REVIEWED BLD2023-0433+Geotechnical_Report+4.6.2023_5.56.02_PM+3468753.,.,.,.,.,.REVIEWED ,.,.,.,.,..
BY
CITY OF EDMONDS
BUILDING DEPARTMENT:
March 28, 2023
ES-9040
PNT Group, LLC
5603 — 230t" Street Southwest
Mountlake Terrace, Washington 98043
Attention: Mr. Peter Tang
Subject: Geotechnical Evaluation
Proposed Single -Family Residence
840 Daley Street
Edmonds, Washington
Reference: Pacific Coast Surveys, Inc.
Topographic Survey, dated January 31, 2023
Tang Residence Option "B"
Earth
Solutions
NW«C
Earth Solutions NW LLC
Geotechnical Engineering, Construction
Observation/Testing and Environmental Services
RECEIVED
Apr 212023
DEVELOPMENT SERVICES
DEPARTMENT
BLD2023-0433
James P. Minard
Geologic Map of the Edmonds East and Part of the Edmonds West Quadrangles
Washington, 1983
United States Department of Agriculture (USDA)
Web Soil Survey (WSS)
Department of Ecology
Stormwater Management Manual for Western Washington
Amended December 2014
City of Edmonds
Edmonds Stormwater Addendum, dated June 30, 2022
Edmonds City Code
Chapter 18.30 (Stormwater Management)
Chapter 23.80 (Geologically Hazard Areas)
Dear Mr. Tang:
As requested, Earth Solutions NW, LLC (ESNW) has prepared this geotechnical evaluation for
the proposed single-family residence. As part of our scope of services, we completed a
subsurface exploration, laboratory and engineering analyses, and prepared this written report
with our findings and recommendations for the proposed project. Based on our evaluation, the
proposed project is feasible from a geotechnical standpoint.
15365 N.E. 90th Street, Suite 100 • Redmond, WA 98052 • (425) 449-4704 0 FAX (425) 449-4711
PNT Group, LLC
March 28, 2023
Protect Description
ES-9040
Page 2
The subject site is at 840 Daley Street in Edmonds, Washington, as illustrated on the attached
Vicinity Map (Plate 1). The site consists of one tax parcel (Snohomish County parcel number
00434208101000). The site is currently developed with a single-family residence and associated
improvements. The site topography gently descends to the west; a steep slope area is located
approximately 50 to 75 feet west of the subject site.
We understand the subject site will be redeveloped with a new single-family residence and
associated improvements. Grading activities will likely include cuts of up to about four feet to
establish the planned building alignments. Site improvements will also include underground utility
installations.
We understand the proposed residential structure will consist of relatively lightly loaded wood
framing supported on conventional foundations. Based on experience with similar projects, we
anticipate wall loads will be on the order of 1 to 2 kips per linear foot, isolated footing loads will
be less than 20 kips, and we anticipate slab -on -grade loading of 150 pounds per square foot
(psf).
If the above design assumptions are incorrect or change, ESNW should be contacted to review
the recommendations in this report. ESNW should review the final design to verify the
geotechnical recommendations provided in this report have been incorporated into the plans.
Subsurface Conditions
As part of this geotechnical evaluation, an ESNW representative observed, logged, and sampled
three hand auger borings on January 31, 2023, advanced at accessible locations within the
proposed development area, using hand tools and a half -inch diameter steel T-probe to probe
the subgrade of the test holes. The approximate locations of the hand auger borings are depicted
on the Hand Auger Boring Location Plan (Plate 2). Please refer to the hand auger boring logs
provided as an attachment to this report for a more detailed description of subsurface conditions.
Representative soil samples collected at the test pit locations were analyzed in general
accordance with the Unified Soil Classification System (USCS) and USDA methods and
procedures.
Topsoil
Topsoil was observed extending to depths of approximately four to six inches below the existing
ground surface (bgs). The topsoil was characterized by dark brown color and fine organic
material.
Native Soil
Underlying the topsoil, native soil at the test pit locations was observed to consist of poorly graded
sand with and without silt (USCS: SP-SM and SP, respectively). Overall soil relative density
generally increased with depth, becoming medium dense to dense at about one to two and one-
half feet bgs.
Earth Solutions NW. LLC
PNT Group, LLC
March 28, 2023
Geologic Setting
ES-9040
Page 3
The referenced geologic map resource identifies Vashon advance outwash deposits (Qva)
across the site and transitional bed deposits (Qtb) downslope of the site to the west, near the toe
of the adjacent steep slope area. As reported on the geologic map resource, advance outwash
is characterized as mostly clean and well -stratified sand with some pebbles. Transitional bed
deposits are glacial and nonglacial deposits that occur beneath the Vashon advance outwash
and consist mostly of clay, silt, and fine to very fine sand.
The referenced WSS identifies Alderwood-urban land complex as the primary soil unit underlying
the subject site with Alderwood-Everett gravelly sandy loam mapped to the southwest of the site.
Based on our field observations, native soils on the subject site are generally consistent with
Alderwood-Everett series soil.
Groundwater
Groundwater seepage was not observed at the hand auger boring locations during the fieldwork
(January 2023). However, zones of groundwater seepage may be present deeper, particularly
near the contact with the deeper transitional bed deposits. Groundwater seepage rates and
elevations fluctuate depending on many factors, including precipitation duration and intensity, the
time of year, and soil conditions.
Geologically Hazardous Areas Assessment
As part of this geotechnical evaluation, the referenced chapter of the ECC was reviewed. Based
on our investigation and review, the following topics related to development plans and site
conditions are addressed:
Erosion Hazard Areas — ECC 23.80.020.A.
With respect to erosion hazard areas, section 23.80.020 of the ECC defines erosion hazards as
"at least those areas identified by the U.S. Department of Agriculture's Natural Resources
Conservation Service as having a `moderate to severe', `severe', or `very severe' rill and inter -rill
erosion hazard. Erosion hazard areas are also those areas impacted by shoreland and/or stream
bank erosion. Within the city of Edmonds, erosion hazard areas include:
1. Those areas of the city of Edmonds containing soils that may experience severe to very
severe erosion hazard. This group of soils includes, but is not limited to, the following
when they occur on slopes of 15 percent or greater:
a. Alderwood soils (15 to 25 percent slopes);
b. Alderwood/Everett series (25 to 70 percent slopes), and;
c. Everett series (15 to 25 percent slopes).
Earth Solutions NW. LLC
PNT Group, LLC
March 28, 2023
ES-9040
Page 4
2. Coastal and stream erosion areas which are subject to the impacts from lateral erosion
related to moving water such as stream channel migration and shoreline retreat;
3. Any area with slopes of 15 percent or greater and impermeable soils interbedded with
granular soils and springs or ground water seepage, and;
4. Areas with significant visible evidence of ground water seepage, and which also include
existing landslide deposits regardless of slope."
Based on the ECC definition, the site does not contain any erosion hazard areas; the steep slope
area approximately 50 to 75 feet west of the subject site would classify as an erosion hazard.
Landslide Hazard Areas — ECC 23.80.020.113.
With respect to landslide hazard areas, section 23.80.020 of the ECC defines landslide hazard
areas as areas potentially subject to landslides based on a combination of geologic, topographic,
and hydrologic factors. They include areas susceptible because of any combination of soil, slope
gradient, slope aspect, structure, hydrology, or other factors. Within the city of Edmonds,
landslide hazard areas specifically include:
1. Areas of ancient or historic failures in Edmonds which include all areas within the earth
subsidence and landslide hazard area as identified in the 1979 report of Robert Lowe
Associates and amended by the 1985 report of GeoEngineers, Inc., and further discussed
in the 2007 report by Landau Associates;
2. Coastal areas mapped as class U (unstable), UOS (unstable old slides) and URS
(unstable recent slides) in the Department of Ecology Washington coastal atlas;
3. Areas designated as quaternary slumps, earthflows, mudflows, or landslides on maps
published by the United States Geological Survey or Washington State Department of
Natural Resources;
4. Any slope of 40 percent or steeper that exceeds a vertical height of 10 feet over a 25-foot
horizontal run. Except for rockeries that have been engineered and approved by the
engineer as having been built according to the engineered design, all other modified
slopes (including slopes where there are breaks in slopes) meeting overall average
steepness and height criteria should be considered potential landslide hazard areas;
5. Any slope with all three of the following characteristics:
a. Slopes steeper than 15 percent;
b. Hillsides intersecting geologic contacts with relatively permeable sediment overlying a
relatively impermeable sediment, and;
c. Springs or ground water seepage.
Earth Solutions NW. LLC
PNT Group, LLC
March 28, 2023
ES-9040
Page 5
6. Any area potentially unstable as a result of rapid stream incision or stream bank erosion;
7. Any area located on an alluvial fan, presently subject to, or potentially subject to,
inundation by debris flow or deposition of stream -transported sediments, and;
8. Any slopes that have been modified by past development activity that still meet the slope
criteria.
Based on the ECC definition, the site does not contain any landslide hazard areas; the steep
slope area approximately 50 to 75 feet west of the subject site appears to classify as landslide
hazard area.
Temporary Excavations
For temporary cuts taller than four feet, we recommend sloping or benching the cuts with a 1 H:1 V
gradient. Steeper inclinations can be evaluated by ESNW during construction based on exposed
soil conditions.
Structural Fill
Structural fill is defined as compacted soil placed in foundation, slab -on -grade, roadway,
permanent slope, retaining wall, and utility trench backfill areas. Structural fill placed and
compacted during site grading activities should meet the following specifications and guidelines:
• Structural fill material
• Moisture content
• Relative compaction
• Loose lift thickness (maximum)
Granular soil*
At or slightly above optimum**
95 percent (Modified Proctor)
12 inches
Existing soil may not be suitable for use as structural fill unless at (or slightly above) the optimum moisture content
at the time of placement and compaction.
** Soil shall not be placed dry of optimum and should be evaluated by ESNW during construction.
With respect to underground utility installations and backfill, local jurisdictions may dictate the soil
type(s) and compaction requirements. Unsuitable material or debris must be removed from
structural areas if encountered.
Earth Solutions NW. LLC
PNT Group, LLC ES-9040
March 28, 2023 Page 6
Foundations
The proposed structure can be supported on conventional spread and continuous footings
bearing on undisturbed, competent native soil, compacted native soil, or new structural fill.
Competent native soils, suitable for support of the foundation, should be encountered beginning
at depths of approximately one to two and one-half feet bgs. Where loose or unsuitable soil
conditions are encountered at foundation subgrade elevations during site preparation activities,
compaction of the soils to the specifications of structural fill, or overexcavation and replacement
with granular structural fill will be necessary. Compaction of the soil to the levels necessary for
use as structural fill may be difficult during wet weather conditions. Organic material exposed at
foundation subgrade elevations must be removed and grades restored with structural fill.
Provided the structure will be supported as described above, the following parameters can be
used for design of the new foundations:
• Allowable soil bearing capacity 2,500 psf
• Passive earth pressure 300 pcf (equivalent fluid)
• Coefficient of friction 0.40
The passive earth pressure and coefficient of friction values include a safety factor of 1.5. A one-
third increase in the allowable soil bearing capacity can be assumed for short-term wind and
seismic loading conditions.
With structural loading as expected, total settlement in the range of one inch is anticipated, with
differential settlement of about one-half inch. The majority of the settlements should occur during
construction, as dead loads are applied.
Slab -on -Grade Floors
Slab -on -grade floors for the proposed residential structure should be supported on a well -
compacted, firm, and unyielding subgrade. Where feasible, native soils exposed at the slab -on -
grade subgrade level can likely be compacted in -situ to the specifications described in this
section. Unstable or yielding areas of subgrade should be recompacted, or overexcavated and
replaced with suitable structural fill, prior to construction of the slab.
A capillary break consisting of a minimum of four inches of free -draining crushed rock or gravel
should be placed below the slab. The free -draining material should have a fines content of 5
percent or less (where the fines content is defined as the percent passing the Number 200 sieve,
based on the minus three -quarter -inch fraction). In areas where slab moisture is undesirable,
installation of a vapor barrier below the slab should be considered. If a vapor barrier is utilized,
it should be a material specifically designed for use as a vapor barrier and should be installed in
accordance with manufacturer specifications.
Earth Solutions NW. LLC
PNT Group, LLC
March 28, 2023
Retaining Walls
ES-9040
Page 7
Retaining walls must be designed to resist earth pressures and applicable surcharge loads. The
following parameters may be used for design:
• Active earth pressure (unrestrained condition)
• At -rest earth pressure (restrained condition)
• Traffic surcharge (passenger vehicles)
• Passive earth pressure
• Coefficient of friction
• Seismic surcharge
Where applicable.
** Where H equals the retained height (in feet).
35 pcf (equivalent fluid)
55 pcf
70 psf (rectangular distribution)*
300 pcf (equivalent fluid)
M1
8H psf**
A factor -of -safety of 1.5 has been applied to the passive earth pressure and coefficient of friction
values provided in this section. The above design parameters are based on a level backfill
condition and level grade at the wall toe. Revised design values will be necessary if sloping
grades are to be used above or below retaining walls. Additional surcharge loading from adjacent
foundations, sloped backfill, or other relevant loads should be included in the retaining wall
design.
Retaining walls should be backfilled with free -draining material that extends along the height of
the wall and a distance of at least 18 inches behind the wall. In lieu of 18 inches of a free draining
material, a drainage mat can be considered. ESNW should evaluate the suitability of drainage
mat application during construction. The upper 12 inches of the wall backfill may consist of a
less permeable soil, if desired. A perforated drainpipe should be placed along the base of the
wall and connected to an approved discharge location. A typical retaining wall drainage detail is
provided on Plate 3. If drainage is not provided, hydrostatic pressures should be included in the
wall design.
Seismic Design
The 2018 International Building Code (2018 IBC) recognizes the most recent edition of the
Minimum Design Loads for Buildings and Other Structures manual (ASCE 7-16) for seismic
design, specifically with respect to earthquake loads. Based on the soil conditions encountered
at the test locations, the Site Class D is recommended for seismic design per the 2018 IBC.
Earth Solutions NW. LLC
PNT Group, LLC
March 28, 2023
Liquefaction
ES-9040
Page 8
Liquefaction is a phenomenon where saturated and loose cohesionless soil suddenly loses
internal strength and behaves as a fluid. This behavior is in response to increased pore water
pressures resulting from an earthquake or another intense ground shaking. In our opinion, site
susceptibility to liquefaction may be considered low. The depth of the regional groundwater table
and the relative density of the native soil were the primary bases for this opinion.
Drainage
Zones of perched groundwater seepage should be anticipated in site excavations depending on
the time of year grading operations take place. Temporary measures to control surface water
runoff and groundwater during construction would likely involve passive elements such as
interceptor trenches and sumps. ESNW should be consulted during preliminary grading to
identify areas of seepage and to provide recommendations to reduce the potential for instability
related to seepage effects.
Finish grades should be designed to direct surface water away from structures and slopes.
Grades adjacent to structures and slopes should be sloped away at a gradient of at least 2
percent for a horizontal distance of up to 10 feet or the maximum allowed by adjacent structures.
In our opinion, foundation drains should be installed along building perimeter footings. A typical
footing drain detail is provided on Plate 4.
Infiltration and LID Evaluation
As indicated in the Subsurface Conditions section, native soils encountered during our fieldwork
were characterized primarily as sand. While native sand soil may exhibit a moderate to good
infiltration capacity, we do not recommend infiltrating site runoff due to the proximity to the steep
slope area to the west of the site. Based on topography and geologic mapping, attempted
infiltration would move laterally along the deeper fine-grained and pose a risk to stability of the
nearby steep slope area.
Pursuant to City of Edmonds stormwater management requirements, implementation of on -site
stormwater BMPs are required for proposed developments in accordance with specified
thresholds, standards, and lists. The intent of BMP implementation is to infiltrate, disperse, and
retain stormwater runoff on site to the extent feasible. The table below summarizes our
evaluation of low impact development methods, as outlined in the referenced stormwater manual,
from a geotechnical standpoint. It is instructed in the referenced stormwater manual that BMPs
are to be considered in the order listed (from top to bottom) for each surface type, and the first
BMP that is determined to be viable should be used. For completeness, however, we have
evaluated each listed BMP for the proposed surface types.
Earth Solutions NW. LLC
PNT Group, LLC
March 28, 2023
ES-9040
Page 9
BMP
Viable?
Limitations or
Infeasibility Criteria
Lawns and Landscaped Areas
T5.13: Post -construction soil quality
Yes
None.
and depth (Volume V, Chapter 5)
Roofs
T5.30: Full dispersion (Volume V,
Maybe*
Limitation: Adequate vegetative flow paths may not be
Chapter 5)
available.
T5.10A: Downspout full infiltration
NO
Infeasibility: Not recommended due to adjacent steep slope
systems (Volume III, Chapter 3)
area and risk of causing instability.
Roofs
Bioretention (Volume V, Chapter 7)
No
Infeasibility: Not recommended due to adjacent steep slope
area and risk of causing instability.
T5.10B: Downspout dispersion
Maybe*
Limitation: Adequate vegetative flow paths may not be
systems (Volume III, Chapter 3)
available.
T5.10C: Perforated stub -out
NO
Infeasibility: Not recommended due to adjacent steep slope
connections (Volume III, Chapter 3)
area and risk of causing instability.
T5.30: Full dispersion (Volume V,
Maybe*
Limitation: Adequate vegetative flow paths may not be
Chapter 5)
available.
T5.15: Permeable pavement
NO
Infeasibility: Not recommended due to adjacent steep slope
(Volume V, Chapter 5)
area and risk of causing instability.
Bioretention (Volume V, Chapter 7)
No
Infeasibility: Not recommended due to adjacent steep slope
area and risk of causing instability.
T5.12: Sheet flow dispersion
Limitation: Adequate vegetative flow paths may not be
T5.11: Concentrated flow dispersion
Maybe*
available.
(Volume V, Chapter 5)
* Viability to be determined by storm designer.
Limitations
This geotechnical evaluation report has been prepared for the exclusive use of Mr. Peter Tang
and his representatives. The recommendations and conclusions provided in this report are
professional opinions consistent with the level of care and skill that is typical of other members in
the profession currently practicing under similar conditions in this area. A warranty is not
expressed or implied. Variations in the soil and groundwater conditions observed at the test sites
may exist and may not become evident until construction. ESNW should reevaluate the
conclusions in this report if variations are encountered.
Earth Solutions NW. LLC
PNT Group, LLC
March 28, 2023
Additional Services
ES-9040
Page 10
ESNW should be retained to provide additional geotechnical services in association with this
project, including testing and consulting services during construction. ESNW should have an
opportunity to review final project plans with respect to geotechnical recommendations provided
in this letter.
We trust this letter meets your current needs. Should you have questions, or if any additional
information is required, please call.
Sincerely,
EARTH SOLUTIONS NW, LLC
03/28/2023
Henry T. Wright, P.E.
Associate Principal Engineer
Attachments: Plate 1 — Vicinity Map
Plate 2 — Hand Auger Boring Location Plan
Plate 3 — Retaining Wall Drainage Detail
Plate 4 — Footing Drain Detail
Hand Auger Boring Logs
Grain Size Distribution
cc: RAM Engineering, Inc.
Attention: Mr. Rob Long, P.E. (Email only)
Earth Solutions NW. LLC
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Open StreetMap.org
40
Vicinity Map
Tang Residence
Edmonds, Washington
Drawn MRS
Date 02/23/2023
Proj. No. 9040
NOTE: This plate may contain areas of color. ESNW cannot be
responsible for any subsequent misinterpretation of the information
Checked KTK
Date Feb. 2023
Plate 1
resulting from black & white reproductions of this plate.
DALEY STREET
174
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SPRAGUE
LEGEND
HA-1I Approximate Location of
• — ESNW Hand Auger Boring,
Proj. No. ES-9040, Jan. 2023
Subject Site
Existing Building
NOTE: The graphics shown on this plate are not intended for design
purposes or precise scale measurements, but only to illustrate the
approximate test locations relative to the approximate locations of
existing and / or proposed site features. The information illustrated
is largely based on data provided by the client at the time of our
study. ESNW cannot be responsible for subsequent design changes
or interpretation of the data by others.
NORTH
0 50 100 200
1 "=100' � �
Scale in Feet
Hand Auger Boring Location Plan
Tang Residence
Edmonds, Washington
NOTE: This plate may contain areas of color. ESNW cannot be Drawn MRS Date 02/23/2023 Pro' No. 9040
responsible for any subsequent misinterpretation of the information 1
resulting from black & white reproductions of this plate. Checked KTK Date Feb. 2023 Plate 2
18" Min.
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NOTES:
• Free -draining Backfill should consist
of soil having less than 5 percent fines.
Percent passing No. 4 sieve should be
25 to 75 percent.
• Sheet Drain may be feasible in lieu
of Free -draining Backfill, per ESNW
recommendations.
• Drain Pipe should consist of perforated,
rigid PVC Pipe surrounded with 1-inch
Drain Rock.
LEGEND:
ffiFree -draining Structural Backfill
o
1-inch Drain Rock
Structural
Fill
Perforated Rigid Drain Pipe
(Surround in Drain Rock)
SCHEMATIC ONLY - NOT TO SCALE
NOT A CONSTRUCTION DRAWING
Retaining Wall Drainage Detail
Tang Residence
Edmonds, Washington
Drawn MRS Date 02/23/2023 Proj. No. 9040
Checked KTK Date Feb.2023 Plate 3
Perforated Rigid Drain Pipe
(Surround in Drain Rock)
NOTES:
• Do NOT tie roof downspouts
to Footing Drain.
• Surface Seal to consist of
12" of less permeable, suitable
soil. Slope away from building.
LEGEND:
Surface Seal: native soil or
other low -permeability material
B.* - _- - - _... " - "
1-inch Drain Rock
SCHEMATIC ONLY - NOT TO SCALE
NOT A CONSTRUCTION DRAWING
Earth
Solutions
NW uc
Footing Drain Detail
Tang Residence
Edmonds, Washington
Drawn MRS Date 02/23/2023 Proj. No. 9040
Checked KTK Date Feb.2023 Plate 4
W
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Well -graded gravel with
Moisture Content
Symbols
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Cement grout
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the touch
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surface seal
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o
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Terms Describing Relative Density and Consistency
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Coarse -Grained Soils: Test Symbols & Units
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a)Very
Dense _> 50
O U)
PID = Photoionization Detector (ppm)
co
a�
'.:'
.
SM
Silty sand with or without
o
Lo c
c
:;:
.::'•:.
;..
gravel
Fine -Grained Soils: OC = Organic Content (%)
e
.
•;.
Consistency SPT blows/foot CEC = Cation Exchange Capacity (meq/100 g)
:
Very Soft < 2
�
�
SC
Clayey sand with or
LL = Liquid Limit (%)
Soft 2 to 3
^
without gravel
Medium Stiff 4 to 7 PL = Plastic Limit (%)
(%)
Stiff 8 to 14 PI = Plasticity IndexLO
CD
Silt with or without sand
IVIL
or gravel; sandy or
Very Stiff 15 to 29
gravelly silt
Hard _> 30
0
0 0
U 0
F///
Clay of low to medium
Y
Component Definitions
>
a)—.1
plasticity; plasticity; lean clay with
cn
M t.
or without sand or gravel;
Descriptive Term Size Range and Sieve Number
00
cn E
sandy or gravelly lean clay
Boulders Larger than 12"
— —
_
�
rn .
— J
U .5
Cobbles 3" to 12"
�o
_
OL
Organic clay or silt of
Zo
—
low plasticity
Gravel 3" to No. 4 (4.75 mm)
-0 to
J
�_
—
Coarse Gravel 3" to 3/4"
Fine Gravel 3/4" to No. 4 (4.75 mm)
Elastic silt with or without
d
Sand No. 4 (4.75 mm) to No. 200 (0.075 mm)
0
0
o
MH
sand or gravel; sandy or
Coarse Sand No. 4 (4.75 mm) to No. 10 (2.00 mm)
c O
(n g
gravelly elastic silt
Medium Sand No. 10 (2.00 mm) to No. 40 (0.425 mm)
IL 2
>, -
Fine Sand No. 40 (0.425 mm) to No. 200 (0.075 mm)
0 °o U O
Clay of high plasticity;
Silt and Clay Smaller than No. 200 (0.075 mm)
o
-0 LO
CH
fat clay with or without
Modifier Definitions
o
E
sand or gravel; sandy or
J
gravelly fat clay
—_
Percentage by
fn
Weight (Approx.) Modifier
CY
OH
Organic clay or silt of
medium to high plasticity
< 5 Trace (sand, silt, clay, gravel)
5 to 14 Slightly (sandy, silty, clayey, gravelly)
o>
ca o
PT
Peat, muck, and other
15 to 29 Sandy, silty, clayey, gravelly
=
�U)
— =
highly organic soils
Q
_> 30 Very (sandy, silty, clayey, gravelly)
Classifications of soils in this geotechnical report and as shown on the exploration logs are based on visual
—
field and/or laboratory observations, which include density/consistency, moisture condition, grain size, and
ii
FILL
Made Ground
plasticity estimates, and should not be construed to imply field or laboratory testing unless presented herein.
Visual -manual and/or laboratory classification methods of ASTM D2487 and D2488 were used as an
identification guide for the Unified Soil Classification System.
Earth
Solutions
NW L�c
Earth Solutions NWLLC
Geotechnical Engineering, Construction
Observation/Testing and Environmental Services
EXPLORATION LOG KEY
r Earth Solutions NW, LLC
15365 N.E. 90th Street, Suite 100
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
BORING NUMBER HA-1
PAGE 1 OF 1
PROJECT NUMBER ES-9040 PROJECT NAME Tang Residence
DATE STARTED 1/31/23 COMPLETED 1/31/23 GROUND ELEVATION
DRILLING CONTRACTOR ESNW Rep LATITUDE 47.81363 LONGITUDE-122.36824
LOGGED BY KTK CHECKED BY HTW GROUND WATER LEVEL:
NOTES S7 AT TIME OF DRILLING
SURFACE CONDITIONS Grass AFTER DRILLING
_
wJ
p
0.0
w
~Lu
CO
d7
Q Z
TESTS
_
0_ O
fy
0
MATERIAL DESCRIPTION
TPSL
.`=: `. 0.3
Dark brown TOPSOIL
-
Dark brown poorly graded SAND with silt, medium dense, moist to wet
-becomes brown
SP_
-probed 8"
MC = 11.5
_
Fines = 8.9
SM
[USDA Classification: gravelly SAND]
2.5
-becomes tan, medium dense to dense, moist
-probed 4"
MC = 7.1
3.5
Hand auger boring terminated at 3.5 feet below existing grade. No groundwater encountered
during excavation. No caving observed.
LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed.
Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a
standalone document. Refer to the text of the geotechnical report for a complete understanding
of subsurface conditions.
r Earth Solutions NW, LLC
15365 N.E. 90th Street, Suite 100
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
BORING NUMBER HA-2
PAGE 1 OF 1
PROJECT NUMBER ES-9040 PROJECT NAME Tang Residence
DATE STARTED 1/31/23 COMPLETED 1/31/23 GROUND ELEVATION
DRILLING CONTRACTOR ESNW Rep LATITUDE 47.8136 LONGITUDE-122.36802
LOGGED BY KTK CHECKED BY HTW GROUND WATER LEVEL:
NOTES S7 AT TIME OF DRILLING
SURFACE CONDITIONS Grass AFTER DRILLING
w
_
w
~Lu
Uj CO
TESTS
_
O
J
Q
Q z
0
0.5
SM
MC = 7.2
SP
2.5 SM
MC = 7.0 3.5
MATERIAL DESCRIPTION
Dark brown TOPSOIL (Fill)
Dark brown poorly graded SAND with silt, loose, moist
Brown poorly graded SAND with silt, medium dense, moist
-probed 8"
Test pit terminated at 3.5 feet below existing grade. No groundwater encountered during
excavation. No caving observed.
LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed.
Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a
standalone document. Refer to the text of the geotechnical report for a complete understanding
of subsurface conditions.
r Earth Solutions NW, LLC
15365 N.E. 90th Street, Suite 100
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
BORING NUMBER HA-3
PAGE 1 OF 1
PROJECT NUMBER ES-9040 PROJECT NAME Tang Residence
DATE STARTED 1/31/23 COMPLETED 1/31/23 GROUND ELEVATION
DRILLING CONTRACTOR ESNW Rep LATITUDE 47.81344 LONGITUDE-122.36808
LOGGED BY KTK CHECKED BY HTW GROUND WATER LEVEL:
NOTES S7 AT TIME OF DRILLING
SURFACE CONDITIONS Grass AFTER DRILLING
_
wJ
p
0.0
w
~Lu
CO
d7
Q Z
TESTS
_
Q O
fy
0
MATERIAL DESCRIPTION
TPSL
.'—.
Dark brown TOPSOIL
0.5
Brown poorly graded SAND with silt, loose, moist
SP-
_
SM
-probed 4"
2.5
MC = 6.3
2 5
Tan poorly graded SAND, medium dense to dense, moist
SP
[USDA Classification: gravelly SAND]
MC = 5.9
3.5
Fines = 1.9
Hand auger boring terminated at 3.5 feet below existing grade. No groundwater encountered
during excavation. No caving observed.
LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed.
Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a
standalone document. Refer to the text of the geotechnical report for a complete understanding
of subsurface conditions.
Earth Solutions NW, LLC GRAIN SIZE DISTRIBUTION
15365 N.E. 90th Street, Suite 100
WWI Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
PROJECT NUMBER ES-9040 PROJECT NAME Tang Residence
U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS I HYDROMETER
6 4 3 2 1 1 /23/8 3 4 6 810 1416 20 30 40 50 60 100140 200
100
95
90
85
80
75
70
65
H
cD
60
w
� 55
m
w 50
z
LL
45
z
w
40
w
a
35
30
25
20
15
10
5
0
100 10 1 0.1 0.01 0.001
GRAIN SIZE IN MILLIMETERS
COBBLES
GRAVEL
SAND
SILT OR CLAY
coarse fine
coarse medium fine