HomeMy WebLinkAboutGeoTech Review for BLD2003-01184 - BLD Engineering / Geo-tech Reports - 10/10/2003 MASON COUNTY
PUBLIC WORKS DIRECTOR/COUNTY ROAD ENGINEER
Shelton,Washington 98584
DATE: October 10'h 2003
INTER-DEPARTMENTAL COMMUNICATIONS
TO: Rick Mraz, DCD - Planner
FROM: Alan A. Tahja,P/W-Co. Hydr. Engr. WO#PLG-03
SUBJ: Geo-Tech Report Review NAME: Loudin SFR a, 301 East Larson Blvd
BLD2003-01184
Rick,
The geotechnical report prepared for the Mike&Jill Loudin Single Family Residence (SFR),has
been received and reviewed by Public Works.
The report appears to satisfactorily address County requirements for geotechnical reporting. The
report's author indicates that, in his opinion,the proposed development of the property will not
cause stability problems for either the subject property or neighboring properties. From the
contents of the report,I recommend accepting the report as satisfying the County's
requirement(s)for stability investigation. Recommendations contained in the report should be
incorporated into the site's development(8' building setback from the lower slope, and a 4'
building setback from the bank behind the building location)and made conditions for permit
issuance.
With the engineer's recommendations incorporated into the site's development, stability issues
appear to have been adequately addressed.
Adequate erosion and sediment control features need to be implemented during land disturbing
activities to protect neighboring properties and State waters from adverse stormwater runoff
impacts. The migration or release of silty water or mud from the applicant's property will be
considered a violation of County and State water quality protection regulations.
In summary,the geotechnical report appears acceptable,and the residential development of the
property should be allowed to proceed, subject to the engineer's recommendations.
Please feel free to contact me at County extension 461 if you have any questions regarding these
comments, or if you feel any features need further discussion or attention.
XY1
_A_ Wli�
An A. Tahj
File: H: \WP\GEO\Reviews\Loudin.doc
I
WORK ORDER - PUBLIC WORKS DEPT.
(AI Date: (o G
PERMIT#: (>7 Work Order
3- Ig`� Number:
Requested by:
Authorized by: Date:
Type of Work:
CHARGE TO:
NAME
AGENCY/COMPANY
BILLING ADDRESS
PHONE u
Pub. Works Person In Charge: -
(C) Project Time Line. (from -to dates) a TO
Project Start data: D—(O —03 Estimated FWsh Date:
Awmd-nate h"z: I ESTIMATED TOTAL
COST ESTIMATE
tDl Employog
2i Fri"t% TOTAL$
,� z Z
03 ��T� �� 1�� zz
S�II BATE EQUIPMENT USED: TOTAL t'S
MATERIAL USED:
�:.<.c.•.ee..aa«:�,.i ""` .. ..:,,.o'�=. >x,�:l�$��Q��T o c..^,r<a�?-'z�t',,,�` �.�3:.hBM-�:s:.:w?�-0�"%i��ti;="%-csK
�iwV..'�$ci4i�.�ucs�/;��.7::viLieL.�6�.3aw�6o�cKee'v:::ec ,,, - r:'"":`,:y•�:�>.^;✓^`�".•..-..�>'.,,> :>;x
(F) Actual Cost = BARS: PROJ#-
DATE Employee
Name S Rye Flours 1qtiQW Edna—S TOTAL$
EQUIPMENT USED: Qa�q l�ji at TOTAL SS
MATERIAL USED:
TOTAL ALL
(G) BILLED GATE INV I PAID DATE REC.I— CKS
r,n
Geotechnical Report RECEIVED
OCT 0 2 XT
301 East Larson Blvd. BELFAIR OFFICE
Mason County, WA
Parcel #123305100080
Prepared for
Mike and Jill Loudin
Belfair, WA
by
Geotechnical Testing Lab
Olympia, WA
September 27, 2003
GEOTECHNICAL TESTING LABORATORY
MIKE& JILL LOUDIN
P.O. Box 1634
BELFAIR, WA 98528
Re: Geotechnical Report
301 East Larson Blvd.
Parcel 123305100080
N47027.105' W122050.912'
INTRODUCTION
This report summarizes the results of our geotechnical consulting services for the mobile home replacement located
at the above referenced site, approximately one mile west of Belfair, Washington. The location of the site is shown
relative to the surrounding area on the Vicinity Map, Figure 1.
Our understanding of the project is based on our discussions with you and our explorations and review of the site.
The site is accessed by a driveway from East Larson Blvd. In general, grading will consist of the excavation of the
foundation and footings.
F
The steepest slope measured onsite was in excess of 40 percent, located on the north side of the proposed building
area. Therefore, Mason County requires that a geotechnical report be prepared in accordance with the Critical
Areas Ordinance. A 10-foot slope is located offsite to the east.
The purpose of our services is to evaluate the surface and subsurface conditions at the site as a basis for providing
geotechnical recommendations and design criteria for the project and to satisfy the requirements of the Mason
County Critical Areas Ordinance. Geotechnical Testing Laboratory is therefore providing geologic and
hydrogeologic services for the project. Specifically, our scope of services for this project will include the following:
1. Review the available geologic, hydrogeologic, and geotechnical data for the site area.
2. Conduct a geologic reconnaissance of the site area.
3. Investigate shallow subsurface conditions at the site by observing the exposed soil and reviewing published
well logs.
4. Evaluate the landslide and erosion hazards at the site per the Mason County Critical Areas Ordinance
regulations.
10011 Blomberg Street SW, Olympia, WA 98512 1
Phone#:(360)754-4612 Fax#: (360)754-4848
GEOTECHNICAL TESTING LABORATORY
5. Provide geotechnical recommendations for site grading including site preparation, subgrade preparation, fill
placement criteria(including hillside grading),temporary and permanent cut and fill slopes, drainage and
erosion control measures.
SITE CONDITIONS
SURFACE CONDITIONS
E
The proposed building site is located in an area of e
moderate residential development in the Puget Sound `$
Glacial upland, north of the Hood Canal. We
conducted a reconnaissance of the site area on
September 18, 2003. The site slopes toward the south
and southeast. Building site elevations range from
approximately 200 feet to 208 feet with higher
elevations to the north and west. '
1
The building area of the site has vegetation indigenous
to the northwest. The vegetation includes madrona and ro
fir trees as well as ferns, rhododendron, salal, Scot's a
broom, and blackberries.
At the time of the site visit, we observed no evidence of - -
surface erosion. No evidence of deep-seated slope
instability was observed on the site slopes or areas
adjacent to this site at the time of our investigation.
No evidence of surface water flow was observed in the site area at the time of our reconnaissance.
The general topography of the site area indicates that drainage flows toward the south.
_�Y� _ _.. rya►,�. �
9.
u,
a.�n
Yrr
SITE GEOLOGY
The site is generally situated within the Puget Sound glacial lowland. The existing topography, as well as the
surficial and shallow subsurface soils in the area, are the result of the most recent Vashon stade(stage)of the Fraser
glaciation that occurred between about 10,000 and 12,000 years ago, and weathering and erosion that has occurred
since. A description of the surficial soils is included in the"Site Soils"section of this report.
10011 Blomberg Street SW, Olympia, WA 98512 2
Phone#: (360)754-4612 Fax#: (360)754-4848
GEOTECWUCAL TESTING LABORATORY
In general, the soils on the site are predominantly represented by +
Vashon glacial outwash deposits.
•:z
SITE SOILS
The Soil Survey of Mason County, USDA Soil Conservation Service
(1960)has mapped the site soils as an Everett gravelly loamy sand, 5
to 15% slopes(Ee). The Everett soils are described as very deep,
somewhat excessively drained soil found on terraces and outwash
plains, formed in the glacial outwash stage of the most recent Fraser
glaciation. These Everett soils coarsen with depth. Permeability is
rapid(up to 20 inches per hour)with a high rate of water transmission.
These soils are typically classified as"Hydrologic Group A"relative to
surficial runoff. The water capacity for plants is low. The soils are
further characterized as having medium runoff potential and moderate
water erosion potential. Shrink-swell potential is described as low due
to the low organic content.
The project is beyond the scope of The Coastal Zone Atlas, Volume 9,
Mason County.
SUBSURFACE EXPLORATIONS
Subsurface conditions at the site were evaluated by observing the exposed building site soils and reviewing available
well logs. Glacial outwash material is expected to be found to a depth beyond the scope of the project.
SUBSURFACE CONDITIONS
In general, undisturbed dense gravelly sandy loam was observed throughout the site. Groundwater was not observed
or encountered. No instances of seeps of groundwater were seen on the slopes on or adjacent to the parcel. Based
on the site topography and the nature of the near surface soil,seasonally perched groundwater conditions are not
expected during periods of extended wet weather.
SLOPE STABILITY
Slopes in excess of 40 percent were observed on the site, located approximately 30 feet to the southeast of the
building location. Since slopes of 40 percent or greater with 10 feet or more of vertical relief occur on portions of
the site, Mason County requires that a geologic hazards report be completed according to the Critical Areas
Ordinance.
The near-surface gravelly sandy soils are in a dense to very dense condition except at the ground surface. The
surficial soils are generally in a medium dense condition.
In general,the undisturbed native soils of the site consist of a mixture of variable amounts of sand, silt, and gravel.
These soil materials are in a dense condition except where they have been disturbed by weathering activity. These
soils are generally stable relative to deep-seated failure. No evidence of deep-seated landslide activity or significant
erosion was observed at the site at the time of our investigation.
10011 Blomberg Street SW, Olympia, WA 98512 3
Phone#: (360)754-4612 Fax#: (360)754-4848
GEOTECHNICAL TESTING LABORATORY
Weathering, erosion, and the resultant sloughing and shallow landsliding are natural processes that can affect steep
slope areas. Instability of this nature is typically confined to the upper weathered or disturbed zone, which has been
disturbed and has a lower strength. Evidence of minor surficial erosion, raveling and sloughing was not observed on
the sloping areas during of our investigative visit.
Significant weathering typically occurs in the upper 2 to 3 feet and is the result of oxidation, root penetration,
wet/dry cycles, and freeze/thaw cycles. Erosion in steep slope areas such as this can be reduced by encouraging
vegetation and discouraging runoff from the steep slope. Erosion control recommendations for the sloping areas are
provided in the"Erosion Control"section of this report.
CONCLUSIONS AND RECOAUVIENDATIONS
GENERAL
Based on the results of our site reconnaissance and subsurface observations, and our experience in the area, it is our
opinion that the site is suitable for the proposed mobile home replacement.
The slope is stable relative to deep-seated instability and will not be affected by the proposed single-family
residence. Proper drainage control measures will reduce or eliminate the potential for erosion and improve slope
stability. Deep-seated instability is not expected to affect the proposed single-family residence.
In general,the site soils are suitable for use as structural fill material. Although saturated soil conditions are not
associated with these soils during or following extended periods of rainfall, we recommend that earthwork be
undertaken during favorable weather conditions to reduce grading time and construction costs.
Pertinent conclusions and geotechnical recommendations regarding the design and construction of the single-family
residence are presented below.
LANDSLIDE—EROSION HAZARD AREAS
CLASSIFICATION
The Mason County Critical Areas Ordinance(17.01.100)defines a landslide hazard area as one containing slopes
equal to or greater than 40 percent with more than a 10-foot vertical relief. A site slope is in excess of 40 percent
and the vertical relief is in excess of 10 feet. Based on this, this site does meet the technical criteria of a landslide
hazard.
The Mason County Critical Areas Ordinance(17.01.104)defines an erosion hazard area as:
Areas in Mason County underlain by soils which are subject to severe erosion when
disturbed. Such soils include, but are not limited to, those for which potential for erosion
is identified in the Soil Survey of Mason County, USDA Soil Conservation Service, 1960,
or any subsequent revisions or additions to this source. These soils include, but are not
limited to, any occurrence of River Wash ("Ra') or Coastal Beaches ("Cg') and the
following when they occur on slopes 15%or steeper:
a. Alderwood gravelly sandy loam ("Ac"and "Ad')
b. Cloquallum silt loam ("Cd')
c. Harstine gravelly sandy loam ("Hb')
d. Kitsap silt loam ("Kc')
10011 Blomberg Street SW, Olympia, WA 98512 4
Phone#: (360)754-4612 Fax#: (360) 754-4848
GEOTECHINICAL TESTING LABORATORY
The soils at the site are mapped as Everett gravelly loamy sand(E,,). This site does not meet the technical criteria of
an erosion hazard area.
SLOPE STABILITY
Based on our field observations, explorations and our experience with the soil types encountered on the property, we
conclude that although portions of the slopes on the lot exceed 40 percent, they are generally stable relative to deep-
seated failure in their present configuration.
A building setback from landslide hazard areas is required unless evaluated and reduced by an engineering geologist
or a licensed professional engineer. Based on our geotechnical evaluation of the site and our experience in the area,
a building setback will be needed for this lot. We recommend a building setback of 8 feet and a setback of 4 feet for
decks from the top of the immediate slope(eastern). A setback of 6 feet from the toe of the upper(western)slope is
required. The building setback may be measured from the bottom of the footing to the face of the slope, in
accordance with the Unified Building Code. The following figure represents a shear angle for the Everett soils.
Shear angle and cohesion are variables used to model the site.
Peak Shear Stress vs. Normal Stress
3000 40°
2500
2000
�g 1500
y
A 1000
n�.
500 --�-1/4 ton
f 1/2 ton
0 1 ton
0 500 1000 1500 2000 2500 3000
Normal Stress (psf)
Slope stability was modeled using the GEO-SLOPE/W program(version 5.13)in both static and extreme dynamic
conditions(ca=0.3). Factors of safety were determined using Bishop's, Janbu, and the Morgenstern-Price methods.
The site geology was modeled using a monolithic layer of Everett gravelly loamy sand. The Everett soil was
determined to have a unit weight of 132 pcf,cohesion of 200 psf(conservative), and a shear angle(�)of 401. Under
static conditions,the slopes remained stable to deep-seated and shallow failure. Under dynamic loading, the 2816
computations demonstrated that the slope is not susceptible to surficial raveling; large deep-seated failure was not
demonstrated by our model. The following figure illustrates a moment F.S. of 1.68. This solution is the lowest F.S.
generated by the model for the site.
10011 Blomberg Street SW, Olympia, WA 98512 5
Phone#: (360)754-4612 Fax#:(360)754-4848
GEOTEamcAL TESTING LABORATORY
Loudin Site
Analysis Method: Morgenstern-Price
Direction of Slip Movement Left to Right
Slip Surface Option: Grid and Radius
Seismic Coefficient: Horizontal-and Vertical.
230 . . .
220
0 210 —Everett S Areading
M 200 Model M°Fr`C°ul°m
Wei 132 1
E0 190gc�esion:200
180 40
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140
Distance (ft)
Changes in slope stability are not expected to result from minor excavations in the development of the site. Grading
in the building portion of the site should be conducted in accordance with geotechnical recommendations provided
herein.
As previously discussed,weathering,erosion,and the resultant surficial sloughing and landsliding are natural
processes that affect slope areas. Significant weathering typically occurs in the upper 2 to 3 feet and is the result of
oxidation, root penetration, wet/dry cycles and freeze/thaw cycles. No significant surficial raveling or sloughing
was observed in the sloping portions of the site. To manage and reduce the potential for these natural processes, we
recommend the following:
1. No drainage of concentrated surface water or significant sheet flow onto the slope area. Drainage from the
roof shall be collected and tight-lined to the existing discharge area.
2. No filling or cutting within the setback zone unless retained by retaining walls or constructed as an
engineered fill.
SEISMIC—LIQUEFACTION HAZARD
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.
10011 Blomberg Street SW, Olympia, WA 98512 6
Phone#: (360)754-4612 Fax#: (360)754-4848
GEOTECHNICAL TESTING LABORATORY
Based on the subsurface conditions observed at the site, we interpret the site conditions to correspond to a seismic
Soil Profile Type Sc, for Very Dense Soil, as defined by Table 16-J(UBC). This is based on the range of SPT
(Standard Penetration Test)blow counts and/or probing with a'/z-inch diameter steel probe rod. The shallow soil
conditions were assumed to be representative of the site conditions beyond the depths explored.
we conclude that the site soils are not susceptible to liquefaction.
Based on our review of the subsurface conditions, oncl a cep q
The near-surface soils are generally in a dense condition and the static water table is located well below the surface.
Shaking of the already dense soil is not apt to produce a denser configuration and subsequently excess pore water
pressures are not likely to be produced.
EROSION CONTROL
It is our opinion that the potential erosion hazard of the site is not a limiting factor for the development. Removal of
natural vegetation should be minimized and limited to the active construction areas. Landscaping around the
proposed building location is permissible, but understory growth on the slopes should be encouraged as much as
possible as a deterrent to erosion. Trees located on steep slopes may be removed only if the stumps remain to deter
erosion.
Erosion control measures should include, but not be limited to, silt fences, berms and swales with ground
cover/protection in exposed areas. A typical silt fence detail follows this report. Any re-contouring of the site will
create a need for erosion control measures as listed above.
EARTHWORK
SITE PREPARATION
All areas to be excavated should be cleared of deleterious matter including debris, abandoned utilities, and
vegetation. Based on our explorations, we estimate that earthwork shall be composed of the foundation and
footings.
Where placement of fill material is required,the exposed subgrade areas should be cleared of deleterious material to
a firm and unyielding surface prior to placement of any fill. We recommend that trees be removed with the roots, in
the area where fill is to be located. Excavations for tree stump removal in any building area should be backfilled
with structural fill, compacted to the density requirements described in the"Structural Fill"section of this report.
Any soft, loose or otherwise unsuitable areas delineated during construction or probing should be compacted, if
practical, or over-excavated and replaced with structural fill, based on the recommendations of our site
representative.
STRUCTURAL FILL
All fill material 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 should be compacted to at least 90
percent of MDD(maximum dry density as determined in accordance with ASTM D-1557)to within 2 feet of
subgrade and 95 percent MDD in the upper 2 feet.
10011 Blomberg Street SW, Olympia, WA 98512 7
Phone#: (360)754-4612 Fax#: (360)754-4848
GEOTECHNICAL TESTING LABORATORY
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.
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.
During wet weather, we recommend the use of well-graded sand and gravel with less than 5 percent(by weight)
passing the No. 200 sieve based on that fraction passing the%-inch sieve.
If prolonged dry weather prevails during the earthwork and foundation installation phase of construction,a
somewhat higher(up to 10 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. The moisture content of the fill
material should be adjusted as necessary for proper compaction.
SUITABILITY OF ON-SITE SOILS AS FILL
On-site Everett soils may be used as structural fill. In general, the native soils(gravelly sandy loam)encountered on
the site should have less than 10 percent fines(material passing the US No. 200 Sieve)and are suitable for use as
structural fill.
FOUNDATION SUPPORT
We recommend a minimum width of 2 feet for isolated footings and at least 16 inches for continuous wall footings.
Footings founded as described above can be designed using an allowable soils bearing capacity of 2,000 psf(pounds
per square foot)for combined dead and long-term live loads in areas of dense to very dense soils.
The weight of the footing and any overlying backfill may be neglected. The allowable bearing value may be
increased by one-third for transient loads such as those induced by seismic events or wind loads.
Lateral loads may be resisted by friction on the bases of footings and floor slabs and as passive pressure on the sides
of footings. We recommend that an allowable coefficient of friction of 0.50 be used to calculate friction between the
concrete and the underlying soil.
We estimate that settlements of footings designed and constructed as recommended will be less than I inch for the
anticipated load conditions, with differential settlements between comparably loaded footings of/z inch or less.
Most of the settlements should occur essentially as loads are being applied. However, disturbance of the foundation
subgrade during construction could result in larger settlements than predicted.
FLOOR SLAB SUPPORT
Slabs-on-grade should be supported on medium dense or dense native soils or on structural fill prepared as described
in the"Structural Fill"section of this report. We recommend that floor slabs be directly underlain by a minimum 6-
inch thickness of coarse sand and/or gravel containing less than 3 percent fines(by weight). The drainage material
should be placed in one lift and compacted to an unyielding condition.
A synthetic vapor barrier should be used for the control of moisture migration through the slab, particularly where
adhesives are used to anchor carpet or tile to the slab.
10011 Blomberg Street SW, Olympia, WA 98512 8
Phone#:(360)754-4612 Fax#:(360)754-4848
GEOTECHNICAL TESTING LABORATORY
A thin layer of sand may be placed over the vapor barrier and immediately below the slab to protect the liner during
steel and/or concrete placement. The lack of a vapor barrier could result in wet spots on the slab, particularly in
storage areas.
RETAINING WALLS
Retaining walls may be utilized on the sloping
portion of the site to retain fill material or forte • �' ,'� .
controlling surficial sloughing of loose material. =x �� `� y,' ,!4f
The lateral pressures acting on the subgrade and
retaining walls will depend upon the nature and , a
density of the soil behind the wall. It is also
dependent upon the presence or absence of4 '
hydrostatic pressure. If the adjacent exterior wall
space is backfilled with clean granular, well- ,.
drained soil(washed rock), the design active
pressure may be taken as 35 pcf(equivalent fluid jwX �
density). This design value assumes a level
backslope and drained conditions as described '
below.
Retaining walls located on or near the toe of a slope that extends up behind the wall should be designed for a lateral
pressure, which includes the surcharge effects of the steep slope in proximity to the wall. Although not expected at
this site, the following data is provided for planning purposes.
For an irregular or composite slope,the equivalent slope angle may be determined by extending a line upward from
the toe of the wall at an angle of 1 to 1 (Horizontal to Vertical)to a point where the line intersects the ground
surface. The surcharge effects may be modeled by increasing the equivalent fluid pressure for flat ground by the
percentage given in the following table:
SLOPE INCLINATION: EQUIVALENT FLUID PRESSURE
Slope Angle Percent Increase Equivalent Fluid Pressure
Horizontal 0% 35 pcf
3H:1 V 25% 44 pcf
2H:1 V 50% 53 pcf
1 H:1 V 75% 61 pcf
If the walls are greater than 5 feet in height, exclusive of the footing, additional design considerations should be
applied.
Positive drainage, which controls the development of hydrostatic pressure, can be accomplished by placing a zone of
coarse sand and gravel behind the walls. The granular drainage material should contain less than 5 percent fines.
The drainage zone should extend horizontally at least 18 inches from the back of the wall. The drainage zone should
also extend from the base of the wall to within 1 foot of the top of the wall. The drainage zone should be compacted
to approximately 90 percent of the MDD. Over compaction should be avoided as this can lead to excessive lateral
pressures.
10011 Blomberg Street SW, Olympia, WA 98512 9
Phone#: (360)754-4612 Fax#:(360)754-4848
GEOTECBMCAL TESTING LABORATORY
A perforated PVC pipe with a minimum diameter of 4 inches should be placed in the drainage zone along the base of
the wall to direct accumulated water to an appropriate discharge location.
We recommend that a non-woven geotextile filter fabric be placed between the drainage material and the remaining
wall backfill to reduce silt migration into the drainage zone. The infiltration of silt into the drainage zone can, with
time, reduce the permeability of the granular material.
The filter fabric should be placed in such a way that it fully separates the drainage material and the backfill,and
should be extended over the top of the drainage zone.
Lateral loads may be resisted by friction on the bases of footings and as passive pressure on the sides of footings and
the buried portions of the wall. We recommend that an allowable coefficient of friction of 0.50 be used to calculate
friction between the concrete and the underlying soil. Passive pressure may be determined using an allowable
equivalent fluid density of 35 pcf(pounds per cubic foot). Factors of safety have been applied to these values.
RETAINING WALL ALTERNATIVES
Typically, reinforced-earth block wall systems are more cost effective for long-term walls than the other options.
Specific design criteria for these options can be provided at your request by the block manufacturers.
SITE DRAINAGE
Surface water runoff should be controlled by a system of curbs, berms, drainage swales, and/or catch basins and
prevented from flowing on the steep slope. We do not expect any adverse effects on the recharge condition of the
groundwater system. Onsite infiltration of groundwater is feasible; irrigation to lawn areas should be closely
monitored.
LUMTATIONS
We have prepared this report for the use of Mike and Jill Loudin and members of their design team,to use in the
design of a portion of this project. The data used in preparing this report, and this report, should be provided to
prospective contractors for their bidding or estimating purposes only. Our report, conclusions and interpretations
are based on data from others and our site reconnaissance, and should not be construed as a warranty of the
subsurface conditions.
Sufficient consultation with our firm during construction should continue,to confirm that the conditions encountered
are consistent with those indicated by our observations, to provide recommendations for design changes should the
conditions revealed during the work differ from those anticipated,and to evaluate whether earthwork and foundation
installation activities comply with our specifications.
If our analysis and recommendations are followed, we do not anticipate any on site or off site impact from the
proposed construction. It is our conclusion that potential landslide hazards can be overcome so as not to cause harm
to property, public health and safety, or the environment.
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.
10011 Blomberg Street SW,Olympia, WA 98512 10
Phone#: (360)754-4612 Fax#: (360)7544848
GEOTEcHwAL TESTING LABORATORY
If there are any changes in the loads, grades, locations, configurations or types 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.
Respectfully,
GEOTEMUCAL TESTING LAB
7
Harold Parks, L.G., L.E.G.
Senior Engineering Geologist
o
9
d a O�
e HAROLD PARKS
10011 Blomberg Street SW, Olympia, WA 98512 11
Phone#:(360)754-4612 Fax#:(360)754-4848
GEOTECHNICAL TESTING LABORATORY
Filter fabric material in continuous rolls. Use staples or
wire rings to attach fabric to wire.
Wire mesh support fence
for filter fabric
2 ft.
Ground surface
5 ft.
2.5 ft.
6 ft. max.
Bury bottom of filter material in 8
2 in. by 2 in. wood posts. in. by 12 in.trench
Standard or better or equivalent
Wire mesh support fence(to be located on the
downhill side of the filter fabric) 6 in.
Filter fabric material
2 ft.
5 ft.
Provide washed gavel backfill, '/a in.I2 in. 17777
to 3 in. in trench and on both sides of
filter fence fabric on the surface -♦
8 in. min.
Bury bottom of filter material in 8 in. 2 in. by 2 in. by 5 ft. wood posts
by 12 in. trench Standard or better or equivalent
SILT FENCE DETAIL
Not to scale
10011 Blomberg Street SW, Olympia, WA 98512 12
Phone#: (360)754-4612 Fax#:(360)754-4848
GEOTECHNICAL
TESTING LABORATORY
Geotechnical General notes
SOIL PROPERTY SYMBOLS
N: Standard"N'penetration: Blows per foot of a 140 pound hammer falling 30 inches on a 2 inch O.D.split-
spoon.
Q.: Unconfined compressive strength,tons/ftz
Qp: Penetrometer value,unconfined compressive strength,Ibs/ftz
1 imate shearing strength,
i
V: Vane value,u g gth t ,lbs/ft
M: Water content,%
LL: Liquid limit,%
PI: Plasticity index,%
D: Natural dry density,lbs/ft3
WT: Apparent groundwater level at time noted after completion.
DRILLING AND SAMPLING SYMBOLS
SS: Split-Spoon- 1 3/8"I.D., 2"O.D.,except where noted.
ST: Shelby Tube-3"O.D.,except where noted.
AU: Auger Sample.
GB: Grab Sample.
DB: Diamond Bit.
CB: Carbide Bit.
WS: Washed Sample.
RELATIVE DENSITY AND CONSISTENCY CLASSIFICATION
Terms(Non-Cohesive Soils) Standard Penetration Resistance
Very Loose 0-2
Loose 2-4
Slightly Compact 4-8
Medium Dense 8- 16
Dense 16-26
Very Dense Over 26
Terms(Cohesive Soils) Q.-(tonsffil)
Very Soft 0-0.25
Soft 0.25-0.50
Firm(Medium) 0.50- 1.00
Stiff 1.00-2.00
Very Stiff 2.00-4.00
Hard 4.00+
PARTICLE SIZE
Boulders 8 in.+ Coarse Sand 5 mm-0.6 mm Silts 0.074 mm-0.005 mm
Cobbles 8 in.-3 in. Medium Sand 0.6 mm-0.2 nun Clays 0.005 nun&Smaller
Gravel 3 in.-5 mm Fine Sand 0.2 mm-0.074 mm
10011 Blomberg Street SW,Olympia,WA 98512
Phone#:(360)754-4612 Fax#:(360)754-4848
�� ,� .�:•x /). � r .'•��v4`t,YJr•.'�t:4`n•_2+�:Sf14� I
1 � � � .� -,�f��'�:-. •''�::?!r`•'�;' it -�- }(fi��r
jrr !/� 11►. a--y:/yl�� :4,;c
y
Al
M I
1, r
Tv Fw,: r�W.F ;:V4 Ili 11l1I//
•
0 /
P G
O / �
EIGH OR
E ISTI G RAIL R
T AIL R
A
SE T
o
NORTH
SCALE 1" =20'
C.I. =2'
DATUM ASSUMED
THIS IS NOT A SURVEY
0 I I 0 10 20 30 40
220 210 200
PROJECT NAME Date 0 912 3/2 0 0 3 Revislow SpLLEIYd•2D%d
Geotechnical Testing Laboratory LOUDIN SITE Devpned by:LL
Geotechnical Services 1 D01 1 Blomberg St.SW 301 EAST CARBON BLVD. Dra—by LL
Olympia WA SM12 Checked by.LL
QA/QC Services Phow(360)75a-4612 PARCEL 123305100080 Dvge:09-23-03-064
Testing Services Fax:(360)75"640 FIGURE 2