HomeMy WebLinkAboutGeoTech Report Resubmittal Request for BLD2007-01923 - BLD Engineering / Geo-tech Reports - 5/14/2004 V e c t o r
E N G I N E f R I N G I N C
309 WASHINGTON STREET NE • OLYMPIA WA 98501• TEL: 360 352-2477• FAX: 360 352-0179
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November 26,2007 LIMZCD - PLANINIIINC,
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Mr.Robert D.Fink,AICP
Mason County—Department of Community Development
Mason County Bldg 1
P.O.Box 279
Shelton,WA 98584
Subject: Geotechnical Report Resubmittal Request
Permit#s:BLD 2007-01923
Parcel No.322245000031
Applicant:NORRIS N&NARY M SUDER
Planner: Chuck McCoy
VEI#: 7054-031
Dear Mr.Fink,
The geotechnical report dated May 14, 2004 prepared by GeoResources, 5113 Pacific Hwy,
Suite 1-I, Fife, Washington 98424.2649 for a proposed single family residence remodel and
addition 11301 NE North Shore Road, Belfair, WA 98528 was received and reviewed by
Vector Engineering,Inc.
The Department of Community Development requested the review for the purpose assisting
the Department in determining the amount of potential for landslide activity and the proposed
development would not cause significant adverse impacts or there is adequate geological
information available on the area to determine the impacts of the proposed development and
appropriate mitigating measures. The Department of Community Development reviews all
development applications to determine if they are likely to be in or near a landslide hazard
area per Mason County Resource Ordinance (MCRO), Geologically Hazardous Areas,
Landslide Hazard Areas 17.01.100, Seismic Hazard Areas 17.01.102, and Erosion Hazard
Areas 17.01.104 approved December 27,2006.
Since the report is over three years old and does not conform to the requirements of the latest
ordinance,we regret to say that we cannot recommend approval of the report.
It is recommended the applicant ask the preparer of the report to revise the report as needed
and then resubmit.
Page 1 of 2
XA7000 Files\7054 Mason County Geotech Reviewsk7054-031 Mason_Co(Suder)Wdmin\Transmittal Letters\Geotechnical Report
BLD 2007-01923 Review 1st request Letter 071126.doc
t •
We have enjoyed working with you on this geotechnical review to support the goals of the
Department of Community Development of Mason County, Washington. We look forward to
completing this review when the requested items are provided.
Please feel free to contact me if you have any questions regarding these comments, or if you
feel any features need further discussion or attention.
Sincerely,
Russell W. La Force, P.E.
Design Engineer
Page 2 of 2
XA7000 Files\7054 Mason County Geotech Reviews\7054-031 Mason_Co(Suder)\Admin\Transmittal Letters\Geotechnical Report
BLD 2007-01923 Review 1st request Letter 071126.doc
' GeoResources, LLC
Ph. 253-279-1023 5113 Pacific Hwy. E., Ste. 1-I
Fx. 253-638-8992 Fife, Washington 98424-2648
May 14, 2004
Mr. Norris Suder
13035 15th Avenue NE
Seattle, WA 98125
v Geotechnical Report
,toy, Proposed Residential Remodel
11W) North Shore Road
Lot 17 Div 14
Mason County, WA
JobNo:SuderN.01 R
INTRODUCTION
This report summarizes our site observations, provides our opinion regarding development
of the site and addresses Mason County sensitive area regulations. The site is generally located in
Section 24,T22N, R3W, along the shoreline of Hood Canal, some 11 miles outside of Belfair. The
existing home on the property is a waterfront cabin accessed by stairs from North Shore Road. We
understand that you wish to remodel the existing residence and construct an addition to the rear of
the existing residence. The new addition will be two stories in height. The addition area is between
the existing residence and an existing concrete retaining wall.The retaining wall is located at the
base of a steeply descending hillside that is situated above the home in a level area below the wall.
Portions of the lot slope at greater than 40 percent and have a vertical height of greater than 10
feet. Mason County therefore requires a geotechnical report be prepared to address slope stability
and provide geotechnical recommendations and design criteria for the proposed single-family
residence addition at the site.
Our services are provided at your request and are based on our site meeting with you, our
experience in the area, and our site observations, and discussions with County staff. We
understand that you propose to remodel the single-family residential structure at the site. We
further understand that conventional construction methods will be used. The purpose of our
services is to address the landslide and erosion hazard issues at the site per the Mason County
SAO (Sensitive Area Ordinance) and provide geotechnical recommendations and design criteria
for the proposed residential site improvements. The project site and vicinity are shown on the
Vicinity Map, Figure 1. Specifically, the scope of services for this project will include the following:
1. Review the available Critical Area, geologic, hydrogeologic and geotechnical data for the
site area.
2. Conduct a detailed geologic reconnaissance and slope mapping of the site area,
including exposures of the dense, native"hardpan", supplemented by hand auger test
borings at selected representative locations.
3. Conduct a computer generated slope stability analysis using the XSTABL program.
4. Address the appropriate geotechnical regulatory requirements for the proposed site
development,and slope mitigation measures.
5. Provide geotechnical recommendations for site grading including site preparation,
subgrade preparation, fill placement criteria, suitability of on-site soils for use as
structural fill, temporary and permanent cut and fill slopes, and drainage and erosion
control measures.
6. Provide recommendations and design criteria for foundation and floor slab support,
including allowable bearing capacity, subgrade modulus, lateral resistance values and
estimates of settlement.
Suder Residential Remodel
May 14, 2004
Page 2
7. Provide recommendations and design criteria for design of conventional
subgrade/retaining walls, including backfill and drainage requirements, lateral design
loads, and lateral resistance values, and the possible use or extension of the existing wall
to support the new construction.
8. Provide stormwater runoff control recommendations.
SITE CONDITIONS
SURFACE
The existing home at the site is located slightly above beach level and is currently
accessed by steps descending from a parking area located approximately 6-feet below the grade
of North Shore Road. Existing residential structures are located adjacent to the site. The slope
area across North Shore Road is currently undeveloped. A site plan or architectural drawing of the
site was unavailable at the time this report was prepared. A Site Sketch indicating the approximate
and relative location of site features is attached as Figure 2.
The ground surface at the proposed residential addition area is nearly level, but is situated
at the base of a steeply descending slope between the existing concrete retaining wall and the
parking area. The uphill side of the addition area is protected by the existing concrete wall. The
construction details of the existing wall (age, reinforcement,foundation size) are unknown, and
portions of the walls are out of plumb and leaning outwards slightly from the slope.The portion of
the site slope between the parking area and the wall is densely vegetated with mature evergreen
trees and sparse underbrush. The trees are vertical in orientation and do not exhibit"pistol' butt
trunks indicative of soil creep or solifluxion. The site slope between the parking area and the home
were measured at slopes of between 85 and 100 percent. Offsite, across the road, we measured
slopes as steep as 135 per cent. The vertical height of the steeper slope area on site is on the
order of 40-feet in height.
SUBSURFACE AND GEOLOGIC CONDITIONS
As part of our site reconnaissance, we completed a series of hand auger explorations at
selected representative locations across the site. Soil conditions at specific exploration locations
were logged in the field. The conditions encountered in the individual hand auger explorations
were logged in accordance with the Soil Classification system summarized on Figure 3. Logs of
the individual hand auger explorations are included as Figure 4.
Near surface soils at the site generally consist of dense sands and gravel with variable silt,
cobbles and boulders. The dense sands and gravels are exposed in outcrop in numerous locations
on the uphill side of North Shore Road in the project vicinity. These soils are interpreted to be
glacial outwash related to the Vashon glacial period or older deposits. Our site exploration
encountered cemented sands and gravels in the crawl space below the cabin. These cemented
soils may be older deposits (Salmon Springs) and are very dense and cemented. The slope area
above the home is mantled by a thin deposit of topsoil and forest duff. The native soils below the
topsoil observed at the site were generally in a dense to very dense condition. Natural weathering
processes have disturbed the surficial soils at the site to a loose to medium dense condition. No
groundwater seepage or spring activity was observed in the sloping area of the site at the site at
the time of our site visit. Portions of the slope area below the home outboard of a newly
constructed concrete bulkhead are intermittently submerged, depending on tidal fluctuations.
CONCLUSIONS
GENERAL
Our studies included review of the available data, our site reconnaissance and hand auger
explorations. We have also modeled the site slopes using a computer-aided slope stability
program, XSTABL. Based o our studies, it is our opinion that the site soils are generally stable
under the existing conditions. It is also our opinion that the proposed residential remodel will not
adversely impact the stability of the site. This report contains the results of our stability analysis, as
Suder Residential Remodel
May 14, 2004
Page 3
well as slope mitigation measures by vertically extending the existing retaining wall to protect the
proposed addition area. The Vashon soils and Salmon Springs deposits at the site are in a dense
to very dense condition. Surficial soils at the site have been disturbed through natural weathering
processes and are presently in a loose to medium dense condition. The very dense site soils have
a slight to moderate erosion hazard if undisturbed, especially in the heavily vegetated area;
however, the loose to medium dense soils mantling the slopes will likely represent a severe
erosion hazard if disturbed.
Based on our understanding of the project, it is our opinion that the site soils will provide
adequate support for the structure provided they are prepared in accordance with the standards of
practice for the Puget Sound area and the recommendations provided herein. Geotechnical
guidelines and recommendations for the proposed residential structure are provided below:
LANDSLIDE HAZARD
Although portions of the site meet the technical criteria of a Landslide Hazard area, it is our
opinion that the site soils generally stable in their present condition. The construction of the
residential addition at the site will not have any adverse impact on the stability of the slopes.
Because the proposed addition area is currently occupied by the existing shed roof addition and
patio, no significant increase in impervious area or storm water runoff is anticipated. Significant
slope movement typically occurs during or following significant or extended periods of
rainfall/precipitation. Although proper planning, design, drainage and construction techniques can
reduce the risk of significant erosion and slope instability, there is an inherent risk of instability
associated with steep shoreline sites.
Slope Stability Analyses
Slope stability analyses were completed for the site-specific conditions at the site using the
computer program XSTABL. ractors-of-Safety were calculated for a series of 50-trial failure
surfaces using soil profiles based on the subsurface conditions encountered in our explorations,
and observed on the sloping portions of the site. The Subsurface Cross Section selected for
analysis is illustrated on Figure 5. The cross section selected for study is attached which indicates
the soil profile and soil parameters input.
With respect to more substantial deep-seated failure modes, our analysis indicates the
static factor of safety for the existing slope condition is 1.56. The critical failure surface is the trial
surface which results in the lowest calculated factor-of-safety. The factor of safety calculated for
the critical failure surfaces for the static and seismic stability analyses described herein are
reported on Figure 5. We also modeled the existing slope in a seismic event using a pseudo-
static horizontal acceleration coefficient equal to 0.15 g. For this case, a seismic factor of safety
equal to 1.21 was computed.
These factors of safety reflect an acceptable stability regime at the site. A Factor of Safety
above 1.5 is considered acceptable for structures using static analyses. The 2001 earthquake
event in the Puget Sound area was a 6.8 seismic event. This seismic event effectively provided an
in-situ test of slope stability during a design level seismic event. Anecdotal information indicates
no evidence of slope instability was observed in the slope area or the proposed building site as a
result of the 2001 Nisqually event. The reported seismic factor of safety is above unity.
SEISMIC- LIQUEFACTION HAZARDS
According to the Seismic Zone Map of the United States contained in Figure 16-2 of the
1997 UBC (Uniform Building Code), the project site is located within Seismic Risk Zone 3. Based
on the subsurface conditions observed in the majority of the site, we interpret the site conditions
to correspond to a seismic Soil Profile type So, for Dense Soil, as defined by Table 16-J (UBC).
This is based on the range of equivalent SPT (Standard Penetration Test) blow counts and the
density of soils disclosed in the hand auger explorations. Based on our understanding of the
regional geology, the very dense soil conditions were assumed to be representative for the site
conditions beyond the depths explored.
Suder Residential Remodel
May 14, 2004
Page 4
Based on our review of the subsurface conditions, we conclude that the site soils are not
susceptible to liquefaction. The underlying soils at the sites consist of very dense sand and gravel.
Shaking of these already dense soil is not apt to produce a denser configuration and subsequently
excess pore water pressures are not likely to be produced. The home addition will be supported on
conventional foundations that would transfer the building loads to the medium dense granular soils at
depth.
EROSION HAZARDS
The loose to medium dense soils mantling the slopes will likely represent a severe erosion
hazard if disturbed. However, it is our opinion that the potential erosion of the site is not a limiting
factor for the proposed development. Development at the site will be restricted to the lower portion
of the lot which is currently cleared of vegetation and occupied by a portion of the existing
residence and patio. Erosion control measures may include, but not necessarily limited to, berms
and swales with check dams to channel surface water runoff, ground cover/protection in exposed
areas and silt fences. Graded areas should be shaped or otherwise protected to avoid
concentrations of runoff onto cut or fill slopes, natural slopes or other erosion-sensitive areas.
Temporary ground cover/protection such as jute matting, excelsior matting, wood chips or clear
plastic sheeting should be used until permanent erosion protection is established.
All disturbed areas represent an increased risk for erosion. We therefore recommend that
temporary and permanent erosion control measures be installed and maintained during construction
and following, until permanent erosion control or landscaping is in place. Collected stormwater from
the addition's roof should be collected and be discharged directly to Hood Canal.
EARTHWORK
Site Preparation
Based on our review of the site plan and our discussions with you, additional grading at the
site will be minimal and generally consist of the excavation of the foundation for the addition. We
expect that grading at the site can be accomplished with conventional earth moving equipment. The
site soils generally consist of sand and gravel with variable silt and cobble content. These soils may
be used as structural fill during dry and moderate wet weather conditions.
Structural Fill
No additional significant earthwork is expected at the site. The following recommendations
are provided in the event that plans change.All fill material used to achieve design grades within the
building and driveway areas should be placed as structural fill. The structural fill should be placed in
horizontal lifts of appropriate thickness to allow adequate and uniform compaction of each lift. Fill
placed in the building and pavement areas should be compacted to a firm and unyielding surface.
The appropriate lift thickness will depend on the fill characteristics and compaction
equipment used. We recommend that the appropriate lift thickness be evaluated by our field
representative during construction. For planning purposes, we recommend a maximum loose-lift
thickness of 12 inches. We recommend that our representative be present during site grading
activities to observe the work and perform field density tests.
The suitability of material for use as structural fill will depend on the gradation and moisture
content of the soil. As the amount of fines (material passing No. 200 sieve) increases, soil becomes
increasingly sensitive to small changes in moisture content and adequate compaction becomes more
difficult to achieve. If it is hecessary to import structural fill material to the site,we recommend that fill
material consist of well-graded sand and gravel with less than 5 percent passing the No. 200 sieve
based on that fraction passing the 3/4-inch sieve. During prolonged dry weather conditions, a
somewhat higher(up to 10 to 12 percent)fines content will be acceptable.
Material placed for structural fill should be free of debris, organic matter,trash and cobbles
greater than 6 inches in diameter. Particle sizes larger than 3 inches should be excluded from the top
1-foot of fill. The moisture content of the fill material should be adjusted as necessary for proper
compaction.
Suder Residential Remodel
May 14, 2004
Page 5
Suitability of On-Site Materials as Fill
During dry weather construction, any nonorganic on-site soil may be considered for use as
structural fill, provided it meets the criteria described above in the structural fill section and can be
compacted as recommended. If the material is over the optimum moisture content(typically 2 to 4
percent)when excavated, it will be necessary to aerate or dry the soil prior to placement as structural
fill.
The workability of material for use as structural fill will depend on the gradation and moisture
content of the soil. As the amount of fines increases soil becomes increasingly more sensitive to
small changes in moisture content and adequate compaction becomes more difficult or impossible to
achieve.
In general,the soils observed at the site consist of sand and gravel with variable silt and
cobble content. These materials are suitable for use as structural fill during dry and moderately wet
conditions. It may be necessary to moisture condition these soils prior to use as structural fill,
particularly during dry weather conditions.
CUT AND FILL SLOPES
Temporary cut slopes (foundation and utility excavations) may be necessary during grading
operations. As a general guide,temporary slopes of 1.5 to 1 (horizontal to vertical) or flatter may be
used for temporary cuts in the upper 3 to 5 feet of medium dense to dense soils. Temporary slopes
of 1 to 1 or flatter may be used in the unweathered dense to very dense sands and gravels or till.
These guidelines assume that all surface loads are kept at a minimum distance of at least one half
the depth of the cut away from the top of the slope and that significant seepage is not present on the
slope face. Flatter cut slopes will be necessary if/where significant soil moisture or seepage occurs.
In the event that permanent cut and fill slopes are required, we recommend a maximum of 2
to 1 slope.Where 2 to 1 slopes are not feasible, retaining structures should be considered. Fill placed
on slopes that are steeper than 5 to 1 should be"keyed" into the undisturbed native soils by cutting a
series of horizontal benches. The benches should be 11/2 times the width of equipment used for
grading and a maximum of 3 feet in height. Subsurface drainage may be required in seepage areas.
Surface drainage should be directed away from all slope faces. Some minor raveling may occur with
time. All slopes should be seeded as soon as practical to facilitate the development of a protective
vegetative cover or otherwise protected.
BUILDING FOUNDATIONS
Conventional spread footings are recommended for support of the residential addition.For
structures bearing on medium dense native soil, we recommend an allowable soil bearing pressure of
2,000 pounds per square foot(psf)for combined dead and long-term live loads, exclusive of the
weight of the footing and any overlying backfill. A higher bearing pressure of 3,000 psf may be used if
the footings extend to the dense to very dense soils encountered below 3-feet in the addition area.
These values may be increased by one-third for transient loads such as those induced by seismic
events or wind loadings.
We recommend a minimum width of 18 inches for isolated footings and 16 inches for
continuous wall footings. All exterior footing elements should be embedded at least 18 inches below
the lowest adjacent finished grade. We recommend that any disturbed soils in the footing
excavations be removed, or if practical, recompacted prior to concrete placement
We estimate that'settlements of footings designed and constructed as recommended will be
less than 1/2 inch, with differential settlements between comparably loaded footings of 1/2 inch or
less. These settlements will occur essentially as loads are applied. Disturbance of the foundation
subgrade during construction could result in larger settlements than predicted.
FLOOR SLAB SUPPORT
Slabs-on-grade should be supported on dense native soil or on structural fill prepared as
recommended. We recommend that floor slabs at the site be underlain by a 6-inch thickness of
uniformly graded gravel or sand containing no more than 3 percent fines to provide a capillary break.
Suder Residential Remodel
May 14, 2004
Page 6
The capillary break material should be placed in one lift and compacted to a firm and unyielding
surface. The capillary break material should be connected to a suitable drain outlet to provide an exit
for any accumulated seepage. Where the native soils meet this criteria, they are considered suitable
for use as the capillary break.
A vapor barrier, such as a polyethylene liner is recommended where the native or fill soils
contain greater than 3 percent fines. A thin layer of"clean" sand may be placed over the vapor
barrier and immediately below the slab to protect the polyethylene liner during steel and/or concrete
placement.
A subgrade modulus of 250 kcf (kips per cubic foot) may be used for design. We estimate
that settlement of the floor slabs designed and constructed as recommended, will be 112 inch or less
over a span of 50 feet.
LATERAL RESISTANCE
Lateral loads may be resisted by friction on the base of footings and floor slab and as passive
pressure on the sides of footings. We recommend a coefficient of friction of 0.65 be used to calculate
friction between the concrete and very dense soil. Passive pressure may be determined using an
equivalent fluid weight of 300 pcf (pounds per cubic foot) above the water table, and 160 pcf for
saturated soils. This assumes that structural fill is placed against the sides of the footings and that
the top of the fill is confined by either a concrete floor slab or pavement. A safety factor of 1.5 is
conventionally applied to these values.
RETAINING BASEMENT WALL
Because of the uncertainties regarding the details and integrity of the existing concrete wall at
the site,we do not recommend this wall be relied upon to protect the new addition. In addition, even
though adequate factors of safety were indicated for deep-seated failures at the site,there is a risk of
surficial sloughing. Because of the steep slope above the addition area, and the presence of large
trees on the slope,we recommend that a new retaining wall be constructed against the toe of slope
and extend above the existing top of wall by a minimum of 5-feet.The wall extension would provide a
catchment area to protect the addition from the potential for minor surficial sloughing failures. The
existing wall can remain in place and serve as a portion of the back form for the new wall. In addition,
we recommend that no penetrations or openings (windows or doors) be constructed in the addition on
the side of the structure facing the slope.
The proposed retaining wall can be supported on conventional shallow footings founded on
medium dense native soils or structural fill, if properly prepared. Footings bearing on undisturbed
native soils or structural fill as described above can be designed using an average allowable bearing
value of 2,000 psf with a maximum toe pressure of 3,000 psf. Footings extended to bear on the
dense to very dense soils may be designed to exert an average allowable bearing pressure of 3,000
psf,with a maximum toe pressure of 4,000 psf.
Lateral loads on conventional retaining structures founded as described above may be
resisted by friction on the base of the wall footings and as passive pressure on the sides of footings.
We recommend using an ultimate coefficient of friction of 0.65 to calculate friction between the
concrete and dense native soils or on structural fill. Passive pressure may be determined using an
equivalent fluid weight of 300 pcf. This assumes that structural fill is placed against the sides of the
footings. A safety factor of 1.5 should be applied to these values,for sliding and overturning.
The lateral active'soil pressures acting on reinforced concrete retaining walls depend on the
nature, density and configuration of the soil behind the wall. We recommend that portions of walls
supporting horizontal backfill be designed using an equivalent fluid density of 35 pcf for a level back-
slope behind the wall. For the condition of the steep slope above the wall (85 per cent),we
recommend a lateral design pressure equal to 65 pcf be used. The recommended pressure does not
include the effects of surcharges from surface loads.
Adequate drainage behind an retaining structure or sub grade wall is imperative. The actual
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condition of the drainage system for the existing wall is not known. To promote drainage through the
existing wall, we recommend the wall be penetrated with small diameter weep holes at the base of
Suder Residential Remodel
May 14, 2004
Page 7
the existing wall on a horizontal spacing no greater than 10-feet on center. Seepage from the weep
holes should be collected and manifolded to an appropriate discharge point. If the existing wall is
utilized as a back form for the new wall,we recommend the space between the walls include a
drainage medium, such as Miradrain or other proprietary drainage material. If the new wall is set
forward of the existing wall, in addition to the weep holes, we recommend that a drainage system
consisting of a minimum 12 inches of clean sand and/or gravel with less than 3 percent fines be
placed along the back of the wall. The drainage collector system consisting of 4-inch perforated PVC
pipe should be installed between the two walls to provide an outlet for any accumulated water. The
drainage material should be capped at the ground surface with 1-foot of relatively impermeable soil or
otherwise sealed.
SITE DRAINAGE
All ground surfaces, pavements and sidewalks at the site should be sloped away from
structure. Surface water runoff should be controlled by a system of sloping surfaces, curbs, berms,
drainage swales, and/or catch basins, and conveyed to an appropriate discharge point at the
shoreline. Drains should be provided behind all retaining walls.
We recommend that roof runoff at the site be collected and discharged to the Hood Canal.
No significant increase in hard surface area is anticipated because the addition area is currently
occupied by an existing patio and shed roof addition. Driveway runoff should be sheet flowed to
the adjacent vegetation.
LIMITATIONS
We have prepared this report for use by the Suder's and members of their design team,for
use in the design of a portion of this project. The data and report should be provided to prospective
contractors for their bidding or estimating purposes only. Our report, conclusions and interpretations
should not be construed as a warranty of the subsurface conditions.
Variations in subsurface conditions are possible between the available explorations (well)and
may also occur with time. A contingency for unanticipated conditions should be included in the
budget and schedule. Although proper planning, design, drainage and construction techniques can
reduce the risk of significant erosion and slope instability, there is an inherent risk of instability
associated with steep shoreline bluff sites.
The scope of our services does not include services related to environmental remediation
and construction safety precautions. Our recommendations are not intended to direct the contractor's
methods,techniques, sequences or procedures,except as specifically described in our report for
consideration in design.
If there are any changes in the loads, grades, locations, configurations or type of facilities to
be constructed,the conclusions and recommendations presented in this report may not be fully
applicable. If such changes are made, we should be given the opportunity to review our
recommendations and provide written modifications or verifications, as appropriate.
Suder Residential Remodel
May 14, 2004
Page 8
Within the limitations of scope, schedule and budget, our services have been executed in accordance
with generally accepted practices in this area at the time this report was prepared. No other
conditions, express or implied, should be understood.
Respectfully submitted,
GeoResources, LLC
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Enc: Figure 1-Vicinity Map
Figure 2-Site Sketch
Figure 3-Soil Classification System
Figure 4-Hand Auger Logs
Figure 5- Slope Stability Cross Section
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SOIL CLASSIFICATION! SYSTEM
MAJOR DIVISIONS GROUP GROUP NAME
SYMBOL
GRAVEL CLEAN GW WELL-GRADED GRAVEL,FINE TO COARSE GRAVEL
GRAVEL
COARSE GP POORLY-GRADED GRAVEL
GRAINED More than 50%
SOILS Or Coarse Fraction GRAVEL GM SILTY GRAVEL
Retained on WITH FINES
No.4 Sieve
GC CLAYEY GRAVEL
More than 50°k SAND CLEAN SAND SW WELL-GRADED SAND,FINE TO COARSE SAND
Retained on
No.200 Sieve SP POORLY-GRADED SAND
More than 50%
Of Coarse Fraction SAND SM SILTY SAND
Passes WITH FINES
No.4 Sieve SC CLAYEY SAND
SILT AND CLAY INORGANIC ML SILT
FINE
GRAINED CL CLAY
SOILS Liquid Limit
Less than 50 ORGANIC OL ORGANIC SILT,ORGANIC CLAY
SILT AND CLAY INORGANIC MH SILT OF HIGH PLASTICITY,ELASTIC SILT
More than 50%
Passes CH CLAY OF HIGH PLASTICITY,FAT CLAY
No.200 Sieve
Liquid Limit
50 or more ORGANIC OH ORGANIC CLAY,ORGANIC SILT
HIGHLY ORGANIC SOILS PT PEAT
NOTES: SOIL MOISTURE MODIFIERS:
1. Field classification is based on visual examination of soil Dry- Absence of moisture,dry to the touch
in general accordance with ASTM D248"0.
2. Soil classification using laboratory tests is based on Moist- Dump,but no visible water
ASTM D2487-90. Wet- Visible free water or saturated,usually soil is
3. Description of soil density or consistency are based on obtained from below water table
interpretation of blow count data,visual appearance of
soils,and or test data.
GeoRes®@. rces, I_LC SOIL CLASSIFICATION SYSTEM
5007 Pacific Hwy. E, Ste 20
Fife, Washington 98424-2648
Ph. 253-896-1 all
Fx. 253-896-2633 FIGURE 3
HAND AUGER LOGS
SUDER RESIDENTIAL PROPERTY
11301 North Shore Road
MASON COUNTY
HA-1-Located upper slope above residence
Depth(ft) Soil TyN Description
0.0 - 0.5 Duff/Topsoil
0.5 - 1.0 SW Lt bm F-M SAND and GRAVEL w/silt,occ. cobbles
(med dense, moist),minor roots
1.0 - 2.0 SW Lt Bm F-M SAND and GRAVEL w/silt,occ.cobbles
(med. dense to dense,moist)
2.0- 2.5 SM Lt brn SAND w/silt,cobbles
(dense to v.dense,moist)
Auger refusal at 2.5
Minor caving observed
No goundwater seepage observed
HA-2-Located mid slope above residence
Depth(ft.) Soil Type Description
0.0 - 0.1 Duff/Topsoil
1.0 - 2.0 SM Bm SAND w/silt,trace gravel
(loose to med dense,moist)
2.0 - 3.5 SP Bm silty SAND w/trace gravel,
(loose to med.dense,moist)
3.5 - 5.0 GM Bm silty GRAVEL w/sand,om Cobbles
(med dense,damp)
5.0 - 5.5 SM/GM Brn silty SAND and GRAVEL w/occ. Cobbles
(wet,dense)
Minor caving observed
Minor groundwater seepage at 4.5-feet
HA-3-Located at base of concrete retaining wall
Depth(ft.) Soil Type Description
0.0 - 0.2 Duff/Topsoil
0.2 - 1.0 SP Lt.brn SAND w/silt,
(med dense,moist)
1.0 - 3.0 SW Bm/gray SAND w occ. gravel
(med dense,wet)
3.0 - 3.5 SW Gray SAND w/gravel,occ. Cobble, trace silt
(dense,wet)
Petroleum odor below 3-feet
Minor caving observed#1-foot
Minor goundwater seepage observed
HAND AUGER LOGS
SUDER RESIDENTIAL PROPERTY
11301 North Shore Road
MASON COUNTY
HA4-Located in crawls I pace below residence
Depth(ft.) Soil Tune Description
0.0 - 1.0 SP/SW Brn Med SAND w/gravel,trace silt
(med dense,moist)
>1.0 SW/GW Brn/gray SAND and GRAVEL w/cobbles,silt
(cementd, dense,moist-damp)
Auger refusal
No caving observed
No goundwater seepage observed
HA-5—Above rockery in parking area
Depth(ft.) Soil Type Description _
0.0 - 0.5 SW Bm SAND w/gravel(FILL)
(loose, moist)
>1.0 SW Lt bm F-M SAND w/gravel
(dense to v.dense,moist),minor roots
Auger refusal at 1-foot
Minor caving observed
No goundwater seepage observed
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FIGURE 5
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