HomeMy WebLinkAboutGeotechnical Engineering Report - GEO Geological Review - 11/12/2008 GeoResources, LLC
Ph 253-896-1011 5007 Pacific Hwy. E., Suite 20
Fx 253-896-2633 Fife, Washington 98424
ovemb 12, 20
Mr. Phil Bennett
PO Box 1863 G,3 ��a,A - 56 " ot�
Belfair, Washington 98528
(360) 277-0643
Geotechnical Engineering Report
Proposed Single Family Residence
xxx North Shore Road
Mason County, Washington
PN: 322245000032
Job: Bennett.NorthShore.GR
INTRODUCTION
This revised report summarizes the results of our geotechnical engineering
services for the proposed residence to be located on the vacant parcel between the
existing residences located at 11001 North Shore Road and 11031 North Shore Road.
GeoResources previously completed a Revised Geotechnical Report for the parcel at
11031 North Shore Road dated February 6, 2008 which was approved by Mason
County on February 22, 2008. The general location of the site is shown on the
attached Site Vicinity Map, Figure 1.
Our understanding of the project is based on discussions with you and your
agent (Mr. Lee Boad), our November 24, 2006 and October 27, 2008 site visits, our
experience on the adjacent parcel and surrounding area, and our discussions with
Mason County. We reviewed the wall designs provided by Mr. Wes Johnson at NIL
Olson & Associates. We understand Mason County has received our Geotechnical
Assessment dated December 26, 2006 for the site and is requesting a
Geotechnical Engineering Report to address the slopes and proposed
development including any proposed walls. Since the time our of original
Geotechnical Assessment, Mason County regulations have changed. This report
will also address the current Mason County Resource Ordinance Title 17.01. The
site is currently undeveloped residential property. We understand that you wish to
construct a new residence with a daylight basement configuration, and lower the top
of the slope on the portion of the site below North Shore road. The proposed
development will include a cast in place concrete retaining wall on both the North
shore road and shoreline walls for the daylight basement, a 15-foot lock block
retaining wall, and a 10-foot rock wall. We understand the lock block wall will be
constructed on the adjacent property and will extend 30 to 40 feet onto the site. A
Site Plan is included as Figure 2a.
SCOPE
The purpose of our services was to evaluate the site as a basis for assessing
potential adverse impacts to and from the slopes located within the site area. The
R ,
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November 12, 2008
Page 2
purpose of our services was to evaluate the surface and subsurface conditions at the site.
We understand that because of the height and inclination of the slopes on the site, an
assessment is being required by Mason County Resource Ordinance Title 17.01.100 to
address geologic hazards at the site. Specifically, our scope of services for the project
included the following:
1. Reviewing available surface and subsurface soil and ground water information,
including USGS Geologic Maps, the Mason County Soil Conservation Service soil
survey, and the Coastal Zone Atlas for Mason County.
2. Visiting the site to conduct a geologic reconnaissance to assess the site's slope,
soil, and surface water conditions.
3. Addressing the appropriate geotechnical regulatory requirements for the
proposed site development.
4. Providing 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.
5. Providing recommendations and design criteria for conventional
foundation and floor slab support, including allowable bearing capacity,
subgrade modulus, lateral resistance values and estimates of settlement.
6. Providing recommendations and design criteria for the design of
conventional subgrade/retaining walls, including backfill and drainage
requirements, lateral design loads, and lateral resistance values.
7. Providing appropriate IBC seismic design parameters for the proposed
structures.
We received a verbal authorization to proceed with our scope of services
from Mr. Phillip Bennett on October 22, 2008. No new subsurface explorations were
completed as part of our current scope of work.
SITE CONDITIONS
Surface Conditions
The site is an undeveloped parcel located west of 11031 NE North Shore Road
and northeast of NE Canyon Drive. The site is roughly rectangular in shape,
encompasses approximately 0.28 acres, and is crossed by NE North Shore Road. The
site has about 160 feet of frontage along NE North Shore Road, and approximately 100
feet below (east) and 100 feet above (west) the roadway. Access to the site is via NE
North Shore Road. The site is bounded by existing residences on the north and
southwest, Hood Canal on the southeast and a green belt/undeveloped tract on
the northwest. The site is currently developed with two driveways, one above
North Shore Road which leads to the existing septic drainfield area and a second
below North Shore Road leading through the proposed building site and to the
shoreline. The lower driveway is currently being used for the excavation and
development on an adjacent property (11031 N Shore Rd). The shoreline is
currently unprotected from shoreline erosion.
The site is located on the shoreline margin of the glacial uplands on a
southeast-facing slope north of Hood Canal, east of Tahuya. The site generally
slopes down from west to east, with North Shore Road situated on a flat bench or
terrace. From the northwest side of North Shore Road the ground surface drops
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November 12, 2008
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into a 1-foot deep ditch and up an 8 foot high road cut. A 10 to 12-foot high cut
slope was observed adjacent to the road cut. The slope above these cuts was
observed to be 40 to 45 percent for 6 vertical feet then decreases inclination to 28
to 30 percent. Near the northwest property line a previously cleared area for the
existing septic drainfield was observed to have a 3 foot fill slope and 2 foot cut
slope. West of the property line the ground surface has 20 to 25 percent slopes.
The upper sloping area east and above North Shore Road is densely vegetated
with the exception of the septic drainfield area. A stockpile of ecology blocks were
observed on the driveway accessing the drainfield. Horsetails were observed near
the toe of the driveway. Total topography relief on the upper portion of the site is
on the order of 25 to 30 feet.
The ground surface on the south side of North Shore Road slopes down
between 80 to 110 percent. The lower driveway was observed to have 20 percent
slopes. Silt fencing (not embedded), loose straw and plastic sheeting were
observed along the driveway. A cut slope taller than 10 feet in height was
observed in the southwest corner of the lower portion of the site below North
Shore Road below the entrance to an adjacent driveway. The northwest portion of
the lower portion of the site has 120 percent slopes with 20 feet of vertical relief.
Below this point the ground surface flattens across the driveway and steepens
again towards the shoreline at 90 to 105 percent with up to 15 feet of relief. The
northeast corner of the site had a greater than 15-foot tall cut slope, which we
understand is part of the excavation for the residential remodel at 11031 North
Shore Road. Total topography relief on the lower portion of the site is on the order
of 40 to 50 feet. We have not been provided a site plan with topography at this
time. However, we have included a site plan as Figure 2a and a parcel map with
landslide hazard areas, buffers, and boundaries as Figure 2b. Existing site
development is sketched on Figure 2c. Photographs of the site in its current
configuration are attached as Figures 2d; through 2d;,,.
No upland water bodies or ravines were observed near the site. The Tahuya
River is located greater than 3,000 feet northwest the site and is separated from
the site by a glacial upland area.We did not observe any evidence of potential mass
soil movement or deep-seated slope instability in the site area at the time of our site visit.
No evidence of significant erosion was observed at the time of our site visit.
Site Soils
A review of the Soil Survey of Mason County (Soil Conservation Survey)
indicates the site soils consist of the Everett gravelly sandy loam (Ek) that form on 15 to
30 percent slopes. The Everett soils are generally derived from gravelly glacial outwash
and is described as well drained. The Everett soils are listed as having a moderate
erosion hazard potential according to the SCS. A copy of the SCS soils map for the site
is included as Figure 3. As previously discussed, we observed no evidence of surficial
erosion at the time of our site visit.
Geologic Conditions
The Geologic Map of the Shelton 1:100,000 Quadrangle, Washington by Robert
L. Logan (2003) maps the soils in the vicinity of the site consisting of Till (Qgt) in the
upper elevations of the site and Advance outwash (Qga) in the lower portions of the site.
These soils may have an overlying thin veneer of recessional outwash deposits. These
glacially derived soils were deposited during the Vashon Stade of the Fraser Glaciation
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approximately 12,000 to 15,000 years ago and are described as a mixture of clay, silt,
sand, gravel and boulders.
The recessional and advance outwash soils consist of a poorly sorted, lightly
stratified mixture of sand and gravel that may contain localized deposits of clay and silt,
that were deposited by meltwater streams emanating from the retreating and advancing
ice mass, respectively. The glacial till consists of a heterogeneous mixture of clay, silt,
sand, and gravel that was deposited at the base of the prehistoric continental glacial ice
mass and was subsequently over-ridden. As such, the glacial till, and advance outwash,
are considered overconsolidated and exhibits high strength and low compressibility
characteristics, where as the recessional outwash deposits are considered normally
consolidated. An excerpt of the above referenced map is included as Figure 4.
We also reviewed the Relative Slope Stability of the Southern Hood Canal Area,
Washington by Smith and Carson dated 1977. This map indicates the site, located on
the flatter upland area north of the Hood Canal, is in a Class I area for slope stability. A
review of the Coastal Zone Atlas for Mason County indicates that the site areas is
situated in an area mapped as "I" for intermediate stability, with localized areas of "U" for
unstable areas southwest of the site. No areas of landslides or landslide debris are
mapped on or within 300 feet of the site. An excerpt of the Coast Zone Atlas map for the
site area is included as Figure 5.
Subsurface Conditions
Near surface soils as observed on the various near vertical cut slopes on
and adjacent to the site generally consist of dense sands and gravel with variable silt,
and cobbles. These soils appear consistent with the Everett soils descriptions. These
soils are interpreted to be older glacial outwash related to the Salmon Springs.
Groundwater Conditions
No groundwater seepage or spring activity was observed in the sloping areas at
or within 300 feet of the site at the site at the time of our site visit or in our adjacent
explorations. Horsetail was observed near the toe of the slope above North Shore
Road. We observed groundwater seepage greater than 500 feet northeast of the
site along North Shore Road.
Landslide Hazard Indicators per Mason County Resource Ordinance 17.01.100
According to the Mason County Resource Ordinance 17.01.100, the purpose of
the landslide hazard assessment is to identify areas that present potential dangers to
public health and safety, to prevent the acceleration of natural geological hazards, to
address off site environmental impacts, and to minimize the risk to the property owner or
adjacent property owners from development activities. The following shall be classified
as Landslide Hazard Areas:
a. Areas with any indications of earth movement such as debris slides,
earthflows, slumps and rock falls.
b. Areas with artificial oversteepened or unengineered slopes, i.e. cuts or fills.
c. Areas with slopes containing soft or potentially liquefiable soils.
d. Areas oversteepened or otherwise unstable as a result of stream incision,
stream bank erosion, and undercutting by wave action.
e. Slopes greater than 15% (8.5 degrees) and having the following:
I. Hillsides intersecting geologic contacts with a relatively permeable
sediment overlying a relatively impermeable sediment or bedrock (e.g.
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November 12, 2008
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sand overlying clay); and
ii. Springs or groundwater seepage.
f. Any area with a slope of forty percent or steeper and with a vertical relief of ten
or more feet except areas composed of consolidated rock. A slope is delineated
by establishing its toe and top and measured by averaging the inclination over at
least ten feet of vertical relief.
In addition, the following information may be used as a guide by the County to
indicate areas that have a higher likelihood of meeting the classification criteria above:
a. The areas identified on the Mason County Soil Survey Map as having slopes
greater than 15%.
b. The areas identified on the Coastal Zone Atlas, Volume 9, of Mason County,
Washington as:
I. Unstable - "U"
ii. Unstable Old Slides - "UOS"
iii. Unstable Recent Slides - "URS"
iv. Intermediate Slopes - "I"
v. Modified Slopes - "M"
c. The areas identified as Class 2, 3, 4, or 5 of the maps: "Relative Slope Stability
of the Southern Hood Canal Area, Washington", by M. Smith and R.J. Carson,
Washington State Department of Natural Resources, Division of Earth
Resources, 1977; and "The Geological Map of North Central Mason County,
Washington", by R.J. Carson, 1976, U.S. Geologic Survey OFR 76-2;
d. Areas mapped as landslide deposits (Map Unit Qls) on the: Geologic map of
the Longbranch 7.5-minute quadrangle, Thurston, Pierce, and Mason Counties,
Washington, by R. L. Logan, T. J. Walsh, and Michael Polenz. 1 sheet, scale
1:24,000, 2003; Geologic map of the Squaxin Island 7.5-minute quadrangle,
Mason and Thurston Counties, Washington, by R. L. Logan, Michael Polenz, T.
J. Walsh, and H. W. Schasse. 1 sheet, scale 1:24,000, 2003; Geologic map of
the Shelton 7.5-minute quadrangle, Mason and Thurston Counties, Washington,
by H. W. Schasse, R. L. Logan, Michael Polenz, and T. J. Walsh. 1 sheet, scale
1:24,000, 2003; and Geologic map of the Summit Lake 7.5-minute quadrangle,
Thurston and Mason Counties, Washington, by R. L. Logan and T. J. Walsh. 42 x
36 in. color sheet, scale 1:24,000, 2004.
Seismic Hazard Areas per Mason County Resource Ordinance 17.01.102
The purpose of the Seismic Hazard Section is to identify areas that present
potential dangers to public health and safety, and to prevent the acceleration of
manmade and natural geological hazards, and to neutralize the risk to the property
owner or adjacent properties from development activities. The following shall be
classified as Seismic Hazard Areas:
1. Areas susceptible to ground failure including the following:
a. Mapped geologic faults until proven inactive;
b. Deep road fills and areas of poorly compacted artificial fill;
c. Areas with artificially steepened slopes (i.e. old gravel pits);
d. Postglacial stream, lake or beach sediments;
e. River deltas;
f. Areas designated as potential Landslide Hazard Areas;
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g. bluff areas;
In addition, the following criteria may be used as a guide by the County to
indicate areas that have a higher likelihood of meeting the classification criteria above:
a. Areas identified on the Coastal Zone Atlas of Washington, Volume 9,
Mason County as Af, Qa1, Qa2, Qvc, Qls, Qos and Qp.
b. Areas identified on the Mason County Soil Survey Map as having
slopes greater than 15 percent.
c. Faults identified on "Map Showing Known or Suspected Faults With
Quaternary Displacement in the Pacific Northwest', A.M. Rogers, T.J.
Walsh, W.J. Kockelman and G.R. Priest, US Geologic Survey, 1996; or
described in "Active Faulting Investigations on the Canyon River Fault,
Southern Olympic Range, Washington", T.J. Walsh and K.G. Neal, U.S.
Geologic Survey, 1997.
Erosion Hazards-per Mason County Resource Ordinance 17.01.104
The purpose of the Erosion Hazard Section is to identify areas that present
potential dangers to public health and safety, and to prevent the acceleration of natural
hazards and to neutralize the risk to the property owner from development
geological p P Y p
activities. The following shall be classified as Erosion Hazard Areas:
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 addition 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")
SLOPE STABILITY METHODOLOGY
The computer program WinStabl (version 3.0 also stated as PCSTABL6) was
used to determine the overall stability of the site in its current configuration and for both
static and seismic conditions in the post-development configuration. Slope failure
surfaces were analyzed using the Simplified Bishop Method, which is a circular failure
force equilibrium method. All calculations were performed by the computer model
WinStabl, which requires user input of the topographic surface, soil strength properties,
groundwater information, and other loads, including seismic and building loads. The
surface profile data was interpreted by the topographic information provided on the Mason
County web site and our observations in the field. The soil parameters used in the
analysis are interpreted, estimated, and/or assumed based on the visual observations,
field and laboratory testing, empirical correlations, and experience with similar soil and
groundwater conditions.
Once the parameters have been determined, the critical failure surfaces and
associated factors of safety for the modeled slope and development conditions can be
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November 12, 2008
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calculated. The critical surface is the surface or plane most likely along which the soil
mass will slide. The factor of safety is the ratio of the sum of moments resisting movement
over the sum of moments driving movements. Accordingly, a slope with a factor of safety
less than 1.0 has more driving forces than resisting forces, while a factor of safety greater
than 1.0 has more resisting forces than driving forces. Industry standard requires that a
site have a factor of safety of 1.5 and 1.1 against failure for static and seismic conditions,
respectively.
Slope Stability Analysis
To analyze the stability of the site, we performed our analysis on the 90 to 120
percent slope observed below North Shore Road. We observed dense sand and gravel
with variable amounts of silt and cobbles. Based on our site observations, provided site
topography, and encountered subsurface soil and groundwater conditions, we
established both dry and saturated unit weight, isotropic strength intercept (cohesion),
and isotropic strength angle (phi angle) for the various soil types.
GeoResources assigned soil unit weight and strength parameters based on our
experience, field explorations accomplished on this site, as well as index laboratory
testing accomplished on this parcels and adjacent properties. Based on our review, we
conclude the assumed values for the various soil types appear to fall within the range of
tabulated values in the literature, and in some instances, these values are conservative.
The following table summarized our assigned soil strength properties.
TABLE 1
ESTIMATED PROPERTIES OF ON-SITE SOILS FOR STABILITY ANALYSIS
Dry Sat. Unit Isotropic Internal
Unit Strength
Soil Type Weight Weight Intercept Strength Angle
(pcf) (pcf) (psf) (degrees)
Dense Sand & Gravel with 125 128 300 34
variable amounts of silt
Retained Structural Fill 132 135 3000 32
(Post-development only)
Cemented Very Dense Sand 133 135 750 36
& Gravel
The site seismic stability conditions were analyzed by applying a horizontal
acceleration equal to one-half of the appropriate peak ground acceleration. Based on
current standard of practice, we used a design peak ground acceleration of 0.15g for the
site.
The following table summarizes soil properties, based on "Geotechnical
Properties of Geologic Materials"by Koloski, Schwarz, and Tubbs, Washington Division
of Geology and Earth Resources Bulletin 78, as presented in Volume 1, ENGINEERING
GEOLOGY IN WASHINGTON. The shallow silty sands are interpreted to be weathered
glacial outwash and stiff silts are interpreted to be weathered over-consolidated glacio-
lacustrine deposits.
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TABLE 2
PROPERTIES OF ON-SITE SOILS FOR STABILITY ANALYSIS
Dry Unit Sat. Unit Isotropic Internal
Weight Weight Strength Strength Angle
Soil Type g g g g
(pcf) (pcf) Intercept (degrees)
(psfGlacial Outwash 115-130 N/A 0-1,000 30-40
Glacio-lacustrine 100-120 N/A 0-3,000 15-35
Using the Simplified Bishop method, we generated several failure surfaces for
three site scenarios listed below in Table 3:
TABLE 3
SLOPE STABILITY TRIALS AND FACTORS OF SAFETY
Trial Development Conditions Safety Factor
Number
Trial 1 (Static) Existing site conditions 1.50
Trial 1 (Seismic) Existing site conditions 1.16
Trial 2 (Static) Building Pad with Retaining Wall Below* 1.63
Trial 2 (Seismic) Building Pad with Retaining Wall Below* 1.27
Trial 3 (Static) Residence with Retaining Wall Below* 1.50
Trial 3 Seismic Residence with Retaining Wall Below* 1.20
*We assume the retaining wall will be either a reinforced fill or a concrete cast-in-place wall.
Graphical output of the WinStabl analysis, indicating the ten most critical failure
planes and corresponding factors of safety for the two post-development models are
included at the end of this report.
In our opinion, provided the recommendations presented in this report are
incorporated into the project design and construction, the proposed development as
following our recommendations will have a negligible effect on slope stability at
the site or on adjacent properties and the risk for such occurrence would be
minimal.
CONCLUSIONS AND RECOMMENDATIONS
Based on the results of our field visit observations, the findings our revised
February 6, 2008 report for the adjacent parcel is consistent with the conditions
observed on the subject parcel. It is also our opinion that although the site meets the
technical definition of a landslide hazard area, the site appears to be in a stable
condition.
Based on the existing topography and our understanding of Mason County
requirements we understand marine setbacks, and property line setbacks will
greatly restrict the development on the portion of the site below North Shore
Road.
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November 12, 2008
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The structures may be supported on new conventional spread footings or floor
slabs bearing on competent native soils or on structural fill placed above these native
soils. We understand that grading at the site will consist of excavating the footings for the
proposed daylight basement residence, site utilities and rockery wall. We
recommend the structure be placed on a deepened foundation to satisfy the IBC
setback requirements. We do not recommend any rockeries to be located within the
zone of influence for any proposed loads or surcharges. Any slow drainage system,
such as an irrigation system, should be placed at least 30 feet back from the
building setback or placed in the gently sloping, portion of the site. Proper surface
drainage and erosion control measures will reduce the risk for future erosion and slope
instability at the site.
Landslide Hazard Classification
According to Mason County Resource Ordinance criteria, portions of the slopes
on the site are classified as a landslide hazard area due to inclination and overall height.
No evidence of past or ongoing earth movement, debris slides, earthflows, slumps or
rockfalls were observed on the site. No slopes with areas containing soft or potentially
liquefiable soils observed. No areas steepened due to undercutting by wave action were
observed. While we did observe areas of 15 percent slopes, we did not observe any
intersecting contacts or seeps on the slope. We did observe areas of greater than 40
percent slopes with more than 10 feet of vertical relief on the adjacent parcel north of the
site and on the upper portion of the site above NE North Shore Road.
The site is in an area identified as "Class 2" for slope stability by the WDNR
"Relative Slope Stability of the Southern Hood Canal Area, Washington" with shoreline
areas south of the site as "Class 3". The site is located in an area mapped by the WDOE
Coastal Zone Atlas as "I" for intermediate and "U" for unstable. We interpret these
identifications to be based on slope inclinations. No evidence of sloughing or deep-
seated movement was observed along the shoreline of the site or within 300 feet of the
site. No historic or recent landslides were shown on maps within 300 feet of the site.
Portions of the site meet the technical criteria of a Landslide Hazard area (slopes
greater than 40 percent with more than 10 vertical feet, mapped "U" for unstable slopes).
In our opinion, the site does not constitute an active landslide hazard area. Control of the
surface drainage at the top of the site slope will likely improve the overall stability on the
site. Proper planning, design, drainage and construction techniques can further reduce
the risk of significant erosion and slope instability.
Buffers-per Mason County Resource Ordinance 17.01.100.D.6
We understand Mason County Resource Ordinance 17.0100.D.6a requires a 50
foot buffer of undisturbed, natural vegetation around a landslide hazard area unless
otherwise stated by a geotechnical engineer. Portions of the slope with 40 percent or
greater and 10 or more vertical feet fit the criteria of a Landslide Hazard area. The
required 50 foot buffer would reduce the building envelope. Provided the
recommendations in the report are followed; we anticipate a reduction or elimination of
the buffer should be allowed, to facilitate the proposed development.
Again, based on our subsurface explorations and our slope stability analysis, it is
our opinion the slope near the proposed residence location appears stable in both its
current and proposed conditions.
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November 12, 2008
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Recommended Setback
The Mason County building department may require a building setback in
accordance with IBC (International Building Code) standard requirements. IBC
section 1805 requires a building setback from slopes that are steeper than 3H:1V
(Horizontal:Vertical) unless evaluated and reduced, and/or a structural setback is
provided, by a licensed geotechnical engineer. The setback distance is calculated
based on the vertical height of the slope. The typical IBC setback from the top of
the slope equals one third the height of the slope while a setback from the toe of
the slope equals one half the height of the slope. IBC does allow the typical
setback to be reduced with a report from a professional engineer.
Based on our understanding of the proposed project, our recent site
observations, and in accordance with IBC guidelines, we recommend a setback
distance of H/3 for slopes greater than 10 feet in height. Where this setback
distance cannot be met, the foundation elements of the structure shall be
extended vertically to meet the horizontal setback distance. Where the foundation
is extended vertically, we recommend that the setback be measured horizontally
from the lower outside edge of the foundation element to the face of the slope.
This structural setback is based on the foundation elements extending to the
dense to very dense native soils.
It may be feasible to reduce the setback. However, in order to consider a
reduced setback, we would need to have more site specific information including
a topographic survey, finish floor elevations, and a foundation plan.
Seismic Hazards- per Mason County Resource Ordinance 17.01.102
Although the site has slopes greater than 15 percent and areas designated a
potential landslide hazard areas based on greater than 40 percent slopes on the site, no
other seismic hazard area indicators are located on the site.
Based on our observation and the subsurface units mapped at the site, we
interpret the structural site conditions to correspond to a seismic Site Class "D" in
accordance with Table 1613.5.2 in the 2006 IBC (International Building Code)
documents. This is based on the likely range of equivalent SPT (Standard Penetration
Test) blow counts for the soil types observed in the site area. These conditions were
assumed to be representative for the conditions based on our experience in the vicinity
of the site.
Liquefaction is a phenomenon where there is a reduction or complete loss of soil
strength due to an increase in pore water pressure. The increase in pore water pressure
is induced by seismic vibrations. Liquefaction mainly affects geologically recent deposits
of loose, fine-grained sands that are below the groundwater table. Based on the density
and coarse-grained nature of the glacial soils observed adjacent to and mapped on the
site, it is our opinion that the risk for liquefaction to occur at this site during an
earthquake is negligible. Provided the design criteria listed below are followed, the
proposed structure will have no greater seismic risk damage than other appropriately
designed structures in the Puget Sound area.
Erosion Hazards- per Mason County Resource Ordinance 17.01.104
The USDA Natural Resource Conservation Service web soil survey Mason
County indicates the soils on the site consist of Everett gravelly sandy loam (Ek).
Although the site does have slopes greater than 15 percent, the site does not meet the
technical criteria of an erosion hazard area. We understand development at the site will
be restricted to the lower, shoreline portion of the lot. Erosion control measures may
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November 12, 2008
Page 11
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.
Erosion Control
Weathering, erosion and the resulting surficial sloughing and shallow land sliding
are natural processes that affect steep slope areas. As noted, no evidence of surficial
raveling or sloughing was observed at the site. To manage and reduce the potential for
these natural processes, we recommend the following:
• No drainage of concentrated surface water or significant sheet flow onto or near
the steep slope area.
• No fill should be placed within the setback area.
• Grading should be limited to providing surface grades that promote surface flows
away from the top of slope to an appropriate discharge location beyond the toe of
the slope.
We recommend that the lot above the slope be graded so that no overbank
concentrated flows can occur. This may entail the placement of a small berm at the
crest of the slope to divert and collect any storm flows away from the steepest portion of
the slope.
Erosion protection measures will need to be in place prior to starting grading
activity on the site. Erosion hazards can be mitigated by applying Best management
Practices (BMP's) outlined in the Washington State Department of Ecology's (DOE)
Stormwater Management Manual for Western Washington. We recommend obtaining a
copy of the WDOE "Vegetation Management:a Guide for Puget Sound Bluff Property
Owners" (93-31) or "Slope Stabilization and Erosion Control Using Vegetation" (DOE
Publication 93-30), available online, for selecting appropriate types of native vegetation
to be used in the permanent revegetation and stabilization of the slope area.
Site Preparation
Areas to be graded should be cleared of deleterious matter including any
existing structures, foundations, abandoned utility lines, debris and vegetation.
The portions of the site still covered with vegetation should be stripped of any
forest duff and organic-laden soils. These materials can be stockpiled and later
used for erosion control. Material that cannot be utilized on site should be
removed from the site.
Where placement of fill material is required, the stripped/exposed subgrade
areas should be compacted to a firm and unyielding surface prior to placement of
any fill. Excavations for debris removal should be backfilled with structural fill
and compacted to the densities described in the "Structural Fill" section of this
report.
Bennett.North Shore.GR
November 12, 2008
Page 12
We recommend that a member of our staff evaluate the exposed subgrade
conditions after removal of vegetation and topsoil stripping is completed and
prior to placement of structural fill. The exposed subgrade soil should be proof-
rolled with heavy rubber-tired equipment during dry weather or probed with a
1/2-inch-diameter steel rod during wet weather conditions.
Any soft, loose or otherwise unsuitable areas delineated during proof-
rolling or probing should be recompacted, if practical, or over-excavated and
replaced with structural fill, based on the recommendations of our site
representative. The areas of old fill material should be evaluated during grading
operations to determine if they need mitigation; recompaction or removal.
Structural Fill
All material placed as fill associated with mass grading, as utility trench
backfill, under building areas, or under roadways 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 95 percent of MDD (maximum dry density as determined in accordance
with ASTM D-1557).
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. 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 US 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 use of well-graded sand and gravel
with less than 5 percent (by weight) passing the US No. 200 sieve based on that
fraction passing the 3/4-inch sieve, such as Gravel Backfill for Walls (9-03.12(2)). If
prolonged dry weather prevails during the earthwork and foundation installation
phase of construction, higher fines content (up to 10 to 12 percent) 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.
Fill placed on slopes that are steeper than 5H:1V should be placed as
structural fill and "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 crests. All slopes should be seeded as soon as practical to facilitate the
development of a protective vegetative cover or otherwise protected.
Suitability of On-Site Materials as Fill
During dry weather construction, any non-organic 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 soil
material is over-optimum in moisture content when excavated, it will be necessary
to aerate or dry the soil prior to placement as structural fill. We generally did not
Bennett.North Shore.GR
November 12, 2008
Page 13
observe the site soils to be excessively moist at the time of our subsurface
exploration program.
The areas of native sand and gravel outwash material are comparable to
"pit run" and may be used for use as structural fill. We recommend that
completed graded-areas be restricted from traffic or protected prior to wet
weather conditions. The graded areas may be protected by paving, placing
asphalt-treated base, a layer of free-draining material such as pit run sand and
gravel or clean crushed rock material containing less than 5 percent fines, or
some combination of the above.
Temporary Excavations
All job site safety issues and precautions are the responsibility of the
contractor providing services/work. The following cut/fill slope guidelines are
provided for planning purposes only. Temporary cut slopes will likely be
necessary during grading operations or utility installation.
All excavations at the site associated with confined spaces, such as utility
trenches and retaining walls, must be completed in accordance with local, state,
or federal requirements. Based on current Washington Industrial Safety and
Health Act (WISHA, WAC 296-155-66401) regulations, the shallow upper soils on
the site would be classified as Type C soils, where as the deeper, granular, dense
soils would be classified as Type B soils.
According to WISHA, for temporary excavations of less than 20 feet in
depth, the side slopes in Type B soils should be laid back at a slope inclination of
1 H:1 V (Horizontal: Vertical) and Type C soils should be laid back at a slope
inclination of 1.5H:1 V or flatter from the toe to the crest of the slope. It should be
recognized that slopes of this nature do ravel and require occasional
maintenance. All exposed slope faces should be covered with a durable
reinforced plastic membrane, jute matting, or other erosion control mats during
construction to prevent slope raveling and rutting during periods of precipitation.
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 where significant raveling or seepage occurs, or if construction
materials will be stockpiled along the slope crest.
As currently configured, there is an approximate 10-foot tall near vertical
cut slope on the upslope side of the proposed building pad. This slope is steeper
than recommended inclinations described above. Where it is not feasible to lay-
back these temporary slopes to conform to WISHA requirements, a temporary or
permanent retaining structure should be considered. Where retaining structures
are greater than 4-feet in height (bottom of footing to top of structure) or have
slopes of greater than 15 percent above them, they should be engineered.
This information is provided solely for the benefit of the owner and other
design consultants, and should not be construed to imply that GeoResources
assumes responsibility for job site safety. It is understood that job site safety is
the sole responsibility of the project contractor.
Foundation Support
Based on the subsurface soil conditions encountered across the site, we
recommend that spread footings for the new residences be founded on dense
Bennett.North Shore.GR
November 12, 2008
Page 14
native sand and gravel soils or on structural fill that extends to suitable native
soils.
The soil at the base of the footing excavations should be disturbed as little
as possible. All loose, soft or unsuitable material should be removed or
recompacted, as appropriate. A representative from our firm should observe the
foundation excavations to determine if suitable bearing surfaces have been
prepared, particularly in the areas where the foundation will be situated on fill
material.
We recommend a minimum width of 2 feet for isolated footings and at least
16 inches for continuous wall footings. All footing elements should be embedded
at least 18 inches below grade for frost protection. Footings founded as
described above can be designed using an allowable soil bearing capacity of
2,500 psf (pounds per square foot) for combined dead and long-term live loads.
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 base of footings and floor
slabs and as passive pressure on the sides of footings. We recommend that an
allowable coefficient of friction of 0.35 be used to calculate friction between the
concrete and the underlying soil. Passive pressure may be determined using an
allowable equivalent fluid density of 300 pcf (pounds per cubic foot). Factors of
safety have been applied to these values.
We estimate that settlements of footings designed and constructed as
recommended will be less than 1 inch, for the anticipated load conditions, with
differential settlements between comparably loaded footings of 1/2 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.
Subgrade/Basement Walls
Based on existing topography, we anticipate the proposed residences may
include a daylight basement configuration.
The lateral pressures acting on subgrade and retaining walls (such as
basement walls) will depend upon the nature and density of the soil behind the
wall. It is also dependent upon the presence or absence of hydrostatic pressure.
If the walls are backfilled with granular well-drained soil, the design active
pressure may be taken as 35 pcf (equivalent fluid density). This design value
assumes a level backslope and drained conditions as described below.
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.
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 nonwoven geotextile
filter fabric be placed between the drainage material and the remaining wall
Bennett.North Shore.GR
November 12, 2008
Page 15
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 such that it fully separates the drainage material
and the backfill, and should extend over the top of the drainage zone.
Lateral loads may be resisted by friction on the base of footings and as
passive pressure on the sides of footings and the buried portion of the wall, as
described in the "Foundation Support" section. We recommend that an allowable
coefficient of friction of 0.35 be used to calculate friction between the concrete
and the underlying soil. Passive pressure may be determined using an allowable
equivalent fluid density of 300 pcf (pounds per cubic foot). Factors of safety have
been applied to these values.
Floor Slab Support
Slabs-on-grade, if constructed, should be supported on the medium dense
native soils or on structural fill prepared as described above. Any areas of old fill
material should be evaluated during grading activity for suitability of structural
support. Areas of significant organic debris should be removed.
We recommend that floor slabs be directly underlain by a capillary break
material with minimum 6-inch thickness of coarse sand, pea gravel, or gravel
containing less than 3 percent fines. The drainage material should be placed in
one lift and compacted to an unyielding condition.
A synthetic vapor barrier is recommended to control moisture migration
through the slabs. This is of particular importance where the foundation elements
are underlain by the silty sediments, or where moisture migration through the slab
is an issue, such as where adhesives are used to anchor carpet or tile to the slab.
A subgrade modulus of 350 kcf (kips per cubic foot) may be used for floor
slab design. We estimate that settlement of the floor slabs designed and
constructed as recommended, will be 1/2 inch or less over a span of 50 feet.
Retaining Walls
As currently proposed, the need for retaining walls on the order of 8 to 12
feet will be required at several locations at the site. Some of these walls are
proposed as rockeries. Along the northeast portion of the site a retaining wall is
proposed by extending the lock block wall from the adjacent property and will be
up to 15 feet in height.
Rockeries
The rockery should be constructed in accordance with the
recommendations provided in this report and the Standard Rock Wall
Construction Guidelines established by the Associated Rockery Contractors
(ARC). All rock used in the rockery construction should meet Washington State
Department of Transportation (WSDOT) requirements presented in their standard
specifications 9-13.7, Rock for Rock Wall. The rockery at the site should be
provided with adequate drainage from behind the rocks. The rockery contractor
should provide you with the appropriate documentation verifying rock quality
prior to bringing any rock onto the site.
The rockery should be constructed against a cut into the medium dense
soils encountered in our subsurface explorations. We recommend installing a
continuous drain behind the rockery. The rockery drain should be tightlined to an
approved point of controlled discharge. Subsurface drains must be laid with a
Bennett.NorthShore.GR
November 12, 2008
Page 16
gradient sufficient to promote positive flow to the point of discharge. All drains
should be provided with cleanouts at easily accessible locations. These
cleanouts should be serviced at least once every year. A recommended typical
Cut Rockery Detail is attached as Figure 6.
Rockeries should be constructed against stable cuts that have a maximum
height of about 6 feet. Where rockeries face fill thicker than 4 feet, the adjacent fill
soils should be reinforced. For rockeries, instead of the wall being mechanically
connected to the reinforced fill, the fill should be wrapped with the geotextile and
the rockery constructed in front of the reinforced soil. In all cases, the backslope
and foreslope should be as close to level as possible, unless the design considers
the site specific conditions.
Rockery wall boulders and chinking material should consist of hard, dense,
sound, and durable rock, free from seams, cracks, and other defects in
accordance with WSDOT Standard Specification 9-13.7(1). Backfill materials for
rockery walls should consist of quarry spalls or shot rock of the same quality.
For frost and erosion protection, as well as sliding resistance, the bottom
course of all rocks should be founded in firm, unyielding soils at least 18 inches
below the adjacent ground surface. The subgrade soil for the bottom course of
rocks should be excavated, as necessary, to ensure full contact between the rock
and soil surfaces.
Rockery boulders should be placed in uniformly decreasing sizes from the
bottom of the rockery to the top, with a battered face no steeper than 1 H:6V. All
boulders should be placed in running bond construction, with no continuous joint
planes in vertical or lateral directions, and each rock should maintain at least two
points of contact with adjacent rocks so that they are keyed together. The
maximum void between adjacent rocks should be less than 6 inches as measured
at the smallest dimension of the void; voids larger than 6 inches should be keyed
with chinking rocks to fill the void.
To prevent the build-up of hydrostatic pressures, a free-draining backfill of
ballast rock (1-to 2-inch quarry spalls) should be provided behind the entire
rockery. This backfill should be placed behind each boulder course and should
extend at least 12 inches behind the rockery. A perforated drain pipe should be
placed along the heel of the rockery and be embedded in pea gravel or washed
rock and should be routed to a catch basin or other suitable discharge point.
Reinforced Soils Wall
A reinforced soil wall consists of structural fill lifts interlayered with
reinforcing grids or strips and supported at the face by a reinforcing material or
segmental (modular) concrete facade. We understand you are planning to use the
Proposed Lock Block Wall Design completed by N.L. Olson & Associates, Inc.
dated October 10, 2007 for the lower wall that will extend onto the site from the
adjacent northern parcel.
The entire area beneath the new reinforced soil zone should be stripped of
all vegetation and organic soils. All subgrade soils should be compacted to a
firm, unyielding condition. No subsurface explorations were actually advanced
within the wall alignment. If unsuitable soils are encountered during excavation,
we recommend that the upper 24 inches of subgrade soils beneath the reinforced
soil zone be overexcavated and replaced with a bearing pad of quarry spalls (1-to
2-inch size). This bearing pad should extend outward at least 24 inches beyond
the wall face.
Bennett.NorthShore.GR
November 12, 2008
Page 17
We anticipate that the fill soils located within the reinforced backfill and
retained backfill zones will consist of the native fine to medium sand. These soils
generally compare to "Sand Borrow" per WSDOT Standard Specifications 9-03.14.
However, the excavated fill soils and/or native soils could be reused as backfill if
they are free of organic matter and are near optimum moisture content at the time
of placement. Existing organic matter, sod, or topsoil stripped from the wall
subgrade would not be suitable for this purpose under any circumstances.
All soils located within the reinforced backfill and retained backfill zones
should be placed and compacted in accordance with our recommendations given
in the Structural Fill section of this report. Specifically, we recommend that all fill
be compacted to a uniform density of at least 90 percent (based on ASTM:D-1557)
and that the upper 2 feet of fill be compacted to at least 95 percent.
The actual wall location may be adjusted to reduce the requirements for
imported fill material as long as the moisture content of the native/fill soils would
allow compaction to the minimum values specified above.
Site Drainage
All ground surfaces, pavements and sidewalks at the site should be sloped away
from structures. The lot should also be carefully graded to ensure positive drainage away
from all structures and property lines. Surface water runoff from the roof area, driveways,
perimeter footing drains, and wall drains, should be collected, tightlined, and conveyed to
an appropriate discharge point.
We recommend that footing drains are installed for the residence, and that the
basement wall (if proposed) have a wall drain as describe above. The roof drain should
not be connected to the footing drain.
LIMITATIONS
We have prepared this letter for use by Mr. Phil Bennett and members of the
design team, for 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 limited site reconnaissance, and should not be
construed as a warranty of the subsurface conditions.
When the design is finalized, we recommend that the design and specifications
be reviewed by our firm to see that our recommendations have been interpreted and
implemented as intended. 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.
Variations in subsurface conditions are possible between the explorations and
may also occur with time. Sufficient monitoring, testing and consultation should be
provided by our firm during construction to confirm that the conditions encountered are
consistent with those indicated by the explorations, to provide recommendations for
design changes should the conditions revealed during the work differ from those antici-
pated, and to evaluate whether earthwork and foundation installation activities comply
with contract plans and specifications.
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, expressed or implied, should be understood.
/ Bennett.North Shore.GR
November 12, 2008
Page 18
Qom ➢
We have appreciated the opportunity to be of service to you on this project. If you
have any additional questions or comments, please do not hesitate to call us at your
earliest convenience.
Respectfully submitted,
GeoRes, LLC
OL"j—,13, ���
Renee M. Hadley, GIT
Staff Geologist
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KEITH SCOTT SCHE B sSro`NAL
Keith S. Schembs, LEG Glen Coad, PE
Principal Principal
WGC:KSS:kss/rmh
Doc ID:Bennett.NorthShore.GR
Attachments: Figure 1 —Site Vicinity Map
Figure 2a—Site Plan
Figure 2b—Parcel Map
Figure 2c—Geologic Cross-section
Figures 2di through 2div—Site Photographs
Figure 3—SCS Soils Map
Figure 4—USGS Geology Map
Figure 5—WA DOE Coastal Atlas
Figure 6—Cut Slope Rockery Detail
Appendix"A"Slope Stability Analysis
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Phone: 253-896-1011
Fax: 253-896-2633 Mason County, Washington
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Proposed Residence
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-W-4 Landslide hazard area Buffer
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GeoResources, LLC Parcel Map
5007 Pacific Highway East, Suite 20 Proposed Residence
Fife, Washington 98424 XXX NE North Shore Road
Phone: 253-896-1011 Mason County, Washington
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Phone: 253-896-1011 Mason County, Washington
Fax: 2537896-2633 DocID: Bennett.NShoreRd.Photo I October 2008 J Figure 2dii
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Phone: 253-896-1011 Mason County, Washington
Fax: 253-896-2633 DocID:Bennett.NShoreRd.Photo October 2008 Fi ure 2diii
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GeoResources, LLC NRCS SCS Soils Map
5007 Pacific Highway East, suite 20 Proposed Residence
Fife, Washington 98424 North Shore Boulevard
Phone: 253-896-1011
Fax: 253-896-2633 Mason County, Washington
File: Bennett.NorthShore.SCS December 2006 Figure 3
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An excerpt from the Geologic Map of the Shelton 1:100,000 Quadrangle,Washington by Robert L. Logan (2003)
Quaternary Sediments
NONCLACIAL DEPOSITS
tZe Alluvium(Iolocene;—Sorted combinations of sill.sand,and gavel
deposited in streambeds and alluvial fans;clasts are generally
rounded and composed of sandstone.derived either from local bed-
rock sources or from reworked Olympic Peninsula(alpine)and Puget
Lowland(continental)glacial deposits;locally may include alpine Qep Alpine drift.prc late Wisconsinan(Pleistocene)—UndiiTeretniated
drift.peat,lacustrine,or landslide deposits;surface is undissecled by till and outwash sand and gravel;gray with local orange weathering:
streams relative to pre-Holocene terrace Surfaces. locally covered with cream-colored weathered loess;consists of
Landslide deposits(Holocenc�Poorly sorted mixturesof locuily mostly ground and end moraine.
Qt$
derived rock and(or)soil emplaced by mass-wasting processes: Alpine outwash,pre—late Wisconsinan(Pleistocene)—Stratified
deposits vary widely in size,composition,and mode of emplacement 5�1sand,gravel.and cobbles;in the Quinault basin.clasts consist of
only the largest landslides are shown:includes rock falls(Schuster sandstone and less-abundant basalt from the Olympic Mountains core
and others,1992)in the southeast Olympic Peninsula that are proba- and peripheral rocks;in streams draining the southern and southeast-
bly seismically induced,and large deep-seated landslides along Hood ere Olympics,clasts consist primarily of Crescent Formadion basalt
Canal(Carson,1976)and along steep-sided inner gorges of river val- with less-abundanl Olympic-cure sandstone;may include peat.silt,
leys in the southern Olympics:smaller shallow deposits such as and clay,and may be capped by weathered loess;clasts are generally
debris flows in steep mountain drainages and rock topples along more rounded than those in till and lack facets and striations;poorly
coastal bluffs,although numerous and dangerous,are too small to to moderately sorted;gray to subtle yellow with wispy orange weath-
show at the map scale. Bring.
Till,late Wisconsinan(Pleistocene}—l)nsoned,unsttatified,highly
compacted mixture of clay,silt.sand,gravel.and boulders deposited
by glacial ice of the Puget lobe;gray;may contain interbedded strati-
fied sand,silt,and gravel;sand-sire fiaction is very angular and con-
lains abundant polycrystalline quartz.which distinguishes this unit
from alpine till;cobbles and boulders are commonly striated and(or)
faceted;although unweathered almost everywhere,may contain cob-
bles or small boulders of deeply weathered granitic rock.
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Not to Scale
GeoResources, LLC USGS Geologic Map
5007 Pacific Highway East, Suite 20 Proposed Residence
Fife, Washington 98424 XXX NE North Shore Road
Phone: 253-896-1011 Mason County, Washington
1 Fax: 253-896-2633 DocID:Bennett.NorthShoreRd.USGS I October 2008 Fiqure 4
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GeoResources, LLC Coastal Zone Atlas
5007 Pacific Highway East, Suite 20 Proposed Residence
XXX NE North Shore Road
Fife,Washington 98424 Mason CountY� Washin ton
Phone: 253-896-1011 9
Fax: 253-896-2633 File: Bennett.NShoreRd.CZA November 2008 Figure 5
GeoResources, LLC
Ph. 253-896-1011 5007 Pacific Hwy. E, Suite 20
Fx. 253-896-2633 Fife, Washington 98424
APPENDIX "A"
Bennett.XXXNorthShoreRd. pre-dev (static) Safety Factors
137.50 ---- -
1 .50
1 .52
1 .53
110.00, 1 .54
1 .55
1 .55
82.5 1 .56
1 .56
1 .57
55.Oa 1.57
27.5
0 27.50 55.00 82.50 110.00 137.50 165.00 1 k.50 220.00
Profile.out
PCSTABL6
by
Purdue University
modified by
Peter J . Bosscher
University of Wisconsin-Madison
--slope stability Analysis--
Simplified 7anbu, Simplified Bishop
or Spencers Method of slices
PROBLEM DESCRIPTION Bennett.XXXNorthshoreRd. pre-dev (static
BOUNDARY COORDINATES
14 Top Boundaries
15 Total Boundaries
Boundary X-Left Y-Left X-Right Y-Right Soil Type
No. (ft) (ft) (ft) (ft) BeloW Bnd
1 0.00 0.00 20.00 5.00 1
2 20.00 5.00 45.00 25.00 1
3 45.00 25.00 55.00 27.00 1
4 55.00 27.00 62.00 35.00 1
5 62.00 35.00 83.00 58.00 1
6 83.00 58.00 95.00 59.00 1
7 95.00 59.00 98.00 65.00 1
8 98.00 65.00 160.00 65.00 1
9 160.00 65.00 162.00 64.00 1
10 162.00 64.00 164.00 65.00 1
11 164.00 65.00 168.00 70.00 1
12 168.00 70.00 180.00 70.00 1
13 180.00 70.00 185.00 80.00 1
14 185.00 80.00 220.00 95.00 1
15 20.00 0.00 220.00 20.00 2
ISOTROPIC SOIL PARAMETERS
2 Type(s) of Soil
Soil Total Saturated Cohesion Friction Pore Pressure Piez.
Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface
No. (pcf) (pcf) (psf) (deg) Param. (psf) No.
1 125.0 128.0 300.0 34.0 0.00 0.0 1
2 133.0 135.0 750.0 36.0 0.00 0.0 1
A Critical Failure Surface searching Method, Using A Random
Technique For Generating Circular surfaces, Has Been specified.
Page 1
Profile.out
100 Trial surfaces Have Been Generated.
10 surfaces Initiate From Each of 10 Points Equally Spaced
Along The Ground Surface Between x = 5.00 ft.
and x = 60.00 ft.
Each surface Terminates Between x = 75.00 ft.
and x = 130.00 ft.
unless Further Limitations were Imposed, The Minimum Elevation
At which A surface Extends Is Y = 0.00 ft.
12.00 ft. Line Segments Define Each Trial Failure surface.
Following Are Displayed The Ten Most Critical Of The Trial
Failure surfaces Examined. They Are ordered - Most Critical
First.
* Safety Factors Are Calculated By The Modified Bishop Method
Failure Surface specified By 12 Coordinate Points
Point x-Surf Y-Surf
No. (ft) (ft)
1 11.11 2.78
2 23.01 4.35
3 34.71 7.01
4 46.11 10.75
5 57.12 15. 53
6 67.63 21.31
7 77. 57 28.05
8 86.83 35.67
9 95.35 44.13
10 103.05 53.33
11 109.86 63.21
12 110.86 65.00
circle Center At x = 0.2 ; Y = 131.5 and Radius, 129.2
1.497 ***
Failure surface specified By 12 Coordinate Points
Point x-Surf Y-Surf
No. (ft) (ft)
1 5.00 1.25
2 16.98 1.87
3 28.83 3.77
4 40.41 6.95
5 51.57 11.35
6 62.19 16.93
7 72.15 23.62
8 81.33 31.35
9 89.62 40.03
10 96.93 49. 55
11 103.17 59.80
12 105.61 65.00
Page 2
Profile.out
Circle Center At x = 5.3 ; Y = 112.3 and Radius, 111.1
1.516 ••
Failure surface Specified By 11 Coordinate Points
Point x-Surf Y-Surf
No. (ft) (ft)
1 11.11 2.78
2 23.08 3.65
3 34.85 6.01
4 46.22 9.82
5 57.04 15.02
6 67.12 21. 53
7 76.31 29.25
8 84.47 38.05
9 91.46 47.80
10 97.18 58.35
11 99.77 65.00
Circle Center At x = 10.1 ; Y = 98.8 and Radius, 96.0
** 1. 528 ***
Failure Surface Specified By 11 coordinate Points
Point x-surf Y-Surf
No. (ft) (ft)
1 23.33 7.67
2 35.25 9.10
3 46.97 11.69
4 58.38 15.41
5 69.37 20.22
6 79.84 26.08
7 89.69 32.93
8 98.83 40.71
9 107.17 49.34
10 114.62 58.74
11 118.66 65.00
Circle Center At x = 14.6 ; Y = 130.4 and Radius, 123.0
*�* 1. 540 ***
Failure surface specified By 12 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 5.00 1.25
2 16.98 0.56
3 28.96 1.34
4 40.75 3.57
5 52.17 7.23
6 63.07 12.26
7 73.27 18.58
8 82.62 26.10
9 90.98 34.71
10 98.23 44.27
Page 3
Profile.out
11 104.26 54.65 `
12 108.68 65.00
Circle Center At X = 16.6 ; Y = 98.6 and Radius, 98.0
1. 546 ......
Failure surface Specified By 9 Coordinate Points
Point X-surf Y-Surf
No. (ft) (ft)
1 29.44 12.56
2 41.34 14.12
3 52.87 17.45
4 63.77 22.48
5 73.78 29.09
6 82.70 37.12
7 90.30 46.41
8 96.42 56.73
9 99.77 65.00
Circle Center At X = 25.0 ; Y = 92.1 and Radius, 79.7
1.555 • ;;*
Failure surface Specified By 10 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 11.11 2.78
2 23.11 3.13
3 34.92 5.22
4 46.30 9.02
5 57.01 14.44
6 66.81 21.37
7 75.50 29.65
8 82.88 39.11
9 88.80 49. 54
10 92.38 58.78
Circle Center At X = 14.7 ; Y = 84.7 and Radius, 82.0
't 1. 556 ..
Failure Surface Specified By 12 Coordinate Points
Point X-surf Y-Surf
No. (ft) (ft)
1 5.00 1.25
2 16.97 2.07
3 28.77 4.28
4 40.23 7.83
5 51.20 12.70
6 61.53 18.80
7 71.08 26.06
8 79.73 34.38
9 87.35 43.65
10 93.85 53.74
11 99.13 64. 51
Page 4
Profile.out
12 99.30 65.00
circle center At x = 3.9 ; Y = 104.5 and Radius, 103.3
** 1. 564 ***
Failure surface specified By 13 coordinate Points
Point x-surf Y-surf
No. (ft) (ft)
1 5.00 1.25
2 17.00 1.19
3 28.95 2.29
4 40.74 4. 52
5 52.26 7.87
6 63.42 12.30
7 74.09 17.78
8 84.19 24.26
9 93.63 31.67
10 102.31 39.96
11 110.16 49.03
12 117.11 58.82
13 120.66 65.00
circle center At x = 11.6 ; Y = 126.4 and Radius, 125.3
** 1.565 ***
Failure surface specified By 9 coordinate Points
Point X-Surf Y-surf
No. (ft) (ft)
1 29.44 12. 56
2 41.15 15.20
3 52.43 19.28
4 63.13 24.73
5 73.06 31.47
6 82.08 39.38
7 90.04 48.36
8 96.83 58.25
9 100.32 65.00
circle center At x = 14.1 ; Y = 107.8 and Radius, 96. 5
*** 1.566 ***
Y A X I S F T
0.00 27.50 55.00 82. 50 110.00 137. 50
X0.00 *---------+---------+---------+---------+---------+
2
-1
*2*
.314
27. 50 528 6
Page 5
Profile.out
31. '
. 592.60
. . .71.
- . 528.0.
A 55.00 +. . . .31. . .
�
. . . . . 48
-. . .5.2.60. .
- . .95.2.6. . . .
- . . . . .413.8 . .
x 82.50 + . . . . . .5.2 63.
- . . . . . . . .1. 8.7
- . . . . . . .45 2.30.87
- . . . . . . . .1.2
- . . . . . . . .4 .1. .83
- . . . . . . . . .4. 5 2.2
1 110.00 + . . . . . . .9. . .11
- . . . . . . . .4. .
. . . . . . . .9. .4
s 137. 50 +
165.00 +
F 192. 50 +
T 220.00 +
Page 6
Bennett.XXXNorth Shore Rd. pre-dev (seismic) Safety Factors
137.50
1.16
1.18
1.19
110.0 1.20
1.20
1.21
82.5G 1.22
1.23
1.23
55.00 1.23
27.5
00 27.50 55.00 82.50 110.00 137.50 165.00 192.50 220.00
Profile.out
PCSTABL6
Purdue University
modified by
Peter J . Bosscher
University of Wisconsin-Madison
--slope Stability Analysis--
simplified 7anbu, Simplified Bishop
or Spencers Method of slices
PROBLEM DESCRIPTION Bennett.XXXNorthshoreRd. pre-dev (seismi
c)
BOUNDARY COORDINATES
14 Top Boundaries
15 Total Boundaries
Boundary X-Left Y-Left X-Right Y-Right Soil Type
No. (ft) (ft) (ft) (ft) Below Bnd
1 0.00 0.00 20.00 5.00 1
2 20.00 5.00 45.00 25.00 1
3 45.00 25.00 55.00 27.00 1
4 55.00 27.00 62.00 35.00 1
5 62.00 35.00 83.00 58.00 1
6 83.00 58.00 95.00 59.00 1
7 95.00 59.00 98.00 65.00 1
8 98.00 65.00 160.00 65.00 1
9 160.00 65.00 162.00 64.00 1
10 162.00 64.00 164.00 65.00 1
11 164.00 65.00 168.00 70.00 1
12 168.00 70.00 180.00 70.00 1
13 180.00 70.00 185.00 80.00 1
14 185.00 80.00 220.00 95.00 1
15 20.00 0.00 220.00 20.00 2
ISOTROPIC SOIL PARAMETERS
2 Type(s) of soil
Soil Total Saturated Cohesion Friction Pore Pressure Piez.
Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface
No. (pcf) (pcf) (psf) (deg) Param. (psf) No.
1 125.0 128.0 300.0 34.0 0.00 0.0 1
2 133.0 135.0 750.0 36.0 0.00 0.0 1
A Horizontal Earthquake Loading Coefficient
Of0.150 Has Been Assigned
Page 1
Profile.out
A vertical Earthquake Loading Coefficient
Of0.000 Has Been Assigned
Cavitation Pressure = 0.0 psf
A Critical Failure surface Searching Method, using A Random
Technique For Generating Circular Surfaces, Has Been specified.
100 Trial Surfaces Have Been Generated.
10 Surfaces Initiate From Each of 10 Points Equally spaced
Along The Ground surface Between x = 5.00 ft.
and x = 60.00 ft.
Each Surface Terminates Between x = 75.00 ft.
and x = 130.00 ft.
unless Further Limitations were Imposed, The Minimum Elevation
At which A Surface Extends Is Y = 0.00 ft.
12.00 ft. Line segments Define Each Trial Failure surface.
Following Are Displayed The Ten Most Critical Of The Trial
Failure surfaces Examined. They Are ordered - Most Critical
First.
Safety Factors Are Calculated By The Modified Bishop Method
Failure surface specified By 12 Coordinate Points
Point x-Surf Y-Surf
No. (ft) (ft)
1 11.11 2.78
2 23.01 4.35
3 34.71 7.01
4 46.11 10.75
5 57.12 15. 53
6 67.63 21.31
7 77. 57 28.05
8 86.83 35.67
9 95.35 44.13
10 103.05 53.33
11 109.86 63.21
12 110.86 65.00
Circle Center At x = 0.2 ; Y = 131. 5 and Radius, 129.2
*** 1.163
Failure Surface Specified By 11 Coordinate Points
Point x-surf Y-surf
No. (ft) . (ft)
1 23.33 7.67
2 35.25 9.10
Page 2
,
3 46.97 11.69 Profile.out
4 58.38 15.41
5 69.37 20.22
6 79.84 26.08
7 89.69 32.93
8 98.83 40.71
9 107.17 49.34
10 114.62 58.74
11 118.66 65.00
Circle Center At X = 14.6 ; Y = 130.4 and Radius, 123.0
1.184 ***
Failure Surface Specified By 12 coordinate Points
Point X-Surf Y-surf
No. (ft) (ft)
1 5.00 1.25
2 16.98 1.87
3 28.83 3.77
4 40.41 6.95
5 51. 57 11.35
6 62.19 16.93
7 72.15 23.62
8 81.33 31.35
9 89.62 40.03
10 96.93 49.55
11 103.17 59.80
12 105.61 65.00
Circle center At X = 5.3 ; Y = 112.3 and Radius, 111.1
1.188 ***
Failure surface specified By 11 Coordinate Points
Point X-surf Y-Surf
No. (ft) (ft)
1 11.11 2.78
2 23.08 3.65
3 34.85 6.01
4 46.22 9.82
5 57.04 15.02
6 67.12 21. 53
7 76.31 29.25
8 84.47 38.05
9 91.46 47.80
10 97.18 58.35
11 99.77 65.00
Circle Center At X = 10.1 ; Y = 98.8 and Radius, 96.0
1.204 ***
Failure surface specified B 13 coordinate Point p y Coo s
Point X-Surf Y-Surf
No. (ft) (ft)
Page 3
Profile.out
1 5.00 1.25
2 17.00 1.19
3 28.95 2.29
4 40.74 4. 52
5 52.26 7.87
6 63.42 12.30
7 74.09 17.78
8 84.19 24.26
9 93.63 31.67
10 102.31 39.96
11 110.16 49.03
12 117.11 58.82
13 120.66 65.00
Circle Center At x = 11.6 ; Y = 126.4 and Radius, 125.3
1.204 *'••
Failure Surface specified By 12 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 5.00 1.25
2 16.98 0. 56
3 28.96 1.34
4 40.75 3.57
5 52.17 7.23
6 63.07 12.26
7 73.27 18. 58
8 82.62 26.10
9 90.98 34.71
10 98.23 44.27
11 104.26 54.65
12 108.68 65.00
Circle Center At x = 16.6 ; Y = 98.6 and Radius, 98.0
*** 1.211 ***
Failure surface specified By 10 Coordinate Points
Point X-Surf Y-surf
No. (ft) (ft)
1 29.44 12. 56
2 41.31 14.37
3 52.95 17.28
4 64.27 21.25
5 75.17 26.27
6 85. 56 32.27
7 95.35 39.22
8 104.45 47.04
9 112.78 55.68
10 120.22 65.00
Circle Center At x = 15.9 ; Y = 140.7 and Radius, 128.9
** 1.216 ***
Failure surface Specified By 12 Coordinate Points
Page 4
Point X-Surf Y-surf Profile.out +
No. (ft) (ft)
1 23.33 7.67
2 34.88 10.92
3 46.26 14.74
4 57.44 19.10
5 68.39 24.01
6 79.08 29.45
7 89. 50 35.41
8 99.62 41.87
9 109.40 48.81
10 118.84 56.23
11 127.90 64.10
12 128.84 65.00
circle center At X = -37.4 ; Y = 245.2 and Radius, 245.2
•••••• 1.227
**
Failure surface specified By 9 coordinate Points
Point X-surf Y-Surf
No. (ft) (ft)
1 29.44 12. 56
2 41.34 14.12
3 52.87 17.45
4 63.77 22.48
5 73.78 29.09
6 82.70 37.12
7 90.30 46.41
8 96.42 56.73
9 99.77 65.00
circle center At X = 25.0 ; Y = 92.1 and Radius, 79.7
1.230 ••**
Failure surface specified By 14 coordinate Points
Point X-surf Y-surf
No. (ft) (ft)
1 5.00 1.25
2 17.00 1.42
3 28.94 2. 57
4 40.75 4.70
5 52.35 7.79
6 63.65 11.82
7 74. 58 16.77
8 85.07 22.60
9 95.04 29.28
10 104.44 36.75
11 113.18 44.96
12 121.22 53.87
13 128. 51 63.41
14 129.53 65.00
circle center At X = 9.0 ; Y = 147.1 and Radius, 145.9
•••••• 1.230
is
Page 5
Profile.out
Y A x I S F T
0.00 27.50 55.00 82.50 110.00 137.50
x0.00 *---------+---------+---------+---------+---------+
3
-1
°3*
.412
27. 50 63. 7
. .418
.653.7. .
. . 18. . .
- .53
A 55.00 +. . . .41.
. . . 28. . .
-. . .5.3 7 .
.218.
- . .56.379. . . . . .
- . . . . .214. . . .
x 82. 50 + . . . .5.3 94. . .
- . . .0. . .71. . .
- . . . . . . .26 3.4. .
- . .0. .7.1.3
. . . . 2 .1. .4
. . .0. . .72.6 3.3
I 110.00 + . . . . . .5. . . .11
. . .0. . .72.
- . . . . . . .85. .2
- . . . . . . .88
5 137. 50 +
165.00 +
F 192. 50 +
T 220.00 +
Page 6
Ben nett.XXXNorth Shore Rd. post-dev (static) w/o House Safety Factors
137.50 1.63
1.66
1 .66
110.0
1.68
1.68
1 .68
82.5a 1.69
1 .69
1.70
55.00 1.70
27.5
00 27.50 55.00 82.50 110.00 137.50 165.00 192.50 220.00
Profile.out
PCSTABL6
by
Purdue University
modified by
Peter J . Bosscher
University of Wisconsin-Madison
--slope stability Analysis--
simplified 7anbu, simplified Bishop
or spencers Method of Slices
PROBLEM DESCRIPTION Bennett.XXXNorthshoreRd. post-dev (stati
C) W/o House
BOUNDARY COORDINATES
17 Top Boundaries
20 Total Boundaries
Boundary X-Left Y-Left X-Right Y-Right Soil Type
No. (ft) (ft) (ft) (ft) BeloW Bnd
1 0.00 0.00 20.00 5.00 1
2 20.00 5.00 45.00 25.00 1
3 45.00 25.00 55.00 32.00 1
4 55.00 32.00 60.00 32.00 1
5 60.00 32.00 60.00 37.00 2
6 60.00 37.00 64.00 37.00 2
7 64.00 37.00 64.00 49.00 2
8 64.00 49.00 75.00 49.00 2
9 75.00 49.00 104.00 49.00 1
10 104.00 49.00 104.00 65.00 1
11 104.00 65.00 160.00 65.00 1
12 160.00 65.00 162.00 64.00 1
13 162.00 64.00 164.00 65.00 1
14 164.00 65.00 168.00 70.00 1
15 168.00 70.00 180.00 70.00 1
16 180.00 70.00 185.00 80.00 1
17 185.00 80.00 220.00 95.00 1
18 60.00 32.00 75.00 32.00 1
19 75.00 32.00 75.00 49.00 1
20 20.00 0.00 220.00 20.00 3
ISOTROPIC SOIL PARAMETERS
3 Type(s) of Soil
Soil Total saturated Cohesion Friction Pore Pressure Piez.
Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface
No. (pcf) (pcf) (psf) (deg) Param. (psf) No.
1 125.0 128.0 300.0 34.0 0.00 0.0 0
2 132.0 135.0 3000.0 32.0 0.00 0.0 0
3 133.0 135.0 750.0 36.0 0.00 0.0 0
Page 1
Profile.out .
A Critical Failure Surface Searching Method, using A Random
Technique For Generating Circular surfaces, Has Been Specified.
100 Trial Surfaces Have Been Generated.
10 surfaces Initiate From Each of 10 Points Equally Spaced
Along The Ground Surface Between x = 5.00 ft.
and x = 60.00 ft.
Each Surface Terminates Between x = 75.00 ft.
and x = 180.00 ft.
unless Further Limitations were Imposed, The Minimum Elevation
At which A Surface Extends Is Y = 0.00 ft.
12.00 ft. Line segments Define Each Trial Failure surface.
Following Are Displayed The Ten Most Critical of The Trial
Failure surfaces Examined. They Are ordered - Most Critical
First.
* Safety Factors Are Calculated By The Modified Bishop Method
Failure surface specified By 10 Coordinate Points
Point x-surf Y-surf
No. (ft) (ft)
1 5.00 1.25
2 16.97 0.43
3 28.93 1.47
4 40. 58 4.35
5 51.64 9.01
6 61.84 15.32
7 70.95 23.14
8 78.73 32.27
9 85.00 42.50
10 87.70 49.00
Circle Center At x = 16.3 ; Y = 77.6 and Radius, 77.2
1.631 ***
Failure surface specified By 9 Coordinate Points
Point x-Surf Y-Surf
No. (ft) (ft)
1 17.22 4.31
2 29.17 3.17
3 41.07 4.74
4 52.32 8.91
5 62.35 15.50
6 70.66 24.15
7 76.83 34.44
8 80. 55 45.85
Page 2
Profile.out
9 80.83 49.00
Circle Center At x = 28.2 ; Y = 56.6 and Radius, 53.4
** 1.658 ***
Failure surface specified By 10 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 11.11 2.78
2 23.06 1.69
3 35.02 2.66
4 46.64 5.67
5 57.57 10.62
6 67. 50 17.37
7 76.12 25.71
8 83.19 35.41
9 88.49 46.17
10 89.32 49.00
Circle Center At x = 23.4 ; Y = 71.6 and Radius, 69.9
1.662 ***
Failure Surface specified By 10 Coordinate Points
Point X-surf Y-Surf
No. (ft) (ft)
1 11.11 2.78
2 23.09 2.04
3 35.04 3.14
4 46.68 6.05
5 57.74 10.71
6 67.95 17.01
7 77.09 24.79
8 84.92 33.88
9 91.28 44.06
10 93.39 49.00
Circle Center At x = 21.9 ; Y = 80.3 and Radius, 78.3
*** 1.677 **
Failure surface specified By 12 Coordinate Points
Point x-Surf Y-Surf
No. (ft) (ft)
1 17.22 4.31
2 29.10 6.00
3 40.79 8.73
4 52.19 12.48
5 63.21 17.21
6 73.78 22.89
7 83.82 29.48
8 93.23 36.92
9 101.96 45.16
10 109.93 54.13
11 117.08 63.76
Page 3
12 117.84 65.00 Profile.out
Circle Center At X = 3.8 ; Y = 140.3 and Radius, 136.7
1.681 ......
Failure Surface Specified By 9 Coordinate Points
Point X-Surf Y-surf
No. (ft) (ft)
1 17.22 4.31
2 29.22 4.08
3 41.11 5.73
4 52. 59 9.20
5 63.40 14.41
6 73.27 21.25
7 81.95 29. 53
8 89.24 39.06
9 94.62 49.00
Circle Center At X = 24.7 ; Y = 80.9 and Radius, 76.9
1.681 *
Failure surface Specified By 13 Coordinate Points
Point X-Surf Y-surf
No. (ft) (ft)
1 5.00 1.25
2 16.98 1.87
3 28.87 3. 52
4 40. 57 6.20
5 51.99 9.89
6 63.04 14. 55
7 73.65 20.16
8 83.74 26.66
9 93.22 34.02
10 102.03 42.17
11 110.09 51.05
12 117.36 60.60
13 120.14 65.00
Circle Center At X = 3.9 ; Y = 139.4 and Radius, 138.1
1.694
Failure surface Specified By 11 Coordinate Points
Point X-surf Y-Surf
No. (ft) (ft)
1 5.00 1.25
2 16.97 2.07
3 28.80 4.08
4 40.38 7.25
5 51.58 11: 56
6 62.29 16.96
7 72.42 23.40
8 81.85 30.82
9 90. 50 39.13
Page 4
Profile.out
10 98.28 48.27
11 98.79 49.00
Circle Center At x = 2.8 ; Y = 121.8 and Radius, 120. 5
*** 1.694 ***
Failure surface Specified By 12 Coordinate Points
Point x-surf Y-surf
No. (ft) (ft)
1 17.22 4.31
2 29.13 5.76
3 40.90 8.14
4 52.43 11.43
5 63.68 15.63
6 74.56 20.69
7 85.01 26.59
8 94.96 33.29
9 104.36 40.75
10 113.14 48.93
11 121.25 57.77
12 126.91 65.00
circle Center At x = 4.7 ; Y = 156.5 and Radius, 152.8
** 1.699 ***
Failure surface specified By 10 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 11.11 2.78
2 23.08 3.65
3 34.89 5.78
4 46.41 9.15
5 57. 51 13.71
6 68.06 19.42
7 77.96 26.20
8 87.09 33.99
9 95.34 42.71
10 100.15 49.00
Circle Center At x = 8.8 ; Y = 116.4 and Radius, 113.6
**� 1.703 ***
Y A X I S F T
0.00 27. 50 55.00 82.50 110.00 137. 50
x0.00 *---------+---------+---------+---------+---------+
1
-3
*7*
.3.
27. 50 AS
1 Page 5
Profile.out
.30.
. .15. .
. .30. .
. . .175.
A 55.00 . . . . . . . . . .
. . . .301. . . . .
E:�:
. . . . .62 .
. . . . . .3012 . .
. . . . . . .758. *
. . . . . . . . .30.12
x 82.50 . . . . . . . . . .75 3. .22
. . . . .9 4.61 31
. . . . . . . . . . 758 4.4
. . . . . . . . . . 9. 0.6
. . . . . . . . . . 75.8
.. . . . . . . . . . . . .9. .
I 110.00 . . . . . . . . . . . . . . . 75
. . . . . . . . . . . .9.
. . . . . . . . . . . . . . . 9755
- . . . . . .9
- . . . . . . . . . . . . . . .
s 137. 50 + . . . . . . . . . . . . . . . .
- . . . . . . . . . . . . . . . .
- . . . . . . . . . . . .
165.00 + . . . .
F 192.50 +
T 220.00 +
Page 6 I
Bennett.XXXNorthShoreRd. post-dev (seismic) w/o House Safety Factors
137.50
1.27
1.27
1.28
110.00 1.28
1.29
1.29
82.5a 1.31
1.31
1.31
55.00 1.31
27.5
0 27.50 55.00 82.50 110.00 137.50 165.00 192.50 220.00
Profile.out
*i PCSTABL6
by
Purdue University
modified by
Peter J . Bosscher
university of Wisconsin-Madison
--slope stability Analysis--
Simplified 7anbu, simplified Bishop
or spencers Method of Slices
PROBLEM DESCRIPTION Bennett.XXXNorthshoreRd. post-dev (seism
ic) w/o House
BOUNDARY COORDINATES
17 Top Boundaries
20 Total Boundaries
Boundary X-Left Y-Left X-Right Y-Right Soil Type
No. (ft) (ft) (ft) (ft) Below Bnd
1 0.00 0.00 20.00 5.00 1
2 20.00 5.00 45.00 25.00 1
3 45.00 25.00 55.00 32.00 1
4 55.00 32.00 60.00 32.00 1
5 60.00 32.00 60.00 37.00 2
6 60.00 37.00 64.00 37.00 2
7 64.00 37.00 64.00 49.00 2
8 64.00 49.00 75.00 49.00 2
9 75.00 49.00 104.00 49.00 1
10 104.00 49.00 104.00 65.00 1
11 104.00 65.00 160.00 65.00 1
12 160.00 65.00 162.00 64.00 1
13 162.00 64.00 164.00 65.00 1
14 164.00 65.00 168.00 70.00 1
15 168.00 70.00 180.00 70.00 1
16 180.00 70.00 185.00 80.00 1
17 185.00 80.00 220.00 95.00 1
18 60.00 32.00 75.00 32.00 1
19 75.00 32.00 75.00 49.00 1
20 20.00 0.00 220.00 20.00 3
ISOTROPIC SOIL PARAMETERS
3 Type(s) of Soil
Soil Total Saturated Cohesion Friction Pore Pressure Piez.
Type Unit wt. Unit wt. Intercept Angle Pressure Constant Surface
No. (pcf) (pcf) (psf) (deg) Param. (psf) No.
1 125.0 128.0 300.0 34.0 0.00 0.0 0
2 132.0 135.0 3000.0 32.0 0.00 0.0 0
3 133.0 135.0 750.0 36.0 0.00 0.0 0
Page 1
Profile.out
A Horizontal Earthquake Loading Coefficient
Of0.150 Has Been Assigned
A vertical Earthquake Loading Coefficient
Of0.000 Has Been Assigned
Cavitation Pressure = 0.0 psf
A Critical Failure surface searching Method, using A Random
Technique For Generating circular surfaces, Has Been specified.
100 Trial surfaces Have Been Generated.
10 surfaces initiate From Each of 10 Points Equally spaced
Along The Ground surface Between x = 5.00 ft.
and x = 60.00 ft.
Each surface Terminates Between x = 75.00 ft.
and x = 180.00 ft.
unless Further Limitations were imposed, The Minimum Elevation
At which A Surface Extends Is Y = 0.00 ft.
12.00 ft. Line segments Define Each Trial Failure surface.
Following Are Displayed The Ten Most Critical Of The Trial
Failure Surfaces Examined. They Are ordered - Most Critical
First.
Safety Factors Are Calculated By The Modified Bishop Method
Failure surface Specified By 12 Coordinate Points
Point x-surf Y-surf
No. (ft) (ft)
1 17.22 4.31
2 29.10 6.00
3 40.79 8.73
4 52.19 12.48
5 63.21 17.21
6 73.78 22.89
7 83.82 29.48
8 93.23 36.92
9 101.96 45.16
10 109.93 54.13
11 117.08 63.76
12 117.84 65.00
Circle Center At x = 3.8 ; Y = 140.3 and Radius, 136.7
°* 1.274 ***
Failure Surface Specified By 12 Coordinate Points
Page 2
Profile.out ,
Point X-Surf Y-Surf
No. (ft) (ft)
1 17.22 4.31
2 29.13 5.76
3 40.90 8.14
4 52.43 11.43
5 63.68 15.63
6 74. 56 20.69
7 85.01 26.59
8 94.96 33.29
9 104.36 40.75
10 113.14 48.93
11 121.25 57.77
12 126.91 65.00
circle center At X = 4.7 ; Y = 156.5 and Radius, 152.8
1.275 ...:*
Failure Surface Specified By 10 coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 5.00 1.25
2 16.97 0.43
3 28.93 1.47
4 40.58 4.35
5 51.64 9.01
6 61.84 15.32
7 70.95 23.14
8 78.73 32.27
9 85.00 42. 50
10 87.70 49.00
circle center At X = 16.3 ; Y = 77.6 and Radius, 77.2
1.283 **
Failure surface specified By 13 coordinate Points
Point X-surf Y-surf
No. (ft) (ft)
1 5.00 1.25
2 16.98 1.87
3 28.87 3. 52
4 40.57 6.20
5 51.99 9.89
6 63.04 14. 55
7 73.65 20.16
8 83.74 26.66
9 93.22 34.02
10 102.03 42.17
11 110.09 51.05
12 117.36 60.60
13 120.14 65.00
circle center At X = 3.9 ; Y = 139.4 and Radius, 138.1
1.284
Page 3
Profile.out
Failure surface specified By 11 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 5.00 1.25
2 16.97 2.07
3 28.80 4.08
4 40.38 7.25
5 51. 58 11.56
6 62.29 16.96
7 72.42 23.40
8 81.85 30.82
9 90. 50 39.13
10 98.28 48.27
11 98.79 49.00
Circle Center At x = 2.8 ; Y = 121.8 and Radius, 120. 5
1.293 ***
Failure Surface specified By 10 Coordinate Points
Point x-surf Y-surf
No. (ft) (ft)
1 11.11 2.78
2 23.08 3.65
3 34.89 5.78
4 46.41 9.15
5 57. 51 13.71
6 68.06 19.42
7 77.96 26.20
8 87.09 33.99
9 95.34 42.71
10 100.15 49.00
Circle Center At x = 8.8 ; Y = 116.4 and Radius, 113.6
1.295 **
Failure surface specified By 9 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 17.22 4.31
2 29.22 4.08
3 41.11 5.73
4 52. 59 9.20
5 63.40 14.41
6 73.27 21.25
7 81.95 29.53
8 89.24 39.06
9 94.62 49.00
Circle Center At x = 24.7 ; Y = 80.9 and Radius, 76.9
��•• 1.306
Failure surface Specified By 10 Coordinate Points
Page 4
Profile.out
Point x-Surf Y-surf
No. (ft) (ft)
1 11.11 2.78
2 23.09 2.04
3 35.04 3.14
4 46.68 6.05
5 57.74 10.71
6 67.95 17.01
7 77.09 24.79
8 84.92 33.88
9 91.28 44.06
10 93.39 49.00
Circle Center At x = 21.9 ; Y = 80.3 and Radius, 78.3
��.. 1.306 ***
Failure surface Specified By 10 Coordinate Points
Point x-Surf Y-Surf
No. (ft) (ft)
1 11.11 2.78
2 23.06 1.69
3 35.02 2.66
4 46.64 5.67
5 57. 57 10.62
6 67.50 17.37
7 76.12 25.71
8 83.19 35.41
9 88.49 46.17
10 89.32 49.00
Circle Center At x = 23.4 ; Y = 71.6 and Radius, 69.9
1.308 ***
Failure surface specified By 9 Coordinate Points
Point x-Surf Y-Surf
No. (ft) (ft)
1 23.33 7.67
2 35.17 9.63
3 46.75 12.79
4 57.94 17.12
5 68.64 22.56
6 78.72 29.07
7 88.09 36.57
8 96.64 44.99
9 99.96 49.00
Circle Center At X = 10.1 ; Y = 124.4 and Radius, 117. 5
* 1.310 it it:c
Y A X I S F T
Page 5
Profile.out
0.00 27. 50 55.00 82. 50 110.00 137. 50
x0.00 *---------+---------+---------+---------+---------+
3
-6
°4*
.6.0
27.50 .31
.86.0 .
. .31.
. .86.0. . *.
. . .321.
A 55.00 . . . . . . . . . .
. . . .863. . . . .
. . . . .41. . .
. . . . . .863.
. . . . . . .415.
. . . . . . . . .8603.
x 82.50 . . . . . . . . . .41 9.
. . . . .2 6073 93
. . . . . . . . . . 415 8.8
. . . . . . . . . . 2. . 6.5
-. . . . . . . . . . . 41.5
-. . . . . . . . . . . . .2. .*
I 110.00 . . . . . . . . . . . . . . 41
- . . . . . . . . . . . .2.
. . . . . . . . . . . . . . . 2411
. . 2
S 137. 50 + . . . . . . . . . . . . . . . .
- . . . . . . . . . . . .
165.00 + . . . .*
F 192.50 +
T 220.00 +
Page 6
Ben nett.XXXNorth Shore Rd. post-dev (static) w/ House Safety Factors
137.50
1 .50
1 .50
1.50
110.00 1.50
1.50
1.51
82.50 1.52
1.54
1.54
55.00 1 .58
27.50
0 27.50 55.00 82.50 110.00 137.50 165.00 1 k.50 220.00
Profile.out
PCSTABL6
by
Purdue university
modified by
Peter J . Bosscher
university of wisconsin-Madison
--Slope Stability Analysis--
simplified 7anbu, simplified Bishop
or spencers Method of slices
PROBLEM DESCRIPTION Bennett.XXXNorthshoreRd. post-dev (stati
c) w/ House
BOUNDARY COORDINATES
17 Top Boundaries
20 Total Boundaries
Boundary X-Left Y-Left X-Right Y-Right Soil Type
No. (ft) (ft) (ft) (ft) Below Bnd
1 0.00 0.00 20.00 5.00 1
2 20.00 5.00 45.00 25.00 1
3 45.00 25.00 55.00 32.00 1
4 55.00 32.00 60.00 32.00 1
5 60.00 32.00 60.00 37.00 2
6 60.00 37.00 64.00 37.00 2
7 64.00 37.00 64.00 49.00 2
8 64.00 49.00 75.00 49.00 2
9 75.00 49.00 104.00 49.00 1
10 104.00 49.00 104.00 65.00 1
11 104.00 65.00 160.00 65.00 1
12 160.00 65.00 162.00 64.00 1
13 162.00 64.00 164.00 65.00 1
14 164.00 65.00 168.00 70.00 1
15 168.00 70.00 180.00 70.00 1
16 180.00 70.00 185.00 80.00 1
17 185.00 80.00 220.00 95.00 1
18 60.00 32.00 75.00 32.00 1
19 75.00 32.00 75.00 49.00 1
20 20.00 0.00 220.00 20.00 3
ISOTROPIC SOIL PARAMETERS
3 Type(s) of soil
Soil Total saturated Cohesion Friction Pore Pressure Piez.
Type Unit wt. Unit Wt. Intercept Angle Pressure Constant Surface
No. (pcf) (pcf) (psf) (deg) Param. (psf) No.
1 125.0 128.0 300.0 34.0 0.00 0.0 0
2 132.0 135.0 3000.0 32.0 0.00 0.0 0
3 133.0 135.0 750.0 36.0 0.00 0.0 0
Page 1
Profile.out
BOUNDARY LOAD(S)
1 Load(s) specified
Load x-Left X-Right Intensity Deflection
No. (ft) (ft) (lb/sqft) (deg)
1 80.00 104.00 1500.0 0.0
NOTE - Intensity Is specified AS A uniformly Distributed
Force Acting on A Horizontally Projected Surface.
A Critical Failure Surface searching Method, using A Random
Technique For Generating Circular surfaces, Has Been specified.
100 Trial surfaces Have Been Generated.
10 Surfaces Initiate From Each of 10 Points Equally spaced
Along The Ground Surface Between x = 5.00 ft.
and x = 60.00 ft.
Each surface Terminates Between X = 75.00 ft.
and x = 180.00 ft.
unless Further Limitations were Imposed, The Minimum Elevation
At which A Surface Extends Is Y = 0.00 ft.
12.00 ft. Line Segments Define Each Trial Failure surface.
Following Are Displayed The Ten Most Critical Of The Trial
Failure surfaces Examined. They Are ordered - Most Critical
First.
* * safety Factors Are Calculated By The Modified Bishop Method
Failure surface Specified By 10 Coordinate Points
Point x-surf Y-surf
No. (ft) (ft)
1 11.11 2.78
2 23.08 3.65
3 34.89 5.78
4 46.41 9.15
5 57. 51 13.71
6 68.06 19.42
7 77.96 26.20
8 87.09 33.99
9 95.34 42.71
10 100.15 49.00
circle Center At X = 8.8 ; Y = 116.4 and Radius, 113.6
1.499 **
Page 2
Profile.out
Failure surface Specified By 11 coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 5.00 1.25
2 16.97 2.07
3 28.80 4.08
4 40.38 7.25
5 51. 58 11. 56
6 62.29 16.96
7 72.42 23.40
8 81.85 30.82
9 90. 50 39.13
10 98.28 48.27
11 98.79 49.00
circle center At X = 2.8 ; Y = 121.8 and Radius, 120.5
*� r 1.499 ***
Failure Surface Specified By 9 coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 17.22 4.31
2 29.22 4.08
3 41.11 5.73
4 52.59 9.20
5 63.40 14.41
6 73.27 21.25
7 81.95 29. 53
8 89.24 39.06
9 94.62 49.00
circle center At X = 24.7 ; Y = 80.9 and Radius, 76.9
1. 501 ***
Failure surface Specified By 9 coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 23.33 7.67
2 35.17 9.63
3 46.75 12.79
4 57.94 17.12
5 68.64 22. 56
6 78.72 29.07
7 88.09 36. 57
8 96.64 44.99
9 99.96 49.00
circle center At X = 10.1 ; Y = 124.4 and Radius, 117. 5
1.505 dr**
Page 3
Profile.out _
Failure surface specified By 12 Coordinate Points
Point x-Surf Y-Surf
No. (ft) (ft)
1 17.22 4.31
2 29.10 6.00
3 40.79 8.73
4 52.19 12.48
5 63.21 17.21
6 73.78 22.89
7 83.82 29.48
8 93.23 36.92
9 101.96 45.16
10 109.93 54.13
11 117.08 63.76
12 117.84 65.00
Circle Center At x = 3.8 ; Y = 140.3 and Radius, 136.7
1. 505 *is is
Failure Surface specified By 10 Coordinate Points
Point x-Surf Y-surf
No. (ft) (ft)
1 11.11 2.78
2 23.09 2.04
3 35.04 3.14
4 46.68 6.05
5 57.74 10.71
6 67.95 17.01
7 77.09 24.79
8 84.92 33.88
9 91.28 44.06
10 93.39 49.00
Circle Center At x = 21.9 ; Y = 80.3 and Radius, 78.3
*** 1. 514 ***
Failure Surface specified By 10 Coordinate Points
Point x-Surf Y-Surf
No. (ft) (ft)
1 5.00 1.25
2 16.97 0.43
3 28.93 1.47
4 40. 58 4.35
5 51.64 9.01
6 61.84 15.32
7 70.95 23.14
8 78.73 32.27
9 85.00 42.50
10 87.70 49.00
Circle Center At x = 16.3 ; Y = 77.6 and Radius, 77.2
1. 523
Page 4