HomeMy WebLinkAboutEx_09_Geotechnical_ReportEarthSolutionsNWLLC
EarthSolutionsNWLLC
Geotechnical Engineering
Construction Observation/Testing
Environmental Services
15365 NE 90th Street,Suite 100 •Redmond,WA 98052 •(425)449-4704
3130 Varney Lane,Suite 105 •Pasco,WA 99301 •(509)905-0275
esnw.com
GEOTECHNICAL ENGINEERING STUDY
PROPOSED BALES PLACE SHORT PLAT
11806 SOUTHEAST 192 STREET
RENTON,WASHINGTON
ES-9583
ND
Exhibit 9
RECEIVED
02/20/2025 NPerry
PLANNING DIVISIONDocusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
PREPARED FOR
LAKE SAMISH, LLC
February 21, 2024
_______________________
John M. Neer, G.I.T.
Staff Geologist
_______________________
Henry T. Wright, P.E.
Associate Principal Engineer
GEOTECHNICAL ENGINEERING STUDY
PROPOSED BALES PLACE SHORT PLAT
11806 SOUTHEAST 192ND STREET
RENTON, WASHINGTON
ES-9583
Earth Solutions NW, LLC
15365 NE 90th Street, Suite 100 • Redmond, WA 98052 • (425) 449-4704
3130 Varney Lane, Suite 105 • Pasco, WA 99301 • (509) 905-0275
esnw.com
02/21/2024
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
Geotechnical-Engineering Report
Important Information about This
Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes.
While you cannot eliminate all such risks, you can manage them. The following information is provided to help.
The Geoprofessional Business Association (GBA) has prepared this advisory to help you – assumedly a client representative – interpret and apply this geotechnical-engineering report as effectively as possible. In that way, you can benefit from a lowered exposure to problems associated with subsurface conditions at project sites and development of them that, for decades, have been a principal cause of construction delays, cost overruns, claims, and disputes. If you have questions or want more information about any of the issues discussed herein, contact your GBA-member geotechnical engineer. Active engagement in GBA exposes geotechnical engineers to a wide array of risk-confrontation techniques that can be of genuine benefit for everyone involved with a construction project.
Understand the Geotechnical-Engineering Services Provided for this ReportGeotechnical-engineering services typically include the planning, collection, interpretation, and analysis of exploratory data from widely spaced borings and/or test pits. Field data are combined with results from laboratory tests of soil and rock samples obtained from field exploration (if applicable), observations made during site reconnaissance, and historical information to form one or more models of the expected subsurface conditions beneath the site. Local geology and alterations of the site surface and subsurface by previous and proposed construction are also important considerations. Geotechnical engineers apply their engineering training, experience, and judgment to adapt the requirements of the prospective project to the subsurface model(s). Estimates are made of the subsurface conditions that will likely be exposed during construction as well as the expected performance of foundations and other structures being planned and/or affected by construction activities.
The culmination of these geotechnical-engineering services is typically a geotechnical-engineering report providing the data obtained, a discussion of the subsurface model(s), the engineering and geologic engineering assessments and analyses made, and the recommendations developed to satisfy the given requirements of the project. These reports may be titled investigations, explorations, studies, assessments, or evaluations. Regardless of the title used, the geotechnical-engineering report is an engineering interpretation of the subsurface conditions within the context of the project and does not represent a close examination, systematic inquiry, or thorough investigation of all site and subsurface conditions.
Geotechnical-Engineering Services are Performed for Specific Purposes, Persons, and Projects, and At Specific TimesGeotechnical engineers structure their services to meet the specific needs, goals, and risk management preferences of their clients. A geotechnical-engineering study conducted for a given civil engineer
will not likely meet the needs of a civil-works constructor or even a
different civil engineer. Because each geotechnical-engineering study
is unique, each geotechnical-engineering report is unique, prepared solely for the client.
Likewise, geotechnical-engineering services are performed for a specific
project and purpose. For example, it is unlikely that a geotechnical-
engineering study for a refrigerated warehouse will be the same as
one prepared for a parking garage; and a few borings drilled during
a preliminary study to evaluate site feasibility will not be adequate to
develop geotechnical design recommendations for the project.
Do not rely on this report if your geotechnical engineer prepared it:
• for a different client;
• for a different project or purpose;
• for a different site (that may or may not include all or a portion of
the original site); or
• before important events occurred at the site or adjacent to it;
e.g., man-made events like construction or environmental
remediation, or natural events like floods, droughts, earthquakes,
or groundwater fluctuations.
Note, too, the reliability of a geotechnical-engineering report can
be affected by the passage of time, because of factors like changed
subsurface conditions; new or modified codes, standards, or
regulations; or new techniques or tools. If you are the least bit uncertain
about the continued reliability of this report, contact your geotechnical
engineer before applying the recommendations in it. A minor amount
of additional testing or analysis after the passage of time – if any is
required at all – could prevent major problems.
Read this Report in Full
Costly problems have occurred because those relying on a geotechnical-
engineering report did not read the report in its entirety. Do not rely on
an executive summary. Do not read selective elements only. Read and refer to the report in full.
You Need to Inform Your Geotechnical Engineer About Change
Your geotechnical engineer considered unique, project-specific factors
when developing the scope of study behind this report and developing
the confirmation-dependent recommendations the report conveys.
Typical changes that could erode the reliability of this report include
those that affect:
• the site’s size or shape;
• the elevation, configuration, location, orientation,
function or weight of the proposed structure and
the desired performance criteria;
• the composition of the design team; or
• project ownership.
As a general rule, always inform your geotechnical engineer of project
or site changes – even minor ones – and request an assessment of their
impact. The geotechnical engineer who prepared this report cannot accept
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
responsibility or liability for problems that arise because the geotechnical engineer was not informed about developments the engineer otherwise would have considered.
Most of the “Findings” Related in This Report Are Professional Opinions
Before construction begins, geotechnical engineers explore a site’s
subsurface using various sampling and testing procedures. Geotechnical engineers can observe actual subsurface conditions only at those specific locations where sampling and testing is performed. The data derived from
that sampling and testing were reviewed by your geotechnical engineer,
who then applied professional judgement to form opinions about
subsurface conditions throughout the site. Actual sitewide-subsurface
conditions may differ – maybe significantly – from those indicated in
this report. Confront that risk by retaining your geotechnical engineer
to serve on the design team through project completion to obtain
informed guidance quickly, whenever needed.
This Report’s Recommendations Are Confirmation-Dependent
The recommendations included in this report – including any options or
alternatives – are confirmation-dependent. In other words, they are not
final, because the geotechnical engineer who developed them relied heavily
on judgement and opinion to do so. Your geotechnical engineer can finalize
the recommendations only after observing actual subsurface conditions
exposed during construction. If through observation your geotechnical
engineer confirms that the conditions assumed to exist actually do exist,
the recommendations can be relied upon, assuming no other changes have
occurred. The geotechnical engineer who prepared this report cannot assume responsibility or liability for confirmation-dependent recommendations if you fail to retain that engineer to perform construction observation.
This Report Could Be Misinterpreted
Other design professionals’ misinterpretation of geotechnical-
engineering reports has resulted in costly problems. Confront that risk
by having your geotechnical engineer serve as a continuing member of
the design team, to:
• confer with other design-team members;
• help develop specifications;
• review pertinent elements of other design professionals’ plans and
specifications; and
• be available whenever geotechnical-engineering guidance is needed.
You should also confront the risk of constructors misinterpreting this report. Do so by retaining your geotechnical engineer to participate in prebid and preconstruction conferences and to perform construction-phase observations.
Give Constructors a Complete Report and GuidanceSome owners and design professionals mistakenly believe they can shift unanticipated-subsurface-conditions liability to constructors by limiting the information they provide for bid preparation. To help prevent the costly, contentious problems this practice has caused, include the complete geotechnical-engineering report, along with any attachments or appendices, with your contract documents, but be certain to note
conspicuously that you’ve included the material for information purposes only. To avoid misunderstanding, you may also want to note that
“informational purposes” means constructors have no right to rely on
the interpretations, opinions, conclusions, or recommendations in the
report. Be certain that constructors know they may learn about specific
project requirements, including options selected from the report, only
from the design drawings and specifications. Remind constructors
that they may perform their own studies if they want to, and be sure to allow enough time to permit them to do so. Only then might you be in
a position to give constructors the information available to you, while
requiring them to at least share some of the financial responsibilities
stemming from unanticipated conditions. Conducting prebid and
preconstruction conferences can also be valuable in this respect.
Read Responsibility Provisions Closely
Some client representatives, design professionals, and constructors do
not realize that geotechnical engineering is far less exact than other
engineering disciplines. This happens in part because soil and rock on
project sites are typically heterogeneous and not manufactured materials
with well-defined engineering properties like steel and concrete. That
lack of understanding has nurtured unrealistic expectations that have
resulted in disappointments, delays, cost overruns, claims, and disputes.
To confront that risk, geotechnical engineers commonly include
explanatory provisions in their reports. Sometimes labeled “limitations,”
many of these provisions indicate where geotechnical engineers’
responsibilities begin and end, to help others recognize their own
responsibilities and risks. Read these provisions closely. Ask questions.
Your geotechnical engineer should respond fully and frankly.
Geoenvironmental Concerns Are Not Covered
The personnel, equipment, and techniques used to perform an
environmental study – e.g., a “phase-one” or “phase-two” environmental
site assessment – differ significantly from those used to perform a
geotechnical-engineering study. For that reason, a geotechnical-engineering
report does not usually provide environmental findings, conclusions, or
recommendations; e.g., about the likelihood of encountering underground
storage tanks or regulated contaminants. Unanticipated subsurface environmental problems have led to project failures. If you have not
obtained your own environmental information about the project site,
ask your geotechnical consultant for a recommendation on how to find
environmental risk-management guidance.
Obtain Professional Assistance to Deal with Moisture Infiltration and Mold
While your geotechnical engineer may have addressed groundwater,
water infiltration, or similar issues in this report, the engineer’s
services were not designed, conducted, or intended to prevent
migration of moisture – including water vapor – from the soil
through building slabs and walls and into the building interior, where
it can cause mold growth and material-performance deficiencies.
Accordingly, proper implementation of the geotechnical engineer’s recommendations will not of itself be sufficient to prevent moisture infiltration. Confront the risk of moisture infiltration by
including building-envelope or mold specialists on the design team. Geotechnical engineers are not building-envelope or mold specialists.
Copyright 2019 by Geoprofessional Business Association (GBA). Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with GBA’s specific written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of
GBA, and only for purposes of scholarly research or book review. Only members of GBA may use this document or its wording as a complement to or as an element of a report of any kind. Any other firm, individual, or other entity that so uses this document without being a GBA member could be committing negligent or intentional (fraudulent) misrepresentation.
Telephone: 301/565-2733
e-mail: info@geoprofessional.org www.geoprofessional.org
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
February 21, 2024
ES-9583
Lake Samish, LLC
7710 – 203rd Street Southeast
Snohomish, Washington 98296
Attention: Dan Peck
Dear Dan:
Earth Solutions NW, LLC (ESNW) is pleased to present this report titled “Geotechnical
Engineering Study, Proposed Bales Place Short Plat, 11806 – Southeast 192nd Street, Renton,
Washington”. Based on the results of the study, the proposed project is feasible from a
geotechnical standpoint. The study indicates the site is underlain primarily by near-surface fill
and competent glacial till. Light to moderate groundwater seepage was exposed at all test pit
locations during the January 2024 exploration.
We understand the site will be graded to create an access driveway and building pads. New
structural fill should be placed on competent native soil. Areas of existing fill will need to be
removed or reworked to establish suitable bearing conditions in proposed structural areas, as
recommended by ESNW at the time of construction. If earthwork activities occur during wet
weather, additional drainage measures, cement treatment of native soil, and the use of select fill
material will likely be necessary. After completing earthwork activities in accordance with
recommendations in this report, the proposed structures can be supported on conventional
spread and continuous foundations bearing on undisturbed, competent native soil, compacted
native soil, or new structural fill. If structural building pads are disturbed during wet weather,
remediation measures such as cement treatment or overexcavation and replacement with rock
may be necessary in some areas.
In our opinion, the native glacial till deposits should be considered unsuitable for infiltration
purposes from a geotechnical standpoint, given the appreciable fines contents and dense in-situ
condition. Further discussion of infiltration feasibility is provided within this report.
Pertinent geotechnical recommendations are provided in this study. We appreciate the
opportunity to be of service to you on this project. If you have any questions regarding the content
of this geotechnical engineering study, please call.
Sincerely,
EARTH SOLUTIONS NW, LLC
John M. Neer, G.I.T.
Staff Geologist
15365 NE 90th Street, Suite 100 • Redmond, WA 98052 •(425) 449-4704
3130 Varney Lane, Suite 105 •Pasco, WA 99301 •(509) 905-0275
esnw.com
Earth Solutions NW LLC
Geotechnical Engineering, Construction
Observation/Testing and Environmental Services
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
Earth Solutions NW, LLC
Table of Contents
ES-9583
PAGE
INTRODUCTION ................................................................................. 1
General .................................................................................... 1
Project Description ................................................................. 1
SITE CONDITIONS ............................................................................. 2
Surface ..................................................................................... 2
Subsurface .............................................................................. 2
Topsoil and Fill ............................................................. 2
Native Soil ..................................................................... 3
Geologic Setting ........................................................... 3
Groundwater ................................................................. 3
Geologically Hazardous Areas Assessment ........................ 3
DISCUSSION AND RECOMMENDATIONS ....................................... 4
General .................................................................................... 4
Site Preparation and Earthwork ............................................. 4
Temporary Erosion Control ......................................... 5
Stripping ....................................................................... 5
Topsoil and Organic Material Removal and
Replacement ................................................................. 6
In-situ and Imported Soils ........................................... 6
Structural Fill ................................................................ 7
Wet-Season Grading .................................................... 7
Excavations and Slopes .............................................. 8
Foundations ............................................................................ 8
Seismic Design ....................................................................... 9
Liquefaction .................................................................. 9
Slab-on-Grade Floors ............................................................. 10
Retaining Walls ....................................................................... 10
Drainage................................................................................... 11
Infiltration Evaluation ................................................... 11
Utility Support and Trench Backfill ....................................... 11
Preliminary Pavement Sections ............................................. 12
LIMITATIONS ...................................................................................... 13
Additional Services ................................................................. 13
REFERENCES .................................................................................... 13
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
Earth Solutions NW, LLC
Table of Contents
Cont’d
ES-9583
GRAPHICS
Plate 1 Vicinity Map
Plate 2 Test Pit Location Plan
Plate 3 Retaining Wall Drainage Detail
Plate 4 Footing Drain Detail
APPENDICES
Appendix A Subsurface Exploration Logs
Appendix B Laboratory Test Results
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
Earth Solutions NW, LLC
GEOTECHNICAL ENGINEERING STUDY
PROPOSED BALES PLACE SHORT PLAT
11806 SOUTHEAST 192ND STREET
RENTON, WASHINGTON
ES-9583
INTRODUCTION
General
This geotechnical engineering study was prepared for the proposed residential development to
be constructed at 11806 – Southeast 192nd Street in Renton, Washington. To complete this
study, we performed the following:
Subsurface exploration to characterize soil and groundwater conditions.
Laboratory testing of soil samples collected at the test pit locations.
Engineering analyses.
Preparation of this report.
Project Description
Based on our understanding of project objectives, the site will be redeveloped with several new
single-family residential lots and associated improvements. Access to the plat will be provided
by Southeast 192nd Street.
Grading plans were not available at the time this report was prepared; however, we anticipate
grading activities will include cuts and fills of up to about four feet to establish building pad and
roadway alignments.
Based on our experience with similar projects, the proposed residential structures will likely be
two to three stories in height and constructed utilizing relatively lightly loaded wood framing
supported on conventional foundations. We anticipate perimeter footing loads of 1 to 2 kips per
linear foot, isolated footing loads of less than 20 kips, and 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.
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February 21, 2024 Page 2
Earth Solutions NW, LLC
SITE CONDITIONS
Surface
The subject site is located at 11806 Southeast 192nd Street in Renton, Washington, as illustrated
on the Vicinity Map (Plate 1). The site consists of one residential tax parcel (King County parcel
number 6198400360) totaling approximately 2.25 acres of land. The site is currently developed
with a single-family residence, a cell tower and service building, and associated improvements.
The site vegetation primarily consists of grass landscaping areas with sporadic trees along the
perimeter. The site topography gently descends from north-northwest to south-southeast with
approximately six feet of elevation change occurring within property boundaries.
Subsurface
An ESNW representative observed, logged, and sampled five test pits on January 26, 2024. The
test pits were excavated within accessible portions of the property using a trackhoe and operator
provided by the client. The test pits were completed to evaluate and classify soil and groundwater
conditions within the proposed development area. The maximum exploration depth was
approximately nine feet below the existing ground surface (bgs), and all explorations were
terminated in undisturbed native soil. The approximate locations of the test pits are depicted on
Plate 2 (Test Pit Location Plan). Please refer to the test pit logs provided in Appendix A for a
more detailed description of subsurface conditions. Representative soil samples collected at the
test pit locations were evaluated in general accordance with Unified Soil Classification System
(USCS) and United States Department of Agriculture (USDA) methods and procedures.
Topsoil and Fill
Topsoil was observed within the upper 4 to 6 inches of existing grades at two test pit locations
(TP-1 and TP-3). The topsoil was characterized by its dark brown color, the presence of fine
organic material, and small root intrusions.
We encountered fill at all test pit locations extending between the existing ground surface and
two feet bgs. The fill was generally characterized as silty sand with and without gravel (USCS:
SM) in a moist to wet condition. The relative density of the fill was generally loose. Minor amounts
of plastic debris were observed within the fill at one test pit location (TP-1).
Underlying the fill, relic topsoil horizons were encountered beginning at depths of roughly 1.5 to
2.0 feet bgs and were on the order of 12 to 18 inches in thickness. The relic topsoil was
characterized by its dark brown color, the presence of fine organic material, and small root
intrusions.
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Earth Solutions NW, LLC
Native Soil
Underlying the topsoil and fill, native soil consisting primarily of silty sand (USCS: SM) was
encountered, and characterized primarily as glacial till deposits. Native soil relative density
generally increased with depth and became dense and weakly cemented beginning at depths of
roughly two-and-one-half feet to three-and-one-half feet bgs. The native soil was generally
encountered in a moist to wet condition.
Geologic Setting
The referenced geologic map identifies ground moraine deposits (Qgt), otherwise known as
glacial till, across the subject site. As described on the geologic map, ground moraine deposits
are characterized as ablation till over thick sections of lodgment till. Glacial till is typically
comprised of unsorted cobbles, pebbly sand, and sandy silt, with a compact layer (referred to as
“hardpan”) at depth.
The referenced Web Soil Survey (WSS) identifies Alderwood gravelly sandy loam (Map Unit:
AgB) as the primary soil unit underlying the site and surrounding areas. The Alderwood series
was formed in ridges and hills and is derived from glacial drift and/or glacial outwash over dense
glaciomarine deposits.
Based on the subsurface observations, the native soil is generally consistent with glacial till
deposits and Alderwood series soil.
Groundwater
Perched groundwater seepage was observed at all test pit locations during the January 2024
fieldwork. Light to moderate seepage was observed at depths between two to three-and-one-
half feet. Groundwater seepage rates and elevations fluctuate depending on many factors,
including precipitation duration and intensity, the time of year, and soil conditions. Groundwater
seepage flow rates are typically higher during the winter, spring, and early summer months.
Therefore, perched groundwater seepage should be expected in site excavations, particularly if
excavations are made in winter, spring, and early summer months.
Geologically Hazardous Areas Assessment
As part of the geologically hazardous areas assessment, we reviewed the City of Renton (COR)
interactive map and Chapter 4-3 of the Renton Municipal Code (RMC), which focuses on
designations, definitions, and regulations of geologically hazardous areas. RMC 4-3-050
classifies geologically hazardous areas as those areas susceptible to damage relating to
sensitive and protected slopes, landslides, erosion, seismic activity, and coal mines. Based on
our review, the subject site is not mapped within, or adjacent to, any geologically hazardous
areas. Based on the fieldwork performed at the subject site and our site-specific observations, it
is our opinion the site is not within, or adjacent to, any geologically hazardous areas recognized
by the RMC.
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Earth Solutions NW, LLC
DISCUSSION AND RECOMMENDATIONS
General
Based on the investigation, construction of the proposed residential development is feasible from
a geotechnical standpoint. The primary geotechnical considerations for the proposal are
associated with structural fill placement and compaction, utility trench support and backfill,
drainage, and foundation support.
The site will be graded to create an access driveway and building pads. New structural fill should
be placed on competent native soil. Areas of existing fill will need to be removed or reworked to
establish suitable bearing conditions in proposed structural areas, as recommended by ESNW at
the time of construction. If earthwork activities occur during wet weather, additional drainage
measures, cement treatment of native soil, and the use of select fill material will likely be
necessary. After completing earthwork activities in accordance with recommendations in this
report, the proposed structures can be supported on conventional spread and continuous
foundations bearing on undisturbed, competent native soil, compacted native soil, or new
structural fill. If structural building pads are disturbed during wet weather, remediation measures
such as cement treatment or overexcavation and replacement with rock may be necessary in
some areas.
Site Preparation and Earthwork
Initial site preparation activities will consist of installing temporary erosion control measures,
establishing grading limits, and performing clearing and site stripping. Subsequent earthwork
activities will involve mass site grading and related infrastructure improvements. If earthwork
activities occur during wet weather, additional drainage measures, cement treatment of native
soil (where allowed by the presiding jurisdiction), and the use of select fill material will likely be
necessary during construction.
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Earth Solutions NW, LLC
Temporary Erosion Control
The following temporary erosion control measures should be considered:
Temporary construction entrances and drive lanes, consisting of at least six inches of
quarry spalls, should be considered to both minimize off-site soil tracking and provide a
stable access entrance surface. Placing geotextile fabric underneath the quarry spalls will
provide greater stability if needed.
Silt fencing should be placed around the site perimeter.
When not in use, soil stockpiles should be covered or otherwise protected to reduce the
potential for soil erosion, especially during periods of wet weather.
Temporary measures for controlling surface water runoff, such as interceptor trenches,
sumps, or interceptor swales, should be installed prior to beginning earthwork activities.
Dry soils disturbed during construction should be wetted to minimize dust and airborne soil
erosion.
When appropriate, permanent planting or hydroseeding will help to stabilize site soils.
Additional TESC BMPs, as specified by the project civil engineer and indicated on the plans
and/or as required by the permitting jurisdiction, should be incorporated into construction
activities. Temporary erosion control measures may be modified during construction as site
conditions require and as recommended by the site erosion control lead.
Stripping
Topsoil was encountered generally within the upper four to six inches of existing grades at two of
the test pit locations. As such, the upper topsoil should be stripped prior to reworking the
underlying existing fill and placing new structural fill.
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Earth Solutions NW, LLC
Topsoil and Organic Material Removal and Replacement
Relic topsoil layers were observed underlying the fill and ranged in thickness between roughly
one and one-half to two feet. The following is recommended for topsoil and organic material
removal and replacement in structural areas:
Remove upper existing fill soil, segregate from organic and deleterious material, stockpile
and protect from moisture.
Remove topsoil and organic material.
If moderate to heavy groundwater is present following removal, place a layer of quarry
spalls and cover with filter fabric to establish a stable surface.
Begin mass grading with structural fill, utilizing the stockpiled existing fill if deemed
suitable.
In-situ and Imported Soils
Based on the conditions observed during the subsurface exploration, the on-site soil is highly
moisture sensitive. Successful use of the on-site soil as structural fill will largely be dictated by
the moisture content at the time of placement and compaction. Given the limited site area, on-
site remediation efforts (such as aeration) may not be practicable. If the on-site soil cannot be
successfully compacted, the use of an imported soil may be necessary. In our opinion, a
contingency should be provided in the project budget for export of soil that cannot be successfully
compacted as structural fill, particularly if structural backfill take place during periods of extended
rainfall activity. In general, soils with fines contents greater than 5 percent typically degrade
rapidly when exposed to periods of rainfall.
Imported structural fill should consist of a well-graded, granular soil that is capable of achieving
a suitable working moisture content. During wet weather conditions, imported soil intended for
use as structural fill should consist of a well-graded, granular soil with 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).
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Earth Solutions NW, LLC
Structural Fill
Structural fill placed and compacted during site grading activities should meet the following
specifications and guidelines:
Structural fill material Granular soil
Moisture content At or slightly above optimum
Relative compaction (minimum) 95 percent (Modified Proctor)
Loose lift thickness (maximum) 12 inches
The existing soil may not be suitable for use as structural fill unless the material is at (or slightly
above) the optimum moisture content at the time of placement of and compaction. Soil shall not
be placed dry of the optimum moisture content and should be evaluated by ESNW during
construction. A minimum relative compaction of 90 percent may be feasible for certain areas of
mass grading from a geotechnical standpoint but should be evaluated by ESNW at the time of
construction and confirmed with the permitting jurisdiction.
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.
Wet-Season Grading
If earthwork activities occur during wet weather, additional drainage measures, cement treatment
of native soil (if approved by the presiding jurisdiction), and/or the use of select fill material will
likely be necessary. Additionally, measures to protect structural subgrades should be considered
if exposed during wet weather. Site-specific recommendations can be provided at the time of
construction and may include leaving cut areas several inches above design subgrade elevations,
covering working surfaces with crushed rock, protecting structural fill soil from adverse moisture
conditions, and additional TESC recommendations. ESNW can assist in obtaining a wet-season
grading permit if required by the governing jurisdiction.
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Lake Samish, LLC ES-9583
February 21, 2024 Page 8
Earth Solutions NW, LLC
Excavations and Slopes
Based on the soil conditions observed at the test pit locations, the following allowable temporary
slope inclinations, as a function of horizontal to vertical (H:V) inclination, may be used. The
applicable Federal Occupation Safety and Health Administration and Washington Industrial
Safety and Health Act soil classifications are also provided:
Areas exposing groundwater seepage 1.5H:1V (Type C)
Loose soil 1.5H:1V (Type C)
Medium dense soil 1H:1V (Type B)
Dense to very dense, cemented native soil 0.75H:1V (Type A)
The presence of groundwater may cause sloughing of temporary slopes. An ESNW
representative should observe temporary and permanent slopes to confirm the slope inclinations
are suitable for the exposed soil conditions and to provide additional excavation and slope
recommendations, as necessary. If the recommended temporary slope inclinations cannot be
achieved, temporary shoring may be necessary to support excavations. Permanent slopes
should be planted with vegetation to enhance stability and to minimize erosion and should
maintain a gradient of 2H:1V or flatter.
Foundations
The proposed residential structures can be supported on conventional spread and continuous
footings bearing on undisturbed, competent native soil, compacted native soil, or new structural
fill. Provided site earthwork activities are completed in accordance with our recommendations,
suitable soil conditions should be exposed in building pad structural subgrade areas. Due to the
high moisture sensitivity of the site soil, foundation subgrade areas should be protected from wet
weather or areas of remediation should be anticipated; a layer of crushed rock can be considered
to protect foundation subgrade areas. If structural building pads are disturbed during wet
weather, remediation measures such as cement treatment or overexcavation and replacement
with rock may be necessary in some areas.
Provided the structures 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
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
Lake Samish, LLC ES-9583
February 21, 2024 Page 9
Earth Solutions NW, LLC
A one-third increase in the allowable soil bearing capacity may be assumed for short-term wind
and seismic loading conditions. The above passive earth pressure and coefficient of friction
values include a factor-of-safety of 1.5. With structural loading as expected, total settlement in
the range of one inch and differential settlement of about one-half inch is anticipated. Most
settlement should occur during construction when dead loads are applied.
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 pit locations, the parameters and values provided below are recommended for seismic
design per the 2018 IBC.
Parameter Value
Site Class C*
Mapped short period spectral response acceleration, SS (g) 1.365
Mapped 1-second period spectral response acceleration, S1 (g) 0.465
Short period site coefficient, Fa 1.2
Long period site coefficient, Fv 1.5
Adjusted short period spectral response acceleration, SMS (g) 1.638
Adjusted 1-second period spectral response acceleration, SM1 (g) 0.698
Design short period spectral response acceleration, SDS (g) 1.092
Design 1-second period spectral response acceleration, SD1 (g) 0.465
* Assumes very dense native soil conditions, encountered to a maximum depth of nine feet bgs during the January
2024 field exploration, remain very dense to at least 100 feet bgs.
Liquefaction
The referenced liquefaction susceptibility map indicates the subject site maintains very low
liquefaction susceptibility. Liquefaction is a phenomenon where saturated, loose, and
cohesionless sand or silt 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 negligible. The composition and relatively dense characteristics of the native soil
were the primary bases for this opinion.
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Earth Solutions NW, LLC
Slab-on-Grade Floors
Slab-on-grade floors for the proposed residential structures should be supported on well-
compacted, firm, and unyielding subgrades. Where feasible, the native soil exposed at the slab-
on-grade subgrade levels can likely be compacted in situ to the specifications of structural fill if
groundwater seepage does not interfere with compaction activities. Unstable or yielding
subgrade areas should be recompacted or overexcavated and replaced with suitable structural
fill prior to slab construction.
A capillary break consisting of at least four inches of free-draining crushed rock or gravel should
be placed below the slabs. 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 vapor barriers below the slabs should be considered. If a vapor barrier is to be utilized, it
should be a material specifically intended for use as a vapor barrier and should be installed per
the specifications of the manufacturer.
Retaining Walls
Retaining walls must be designed to resist earth pressures and applicable surcharge loads. The
following parameters may be used for design:
Active earth pressure (unrestrained condition) 35 pcf (equivalent fluid)
At-rest earth pressure (restrained condition) 55 pcf
Traffic surcharge (passenger vehicles) 70 psf (rectangular distribution)*
Passive earth pressure 300 pcf (equivalent fluid)
Coefficient of friction 0.40
Seismic surcharge 8H psf**
* Where applicable.
** Where H equals the retained height (in feet).
The passive earth pressure and coefficient of friction values include a safety factor of 1.5. The
above design parameters are based on a level backfill condition and level grade at the wall toe.
Revised design values will be necessary if sloping grades are to be used above or below retaining
walls. Additional surcharge loading from adjacent foundations, sloped backfill, or other relevant
loads should be included in the retaining wall design.
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
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Earth Solutions NW, LLC
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. 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.
Drainage
Groundwater seepage should be anticipated in site excavations depending on the time of year
grading operations take place, particularly within excavations for utilities. Temporary measures
to control surface water runoff and groundwater during construction would likely involve
interceptor trenches, interceptor swales, and sumps. ESNW should be consulted during
preliminary grading to both identify areas of seepage and provide recommendations to reduce
the potential for seepage-related instability.
Finish grades must be designed to direct surface drain water away from the structures and slopes.
Water must not be allowed to pond adjacent to the structures or slopes. Grades adjacent to the
structures should be sloped away at a gradient of either at least 2 percent for a horizontal distance
of 10 feet or the maximum allowed by adjacent structures. In our opinion, foundation drains
should be installed along building perimeter footings. A typical foundation drain detail is provided
on Plate 4.
Infiltration Evaluation
As indicated in the Subsurface section of this report, the native soil encountered during our
fieldwork was primarily characterized as glacial till and becomes weakly cemented and dense
(hardpan) at depths of about two-and-one-half feet to three-and-one-half feet bgs. A small-scale
Pilot Infiltration Test (PIT) was completed in general accordance with the 2022 City of Renton
Surface Water Design Manual. The PIT was conducted at a depth of six and one-half feet bgs
at test pit location TP-2 in native soil. Following the necessary soaking period, no measurable
infiltration was observed at the test location.
From a geotechnical standpoint, infiltration on the subject site should be considered infeasible
based on the shallow depth to relatively impermeable native soils.
Utility Support and Trench Backfill
The native soil should generally be suitable for utility support. However, remedial measures may
be necessary in some areas to provide support for utilities, such as overexcavation and
replacement with structural fill and/or placement of geotextile fabric. Groundwater may be
encountered within utility excavations, and caving of trench walls may occur where groundwater
is encountered.
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
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February 21, 2024 Page 12
Earth Solutions NW, LLC
The on-site soil may not be suitable for use as structural backfill throughout utility trench
excavations unless the soil is at (or slightly above) the optimum moisture content at the time of
placement and compaction. If utility installation occurs during the wet season, site soils will likely
be saturated and therefore difficult to use as utility backfill without treatment or aeration. Each
section of the utility lines must be adequately supported in the bedding material. Utility trench
backfill should be placed and compacted to the specifications of structural fill, as previously
detailed in this report, or to the applicable specifications of the presiding jurisdiction.
Preliminary Pavement Sections
The performance of site pavements is largely related to the condition of the underlying subgrade.
To ensure adequate pavement performance, the subgrade should be in a firm and unyielding
condition when subjected to proofrolling with a loaded dump truck. Structural fill in pavement
areas should be compacted to the specifications previously detailed in this report. Soft, wet, or
otherwise unsuitable subgrade areas may still exist after base grading activities. Areas
containing unsuitable or yielding subgrade conditions will require remedial measures, such as
overexcavation and replacement with crushed rock or structural fill, prior to pavement.
For lightly loaded pavement areas subjected primarily to passenger vehicles, the following
preliminary pavement sections may be considered:
A minimum of two inches of hot-mix asphalt (HMA) placed over four inches of crushed
rock base (CRB).
A minimum of two inches of HMA placed over three inches of asphalt-treated base (ATB).
For relatively high volume, heavily loaded pavements areas subjected to occasional truck traffic,
the following preliminary pavement sections may be considered:
A minimum of three inches of HMA placed over six inches of CRB.
A minimum of three inches of HMA placed over four and one-half inches of ATB.
A representative of ESNW should be requested to observe subgrade conditions prior to
placement of CRB or ATB. As necessary, supplemental recommendations for achieving
subgrade stability and drainage can be provided. If on-site roads will be constructed with an
inverted crown, additional drainage measures may be recommended to assist in maintaining road
subgrade and pavement stability.
Final pavement design recommendations, including recommendations for heavy traffic areas,
access roads, and frontage improvement areas, can be provided once final traffic loading has
been determined. Road standards utilized by the governing jurisdiction may supersede the
recommendations provided in this report. The HMA, ATB, and CRB materials should conform to
WSDOT specifications. All soil base material should be compacted to a relative compaction of
95 percent, based on the laboratory maximum dry density as determined by ASTM D1557.
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
Lake Samish, LLC ES-9583
February 21, 2024 Page 13
Earth Solutions NW, LLC
LIMITATIONS
This geotechnical evaluation report has been prepared for the exclusive use of Lake Samish,
LLC and its representatives. The recommendations and conclusions provided in this
geotechnical engineering study 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 locations may exist, and may not become evident until
construction. ESNW should reevaluate the conclusions in this geotechnical engineering study if
variations are encountered.
Additional Services
ESNW should have an opportunity to review the final design with respect to the geotechnical
recommendations provided in this report. ESNW should also be retained to provide testing and
consultation services during construction.
REFERENCES
The following documents and resources were reviewed as part of the report preparation:
Geologic map of the Renton quadrangle, King County, Washington, prepared by D.R.
Mullineaux, dated 1965
WSS, maintained by the Natural Resources Conservation Service under the USDA
RMC Chapter 4-3-050 – Critical Areas Regulations
2022 City of Renton Surface Water Design Manual, prepared by City of Renton
Liquefaction Susceptibility Map, dated May 2010, prepared by King County
COR Maps (City of Renton GIS database)
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
Geotechnical Engineering,Construction
Observation/Testing and Environmental Services
Drawn MRS
Checked JMN Date Feb.2024
Date 02/19/2024 Proj.No.9583
Plate 1
Earth Solutions NWLLCEarthSolutionsNWLLC
EarthSolutionsNWLLC
Vicinity Map
Bales Place Short Plat
Renton,Washington
Reference:
King County,Washington
OpenStreetMap.org
NORTH
NOTE:This plate may contain areas of color.ESNW cannot be
responsible for any subsequent misinterpretation of the information
resulting from black &white reproductions of this plate.
SITE
Renton
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
Drawn MRS
Checked JMN Date Feb.2024
Date 02/19/2024 Proj.No.9583
Plate 2
Geotechnical Engineering,Construction
Observation/Testing and Environmental Services
Earth Solutions NWLLCEarthSolutionsNWLLC
EarthSolutionsNWLLC
Test Pit Location Plan
Bales Place Short Plat
Renton,Washington
NORTH
NOTE:This plate may contain areas of color.ESNW cannot be
responsible for any subsequent misinterpretation of the information
resulting from black &white reproductions of this plate.
NOTE:The graphics shown on this plate are not intended for design
purposes or precise scale measurements,but only to illustrate the
approximate test locations relative to the approximate locations of
existing and /or proposed site features.The information illustrated
is largely based on data provided by the client at the time of our
study.ESNW cannot be responsible for subsequent design changes
or interpretation of the data by others.
LEGEND
Approximate Location of
ESNW Test Pit,Proj.No.
ES-9583,Jan.2024
Subject Site
Existing Building
0 50 100 200
Scale in Feet1"=100'
TP-1
TP-1 TP-2
TP-3
TP-4
TP-5
S.E.192ND STREET
116TH AVENUE S.E.
506
500
506
500
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
Geotechnical Engineering,Construction
Observation/Testing and Environmental Services
Drawn MRS
Checked JMN Date Feb.2024
Date 02/19/2024 Proj.No.9583
Plate 3
Earth Solutions NWLLCEarthSolutionsNWLLC
EarthSolutionsNWLLC
NOTES:
Free-draining Backfill should consist
of soil having less than 5 percent fines.
Percent passing No.4 sieve should be
25 to 75 percent.
Sheet Drain may be feasible in lieu
of Free-draining Backfill,per ESNW
recommendations.
Drain Pipe should consist of perforated,
rigid PVC Pipe surrounded with 1-inch
Drain Rock.
LEGEND:
Free-draining Structural Backfill
1-inch Drain Rock
18"Min.
Structural
Fill
Perforated Rigid Drain Pipe
(Surround in Drain Rock)
SCHEMATIC ONLY -NOT TO SCALE
NOT A CONSTRUCTION DRAWING
Retaining Wall Drainage Detail
Bales Place Short Plat
Renton,Washington
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
Geotechnical Engineering,Construction
Observation/Testing and Environmental Services
Drawn MRS
Checked JMN Date Feb.2024
Date 02/19/2024 Proj.No.9583
Plate 4
Earth Solutions NWLLCEarthSolutionsNWLLC
EarthSolutionsNWLLC
Slope
Perforated Rigid Drain Pipe
(Surround in Drain Rock)
18"Min.
NOTES:
Do NOT tie roof downspouts
to Footing Drain.
Surface Seal to consist of
12"of less permeable,suitable
soil.Slope away from building.
LEGEND:
Surface Seal:native soil or
other low-permeability material.
1-inch Drain Rock
SCHEMATIC ONLY -NOT TO SCALE
NOT A CONSTRUCTION DRAWING
Footing Drain Detail
Bales Place Short Plat
Renton,Washington
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
Earth Solutions NW, LLC
Appendix A
Subsurface Exploration Logs
ES-9583
The subsurface conditions at the site were explored on January 26, 2024, by excavating five test
pits using a mini-trackhoe and operator provided by the client. The approximate locations of the
test pits are illustrated on Plate 2 of this study. The test pit logs are provided in this Appendix.
The test pits were advanced to a maximum depth of approximately nine feet bgs.
The final logs represent the interpretations of the field logs and the results of laboratory analyses.
The stratification lines on the logs represent the approximate boundaries between soil types. In
actuality, the transitions may be more gradual.
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
>
12%
Fines
<
5%
Fines
Highly
Organic
Soils
Silts
and
Clays
Liquid
Limit
50
or
More
Silts
and
Clays
Liquid
Limit
Less
Than
50
Fine-Grained
Soils
-
50%
or
More
Passes
No.
200
Sieve
Coarse-Grained
Soils
-
More
Than
50%
Retained
on
No.
200
Sieve
Sands
-
50%
or
More
of
Coarse
Fraction
Passes
No.
4
Sieve
Gravels
-
More
Than
50%
of
Coarse
Fraction
Retained
on
No.
4
Sieve
>
12%
Fines
<
5%
Fines GW
GP
GM
GC
SW
SP
SM
SC
ML
CL
OL
MH
CH
OH
PT
Well-graded gravel with
or without sand,little to
no fines
Poorly graded gravel with
or without sand,little to
no fines
Silty gravel with or without
sand
Clayey gravel with or
without sand
Well-graded sand with
or without gravel,little to
no fines
Poorly graded sand with
or without gravel,little to
no fines
Silty sand with or without
gravel
Clayey sand with or
without gravel
Silt with or without sand
or gravel;sandy or
gravelly silt
Clay of low to medium
plasticity;lean clay with
or without sand or gravel;
sandy or gravelly lean clay
Organic clay or silt of
low plasticity
Elastic silt with or withoutsandorgravel;sandy or
gravelly elastic silt
Clay of high plasticity;
fat clay with or without
sand or gravel;sandy or
gravelly fat clay
Organic clay or silt of
medium to high plasticity
Peat,muck,and other
highly organic soils
EEaarrtthh SSoolluuttiioonnss NNWWLLC
Geotechnical Engineering,ConstructionObservation/Testing and Environmental Services EXPLORATION LOG KEY
Fill FILL Made Ground
Classifications of soils in this geotechnical report and as shown on the exploration logs are based on visualfieldand/or laboratory observations,which include density/consistency,moisture condition,grain size,andplasticityestimates,and should not be construed to imply field or laboratory testing unless presented herein.
Visual-manual and/or laboratory classification methods of ASTM D2487 and D2488 were used as an
identification guide for the Unified Soil Classification System.
Terms Describing Relative Density and Consistency
Coarse-Grained Soils:
Fine-Grained Soils:
SPT blows/foot
SPT blows/foot
Test Symbols &Units
Fines =Fines Content (%)
MC =Moisture Content (%)
DD =Dry Density (pcf)
Str =Shear Strength (tsf)
PID =Photoionization Detector (ppm)
OC =Organic Content (%)
CEC =Cation Exchange Capacity (meq/100 g)
LL =Liquid Limit (%)
PL =Plastic Limit (%)
PI =Plasticity Index (%)
Component Definitions
Descriptive Term Size Range and Sieve Number
Smaller than No.200 (0.075 mm)
Boulders
Modifier Definitions
Percentage by
Weight (Approx.)
<5
5 to 14
15 to 29
>30_
Modifier
Trace (sand,silt,clay,gravel)
Slightly (sandy,silty,clayey,gravelly)
Sandy,silty,clayey,gravelly
Very (sandy,silty,clayey,gravelly)
Moisture Content
Dry -Absence of moisture,dusty,dry to
the touch
Damp -Perceptible moisture,likely below
optimum MC
Moist -Damp but no visible water,likely
at/near optimum MC
Wet -Water visible but not free draining,
likely above optimum MC
Saturated/Water Bearing -Visible free
water,typically below groundwater table
Symbols
Cement groutsurfaceseal
Bentonite
chips
Grout
seal
Filter pack with
blank casing
section
Screened casing
or Hydrotip with
filter pack
End cap
ATD =At time
of drilling
Static water
level (date)
_>50
Density
Very Loose
Loose
Medium Dense
Dense
Very Dense
Consistency
Very Soft
Soft
Medium Stiff
Stiff
Very Stiff
Hard
<4
4 to 9
10 to 29
30 to 49
<2
2 to 3
4 to 7
8 to 14
15 to 29
_>30
LLC
EarthSolutionsNWLLC
Cobbles
GravelCoarse GravelFineGravel
Sand
Coarse Sand
Medium Sand
Fine Sand
Silt and Clay
Larger than 12"
3"to 12"
3"to No.4 (4.75 mm)3"to 3/4"3/4"to No.4 (4.75 mm)
No.4 (4.75 mm)to No.200 (0.075 mm)
No.4 (4.75 mm)to No.10 (2.00 mm)
No.10 (2.00 mm)to No.40 (0.425 mm)
No.40 (0.425 mm)to No.200 (0.075 mm)
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
498.5
497.0
495.5
491.0
GB
GB
GB
GB
MC = 18.7
MC = 16.0
MC = 19.9
MC = 18.7
TPSL
SM
TPSL
SM
Dark brown TOPSOIL (Fill)
Brown silty SAND, loose, wet (Fill)
-probed 12"
-plastic debris
Dark brown TOPSOIL with roots
-probed 8"
-moderate groundwater seepage
Gray silty SAND, dense, moist to wet
-mottling to 6.5', weakly cemented
-probed 2"
-becomes very dense
-elevated moisture content due to seepage entering test pit above
Test pit terminated at 8.0 feet below existing grade. Groundwater seepage encountered at3.0 feet during excavation. No caving observed.
LIMITATIONS: Ground elevation (if listed) is approximate; the test location was notsurveyed. 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 acomplete understanding of subsurface conditions.
0.5
2.0
3.5
8.0
SA
M
P
L
E
T
Y
P
E
NU
M
B
E
R
DE
P
T
H
(f
t
)
0.0
2.5
5.0
7.5
PAGE 1 OF 1
TEST PIT NUMBER TP-1
CHECKED BY HTW
NOTES
SURFACE CONDITIONS Grass
AT TIME OF EXCAVATIONAT TIME OF EXCAVATION
AFTER EXCAVATION
EXCAVATION CONTRACTOR Client Provided
DATE STARTED 1/26/24 COMPLETED 1/26/24
GROUND WATER LEVEL:
GROUND ELEVATION 499 ft
LOGGED BY JMN
LATITUDE 47.43043 LONGITUDE -122.18297
PROJECT NUMBER ES-9583 PROJECT NAME Bales Place Short Plat
GE
N
E
R
A
L
B
H
/
T
P
/
W
E
L
L
-
9
5
8
3
.
G
P
J
-
G
I
N
T
U
S
.
G
D
T
-
2
/
2
1
/
2
4
15365 NE 90th Street, Suite 100
Redmond, WA 98052
Office (425) 449-4704 | esnw.com
Branch Office: Pasco, WA
TESTS
U.
S
.
C
.
S
.
MATERIAL DESCRIPTION
GR
A
P
H
I
C
LO
G
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
497.0
495.5
492.0
GB
GB
GB
MC = 82.5
MC = 12.5
Fines = 34.5
MC = 20.6Fines = 29.3
SM
TPSL
SM
Brown silty SAND, loose, wet (Fill)
-probed 12"
-moderate groundwater seepage at 2'
Dark brown TOPSOIL with roots
-elevated moisture content due to seepage entering test pit above
-probed 2"
Gray silty SAND, dense, moist
-light groundwater seepage
-mottling to 6', weakly cemented[USDA Classification: gravelly sandy LOAM]
-elevated moisture content due to seepage entering test pit above
[USDA Classification: slightly gravelly sandy LOAM]
Test pit terminated at 7.0 feet below existing grade. Groundwater seepage encountered at2.0 and 3.5 feet during excavation. No caving observed.
LIMITATIONS: Ground elevation (if listed) is approximate; the test location was notsurveyed. 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 acomplete understanding of subsurface conditions.
2.0
3.5
7.0
SA
M
P
L
E
T
Y
P
E
NU
M
B
E
R
DE
P
T
H
(f
t
)
0.0
2.5
5.0
PAGE 1 OF 1
TEST PIT NUMBER TP-2
CHECKED BY HTW
NOTES
SURFACE CONDITIONS Grass
AT TIME OF EXCAVATIONAT TIME OF EXCAVATION
AFTER EXCAVATION
EXCAVATION CONTRACTOR Client Provided
DATE STARTED 1/26/24 COMPLETED 1/26/24
GROUND WATER LEVEL:
GROUND ELEVATION 499 ft
LOGGED BY JMN
LATITUDE 47.43042 LONGITUDE -122.18274
PROJECT NUMBER ES-9583 PROJECT NAME Bales Place Short Plat
GE
N
E
R
A
L
B
H
/
T
P
/
W
E
L
L
-
9
5
8
3
.
G
P
J
-
G
I
N
T
U
S
.
G
D
T
-
2
/
2
1
/
2
4
15365 NE 90th Street, Suite 100
Redmond, WA 98052
Office (425) 449-4704 | esnw.com
Branch Office: Pasco, WA
TESTS
U.
S
.
C
.
S
.
MATERIAL DESCRIPTION
GR
A
P
H
I
C
LO
G
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
504.5
503.5
502.5
496.5
GB
GB
GB
GB
MC = 44.9
MC = 20.2
Fines = 34.1
MC = 13.9
MC = 15.2
TPSL
SM
TPSL
SM
Dark brown TOPSOIL with roots (Fill)
Brown silty SAND with gravel, loose, wet (Fill)
-probed 12"
Dark brown TOPSOIL
-moderate groundwater seepage at 2.5'
Gray silty SAND, dense, moist to wet
-mottling to 6', weakly cemented
-probed 2"
[USDA Classification: slightly gravelly sandy LOAM]
-elevated moisture content due to seepage entering test pit above
-becomes very dense
Test pit terminated at 8.5 feet below existing grade. Groundwater seepage encountered at
2.5 feet 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 onthis test log as a standalone document. Refer to the text of the geotechnical report for acomplete understanding of subsurface conditions.
0.5
1.5
2.5
8.5
SA
M
P
L
E
T
Y
P
E
NU
M
B
E
R
DE
P
T
H
(f
t
)
0.0
2.5
5.0
7.5
PAGE 1 OF 1
TEST PIT NUMBER TP-3
CHECKED BY HTW
NOTES
SURFACE CONDITIONS Grass
AT TIME OF EXCAVATIONAT TIME OF EXCAVATION
AFTER EXCAVATION
EXCAVATION CONTRACTOR Client Provided
DATE STARTED 1/26/24 COMPLETED 1/26/24
GROUND WATER LEVEL:
GROUND ELEVATION 505 ft
LOGGED BY JMN
LATITUDE 47.43099 LONGITUDE -122.18355
PROJECT NUMBER ES-9583 PROJECT NAME Bales Place Short Plat
GE
N
E
R
A
L
B
H
/
T
P
/
W
E
L
L
-
9
5
8
3
.
G
P
J
-
G
I
N
T
U
S
.
G
D
T
-
2
/
2
1
/
2
4
15365 NE 90th Street, Suite 100
Redmond, WA 98052
Office (425) 449-4704 | esnw.com
Branch Office: Pasco, WA
TESTS
U.
S
.
C
.
S
.
MATERIAL DESCRIPTION
GR
A
P
H
I
C
LO
G
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
502.0
501.0
496.0
GB
GB
MC = 22.4
MC = 13.4
SM
TPSL
SM
Brown silty SAND with gravel, loose, wet (Fill)
-probed 12"
Dark brown TOPSOIL with minor root intrusions
-moderate groundwater seepage at 3'
Gray silty SAND, dense, moist
-mottling, weakly cemented
-probed 3"
-elevated moisture content due to seepage entering test pit above
-mottling ends
-becomes very dense
Test pit terminated at 8.0 feet below existing grade. Groundwater seepage encountered at3.0 feet during excavation. No caving observed.
LIMITATIONS: Ground elevation (if listed) is approximate; the test location was notsurveyed. 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 acomplete understanding of subsurface conditions.
2.0
3.0
8.0
SA
M
P
L
E
T
Y
P
E
NU
M
B
E
R
DE
P
T
H
(f
t
)
0.0
2.5
5.0
7.5
PAGE 1 OF 1
TEST PIT NUMBER TP-4
CHECKED BY HTW
NOTES
SURFACE CONDITIONS Grass
AT TIME OF EXCAVATIONAT TIME OF EXCAVATION
AFTER EXCAVATION
EXCAVATION CONTRACTOR Client Provided
DATE STARTED 1/26/24 COMPLETED 1/26/24
GROUND WATER LEVEL:
GROUND ELEVATION 504 ft
LOGGED BY JMN
LATITUDE 47.43102 LONGITUDE -122.18294
PROJECT NUMBER ES-9583 PROJECT NAME Bales Place Short Plat
GE
N
E
R
A
L
B
H
/
T
P
/
W
E
L
L
-
9
5
8
3
.
G
P
J
-
G
I
N
T
U
S
.
G
D
T
-
2
/
2
1
/
2
4
15365 NE 90th Street, Suite 100
Redmond, WA 98052
Office (425) 449-4704 | esnw.com
Branch Office: Pasco, WA
TESTS
U.
S
.
C
.
S
.
MATERIAL DESCRIPTION
GR
A
P
H
I
C
LO
G
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
499.0
498.0
492.0
GB
GB
GB
GB
GB
MC = 14.9Fines = 37.3
MC = 49.8
MC = 15.5
MC = 18.1
MC = 16.6
SM
TPSL
SM
Brown silty SAND, loose, moist (Fill)
[USDA Classification: slightly gravelly sandy LOAM]
-probed 14"
Dark brown TOPSOIL
-moderate groundwater seepage at 3'
Gray silty SAND, dense, moist to wet-probed 4"
-mottling to 7', weakly cemented
-becomes very dense
-elevated moisture content due to seepage entering test pit above
Test pit terminated at 9.0 feet below existing grade. Groundwater seepage encountered at
3.0 feet during excavation. No caving observed.
LIMITATIONS: Ground elevation (if listed) is approximate; the test location was notsurveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely onthis test log as a standalone document. Refer to the text of the geotechnical report for a
complete understanding of subsurface conditions.
2.0
3.0
9.0
SA
M
P
L
E
T
Y
P
E
NU
M
B
E
R
DE
P
T
H
(f
t
)
0.0
2.5
5.0
7.5
PAGE 1 OF 1
TEST PIT NUMBER TP-5
CHECKED BY HTW
NOTES
SURFACE CONDITIONS Grass
AT TIME OF EXCAVATIONAT TIME OF EXCAVATION
AFTER EXCAVATION
EXCAVATION CONTRACTOR Client Provided
DATE STARTED 1/26/24 COMPLETED 1/26/24
GROUND WATER LEVEL:
GROUND ELEVATION 501 ft
LOGGED BY JMN
LATITUDE 47.43073 LONGITUDE -122.18291
PROJECT NUMBER ES-9583 PROJECT NAME Bales Place Short Plat
GE
N
E
R
A
L
B
H
/
T
P
/
W
E
L
L
-
9
5
8
3
.
G
P
J
-
G
I
N
T
U
S
.
G
D
T
-
2
/
2
1
/
2
4
15365 NE 90th Street, Suite 100
Redmond, WA 98052
Office (425) 449-4704 | esnw.com
Branch Office: Pasco, WA
TESTS
U.
S
.
C
.
S
.
MATERIAL DESCRIPTION
GR
A
P
H
I
C
LO
G
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
Earth Solutions NW, LLC
Appendix B
Laboratory Test Results
ES-9583
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A
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
LL
TP-02
TP-02
TP-03
TP-05
3/4
U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS
GRAVEL SAND
19
19
19
19
%Silt
TP-02
TP-02
TP-03
TP-05
2 2003
Cc CuClassification
%Clay
16
PID60 D30
coarse SILT OR CLAYfinemedium
GRAIN SIZE IN MILLIMETERS
3/8 50
4.0ft.
7.0ft.
4.0ft.
1.0ft.
4.00ft.
7.00ft.
4.00ft.
1.00ft.
PL
3
D100
140
Specimen Identification
1
fine
6
HYDROMETER
304
34.5
29.3
34.1
37.3
101/2
COBBLES
Specimen Identification
4
coarse
20 401.5 8 14
USDA: Gray Gravelly Sandy Loam. USCS: SM.
USDA: Gray Slightly Gravelly Sandy Loam. USCS: SM.
USDA: Gray Slightly Gravelly Sandy Loam. USCS: SM.
USDA: Brown Slightly Gravelly Sandy Loam. USCS: SM.
6 60
PE
R
C
E
N
T
F
I
N
E
R
B
Y
W
E
I
G
H
T
D10
0.079
0.289
0.382
0.271
0.256
GRAIN SIZE DISTRIBUTION
100
PROJECT NUMBER ES-9583 PROJECT NAME Bales Place Short Plat
GR
A
I
N
S
I
Z
E
U
S
D
A
E
S
-
9
5
8
3
B
A
L
E
S
P
L
A
C
E
S
H
O
R
T
P
L
A
T
.
G
P
J
G
I
N
T
U
S
L
A
B
.
G
D
T
2
/
1
3
/
2
4
15365 NE 90th Street, Suite 100
Redmond, WA 98052
Office (425) 449-4704 | esnw.comBranch Office: Pasco, WA
Docusign Envelope ID: B29EB968-C739-45B8-8E1F-7522EE3C1A3A