elliot Avenue, Suite 600
Seattle, Washington 98121
Attention: Mr. Micheal Liu, P.E.
Subject: Materials Laboratory Report
Corrosivity Testing
Soos Creek
Client Project No. 0203363-001 Task 001/01
Dear Mr. Liu:
In accordance with your request, HWA GeoSciences Inc. (HWA) performed laboratory testing
for the above referenced project. Herein we present the results of our laboratory analyses, which
are summarized in Table 1 and in the attached External Laboratory Test Results. The laboratory
testing program was performed in general accordance with your instructions and appropriate
ASTM and/or AASHTO Standards as outlined below.
SAMPLE DESCRIPTION: Three samples were delivered to our laboratory on February 26, 2025,
by Haley and Aldrich personnel. The samples were delivered in resealable plastic bags
designated with borehole identification and sample depth.
One sample was submitted for testing (HA-B2, G-1), and the remaining samples were retained as
backup. The sample submitted for testing was classified for engineering purposes in general
accordance with ASTM D2488. The soil description for the sample is as follows:
HA-B2, G-1 Very dark gray, silty SAND with gravel (SM)
PH AND RESISTIVITY TEST RESULTS: Testing was carried out on the selected sample using
AASHTO T288 and T289. The indicated pH and minimum resistivity of the sample are
summarized below in Table 1.
Table 1
pH and Minimum Soil Resistivity
Sample pH Minimum Resistivity
HA-B2, G-1 7.0 2,100 ohm-cm
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March 24, 2025
HWA Project No. 2011-085-23 T1000
T1000 Letter Report 2 HWA GeoSciences Inc.
EXTERNAL LABORATORY ANALYSIS: The selected sample was shipped to Soiltest in Moses
Lake, WA for sulfate and chloride testing. The results of their analysis can be found in
Appendix A – External Laboratory Test Results.
CLOSURE: Experience has shown that test values on soil and other natural materials vary with
each representative sample. As such, HWA has no knowledge as to the extent and quantity of
material the tested samples may represent. HWA also makes no warranty as to how
representative either the samples tested or the test results obtained are to actual field conditions.
It is a well-established fact that sampling methods present varying degrees of disturbance that
affect sample representativeness.
No copy should be made of this report except in its entirety.
We appreciate the opportunity to provide laboratory testing services on this project. Should you
have any questions or comments, or if we may be of further service, please call.
HWA GEOSCIENCES INC.
Alex Hodges Chad McMullen, P.E.
Materials Laboratory Supervisor Quality Assurance Manager
Attachments:
Appendix A External Laboratory Test Results
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APPENDIX A
External Laboratory Test Results
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HWA GEOSCIENCES
21312 30TH DRIVE SE, STE 110
BOTHELL , WA 98021
3/17/2025
Soil
NO 2011-085 T1000
HA-B2 G-1
S25-03556
Date Received:
Grower:
Sampled By:
Field:
Laboratory #:
Test Results
Customer Account #:
Customer Sample ID:
Other Tests:
Chloride mg/kgSoluble I 58 pH 1:1
E.C. 1:1 m.mhos/cm
Est Sat Paste E.C. m.mhos/cm
Effervescence Lbs/Acre
Ammonium - N mg/kg
%Organic Matter W.B.ENR:
Nitrate-N
lbs/acremg/kg
Depth
inches
Sulfate-S
mg/kg
Moisture
Inches
0 - 12 4
0
Totals 4
Sum of Tested N:lbs/acre N
$34.00This is your Invoice #: List Cost:K. Bair, PhD, CReviewed by:S25-03556 Account #:188200
We make every effort to provide an accurate analysis of your sample. For reasonable cause we will repeat tests, but because of factors beyond our control
in sampling procedures and the inherent variability of soil, our liability is limited to the price of the tests. Recommendations are to be used as general
guides and should be modified for specific field conditions and situations. Note: "u" indicates that the element was analyzed for but not detected
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APPENDIX C
Pile Capacities Figures
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Figure C-1
Soos Creek Trail Renton, WA
12-inch by 1/2-inch Thick Open-Ended Pipe Pile
0207911-000 4/25
300
320
340
360
380
0 50 100 150 200 250 300
El
e
v
a
t
i
o
n
(
F
e
e
t
)
Nominal Resistance (Kips)
12-inch by 1/2-inch Thick Open-Ended Pipe Pile
Nominal Skin Resistance - Strength
Limit State
Nominal Pile Resistance -Strength
Limit State
Nominal Skin Resistance - Extreme
Event Limit State
Nominal Pile Resistance - Extreme
Event Limit State
Notes:
1. The assumed ground elevation = 373 feet. (The minor differences in resistance based on varying slope elevations can be ignored.)
2. The net weight of the pile should be treated as a load applied to the top of pile. This load is not accounted for in this chart.
3. Pile analyzed is a single 12-inch diameter driven pipe pile.
4. This chart presents the unfactored, nominal resistance values.
5. For strenth limite state analysis, Table 10.5.5.2.3-1 of AASHTO LRFD indicates a minimum resistance factor of 0.4 should be applied. If a
WEAP analysis is performed, then a resistance factor of 0.5 may be used. A resistance factor of 1.0 should be applied for the extreme event
limit state.
6. A minimum resistance factor of 0.25 should be applied to uplift resistance for the strength limit state. A resistance factor of 0.8 should be
applied to uplift resistance for the extreme event limit state.
7. A downdrag load of 18 kips should be applied to the pile load for the extreme event.
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Figure C-2
Soos Creek Trail Renton, WA
24-inch by 1/2-inch Thick Open-Ended Pipe Pile
0207911-000 4/25
300
320
340
360
380
0 100 200 300 400 500 600 700 800
El
e
v
a
t
i
o
n
(
F
e
e
t
)
Nominal Resistance (Kips)
24-inch by 1/2-inch Thick Open-Ended Pipe Pile
Nominal Skin Resistance - Strength
Limit State
Nominal Total Resistance - Strength
Limit State
Nominal Skin Resistance - Extreme
Event Limit State
Nominal Total Resistance - Extreme
Event Limit State
.Notes:
1. The assumed ground elevation = 373 feet. (The minor differences in resistance based on varying slope elevations can be ignored.)
2. The net weight of the pile should be treated as a load applied to the top of pile. This load is not accounted for in this chart.
3. Pile analyzed is a single 24-inch diameter driven pipe pile.
4. This chart presents the unfactored, nominal resistance values.
5. For strenth limite state analysis, Table 10.5.5.2.3-1 of AASHTO LRFD indicates a minimum resistance factor of 0.4 should be applied. If a
WEAP analysis is performed, then a resistance factor of 0.5 may be used. A resistance factor of 1.0 should be applied for the extreme
event limit state.
6. A minimum resistance factor of 0.25 should be applied to uplift resistance for the strength limit state. A resistance factor of 0.8 should
be applied to uplift resistance for the extreme event limit state.
7. A downdrag load of 37 kips should be applied to the pile load for the extreme event.
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APPENDIX D
Slope Stability Results
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2.02.0
W
250.00 lbs/ft2
2.02.0
Phi
(°)
Cohesion
(psf)Strength TypeUnit Weight (lbs/
ft3)ColorMaterial Name
380Mohr-
Coulomb130Gravel Backfill
320Mohr-
Coulomb120Exsiting Fill
360Mohr-
Coulomb125Alluvium
380Mohr-
Coulomb130Till
Infinite
Strength150Concrete Block
Wall
Min FSMethod Name
2.0Spencer
2.0GLE / Morgenstern-Price
44
0
42
0
40
0
38
0
36
0
-40 -20 0 20 40 60 80 100
XX
Figure
04/2025Scale 1:2000207911-001
Modular Block Wall - Static
Soos Creek Trail
Renton, WA
D-1
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1.21.2
W
250.00 lbs/ft2
1.21.2
Phi
(°)
Cohesion
(psf)Strength TypeUnit Weight (lbs/
ft3)ColorMaterial Name
380Mohr-
Coulomb130Gravel Backfill
320Mohr-
Coulomb120Exsiting Fill
360Mohr-
Coulomb125Alluvium
380Mohr-
Coulomb130Till
Infinite
Strength150Concrete Block
Wall
Min FSMethod Name
1.2Spencer
1.1GLE / Morgenstern-Price
0.25
44
0
42
0
40
0
38
0
36
0
-40 -20 0 20 40 60 80 100
XX
Figure
04/2025Scale 1:2000207911-001
Modular Block Wall - Seismic
Soos Creek Trail
Renton, WA
D-2
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