HomeMy WebLinkAboutGeoTech Report Revision for BLD2007-01923 and 01922 - BLD Engineering / Geo-tech Reports - 12/31/2007 e c t o r
E N G I N E E R I N G •-. I N C
309 WASHINGTON STREET NE • OLYMPIA WA 98501• TEL:360 352-2477• FAX 360 352-0179
www.vectorengineeringinc.com
February 15,2008
Mr.Robert D.Fink,AICP
Mason County—Department of Community Development
Mason County Bldg 1
P.O.Box 279
Shelton,WA 98584
E
Subject:Geotechnical Report Acceptance
Permit#s:BLD 2007-01923 BLD 2007-01922
Parcel No.3222-45-000031 or 3222-35-000031
Applicant:NORRIS N&MARY M SUDER
Planner: Chuck McCoy
VEI#:7054-031
Dear Mr.Fink,
The geotechnical report dated May 14,2004 and revised geotechnical report dated December
31,2007,and second revised report dated February 6,2008 prepared by GeoResources, 5113
Pacific Hwy, Suite 1-I, Fife, Washington 98424.2649 for a proposed single family residence
addition and a retaining wall at 11031 NE North Shore Road, Belfair, WA 98528 was
received and reviewed by Vector Engineering,Inc.
No further review by Vector Engineering is necessary.
We have enjoyed working with you on this geotechnical review to support the goals of the
Department of Community Development of Mason County,Washington.We look forward to
cooperating with you on any future project or review.
The buffer reduction request will need to go through the variance process.
The invoice, the geo tech work order, the geotechnical report, revised geotechnical report,
second geotechnical report,and our review are enclosed.
Please feel free to contact me if you have any questions regarding these comments, or if you
feel any features need further discussion or attention.
Sincerely,
Russell W. La Force,P.E.
Design.Engineer
Enc.
Page 1 of 1
X:\7000 Files\7054 Mason County Geotcch Reviews\7054-031 Mason Co(Suder)CR\Admin\Twnsmittal Letters\Geotechnical Report
BLD 2007-01923 Review Acceptance.doc
r e c ■ o r I
i
I N G I N [ E R ► N G I N C {
309 WASHINGTON STREET NE - OLYMPIA WA 98501- TEL:360 352-2477• FAX: 360 352-0179
www.voctorengineeringinc.com
Review of Geotechnical Report
February 15 2008
I
Permit#s:BLD 2007-01923 BLD 2007-01922
Parcel No.3222-45-000031 or 3222-35-000031
Applicant:NORRIS N&MARY M SUDER
Planner: Chuck McCoy
VEI#:7054-031
The geotechnical report dated May 14, 2004 and revised geotechnical report dated December
31,2007,and second revised report dated February 6,2008 prepared by GeoResources, 5113 !
Pacific Hwy, Suite 1-I, Fife, Washington 98424.2649 for a proposed single family residence
addition and a retaining wall at 11031 .NE North Shore Road, Belfair, WA 98528 was
received and reviewed b Vector Engineering, Inc. The Department of Community
Y !� g, p
Development requested the review for the purpose assisting the Department in determining
the amount of potential for landslide activity and the proposed development would not cause
significant adverse impacts or there is adequate geological information available on the area to
determine the impacts of the proposed development and appropriate mitigating measures.The
Department of Community Development reviews all development applications to determine if
they are likely to be in or near a landslide hazard area per Mason County Resource Ordinance
(MCRO),Geologically Hazardous Areas,Landslide Hazard Areas 17.01.100, Seismic Hazard
Areas 17.01.102,and Erosion Hazard Areas 17.01.104 approved December 27,2006.
The geotechnical report states the site has an existing residence on the shore of Hood Canal, a
parking area, a rockery, outside stairs from the parking area, and an existing concrete wall
along the toe of the slope. A site sketch with locations of the existing residence, a parking
area, a rockery, outside stairs from the parking area, and an existing concrete wall was
provided with the report.
A revised geotechnical report was submitted upon the request of the private reviewer as the
report was more than three years olds and there have been changes to the critical areas
ordinance of Mason County.
The second revised geotechnical was submitted upon the request of the private reviewer to
clarify location,retaining wall details and other items.
Findings
1. Areas identified on the Mason County Soil Survey Map as having slopes greater than
15%is one guide used by the County to indicate areas that have a higher likelihood of
meeting the classification criteria for landslide hazard areas. IvMCRO 17.01.100 A.2.a.
Page I of 5
K\7000 Files\7054 Mason County Geotech Reviews\7054-031 Meson_Co(Suder)GR\Admin\Transmittal Letters\Geotechnical Report
BLD 2007-01923 Review.doc
r, • The site slopes south down to Hood Canal at inclinations of 85 to 135 percent.
The vertical relief of the entire slope is approximately 310 feet. The vertical relief
from the highway is 60 feet.
2. A 50-foot buffer of undisturbed natural vegetation is required around the Landslide
Hazard Area or as recommended by the geotechnical engineer. MCRO 17.01.100
D.6.a.
• No buffer or hazard is noted on the site plan.
• The second revised geotechnical report states a buffer would reduce the envelope
of the proposed development, slope appears stable, and to facilitate the proposed
development. At the toe of the slope is a retaining wall and the area is currently `
disturbed. The response is adequate.
3. Based upon the results of the Geotechnical Report or Geological Assessment, the
Director may increase the buffer.MCRO 17.01.100 D.6.b.
i
4. proposed
Development ro d within 300 feet of areas with slopes greater than 40 percent
P P P l�
will require a geotechnical report.MCRO 17.01.100 E.La.
• The existing residence is within 35 feet of the toe of the landslide hazard area.
The addition is within 8 feet of the toe of the landslide hazard area.
5. The geotechnical report shall be prepared by a licensed civil engineer or a licensed I
engineering geologist. MCRO 17.01.100 E.3
• Bradley Biggerstaff, a licensed engineering geologist, and Kurt Groesch, a
licensed civil engineer, prepared the 2004 report. Bradley Biggerstaff and Glen
Coad, a licensed civil engineer, prepared the revised 2007 report and the second
revised report.
6. The report includes a discussion of geologic conditions in the general vicinity,
including soil types, groundwater conditions, upslope geomorphology, location of
upland waterbodies and wetlands, and a history of the landslide activity. MCRO
17.01.100 E.S.(1).
• The revised report states the geology of the site is glacial drift with soils of Everett
gravelly loamy sand deposited during the Vashon Stade of the Fraser Glaciation in
the upper portions of the slope and Salmon Springs sediments in the lower
portions.No groundwater was encountered or observed.It was mentioned than an
adjacent area southwest of the site is mapped as unstable. No evidence of
sloughing or deep-seated movement was observed in the slope above the
residence. There was no mention of upslope geomorphology and upland
waterbodies.
• The second revised report states no upland water bodies or ravines were observed
and no slope instability was observed.The response is adequate.
7. The report is to include a site plan identifying important development or geologic
features.MCRO 17.01.100 E.S.(2).
Page 2 of 5
XA7000 Files\7054 Mason County Geotech Reviews\7054-031 Mason Co(suder)GRWdmin\Transmittal Letters\Geotechnical Report
BLD 2007-01923 Review.doc
L
i
i
• The second revised report includes a site plan showing locations of the existing
residence, a parking area, a rockery, outside stairs from the parking area, and an
existing concrete wall.
8. The report is to include the locations and logs of exploratory holes or probes. MCRO
17.01.100 E.5.(3).
• Three locations were hand augured. The logs are in the report. The locations are
shown on the site sketch.
9. The report is to include a geologic map of the site showing the area of the proposed
development with the boundaries of the hazard, and associated buffers and setbacks
delineated on the map.MCRO 17.01.100 E.5.(4).
• A geologic map of the site showing the area of the proposed development with
boundaries of the hazard, and associated buffers and setbacks needs to be
provided.
• A geologic map of the site showing the area of the proposed development with
boundaries of the hazard,and associated buffers and setbacks was provided in the
second revised report.The response is adequate.
t
10. The report is to include a cross-section at a scale adequately depicting the subsurface
profile.MCRO 17.01.100 E.5.(5).
• A cross-section showing the subsurface profile was provided in the report The
building, road, parking area, existing retaining wall and proposed concrete
bulkhead is also shown on the cross-section
11. The report is to include a description and results of the slope stability analysis. The
analysis should include the Simplified Bishop's Method of Circles. The minimum
static factor of safety is 1.5. The minimum seismic safety factor is 1.1. The quasi-
static analysis coefficient should be 0.15.MCRO 17.01.100 E.5.(6).
• The revised report states on page 6 in the section titled SLOPE STABILITY
METHODOLOGY slope stability was modeled using WinStabl but PCSTABL6
appears to have been used. The revised report also mentions on page 9 in the
section titled STABILITY ANALYSIS,XSTABL was also used.The quasi-static
analysis coefficient used was 0.15.The minimum calculated factors of safety were
estimated to be 1.50 static and 1.18 dynamic.Two soil types were identified.
• The second revised report states the slope stability program used was
WinStabl(PCSTABL6). The response is adequate.
12. The report is to include appropriate restrictions on placement of drainage features, s
septic drainfields and compacted fill and footings,including recommended buffers and
setbacks from the landslide hazard areas.MCRO 17.01.100 E.5.(7). I
• The report includes the restrictions on drainage of concentrated surface water or
significant sheet flow onto the sloped areas; structural fill, including floor slab
support and retaining walls,and setbacks.
Page 3 of 5
XA7000 Files\7054 Mason County Geotech Reviews\7054-031 Mason_Co(Suder)GRWdmin\Trensmittal Letters\Geotechnical Report
BID 2007-01923 Review.doe
s
13. The report is to include recommendations for the preparation of a detailed clearing and
grading plan which specifically identifies vegetation to be removed, a schedule for
vegetation and replanting, and the method of vegetation removal. MCRO 17.01.100
E.S.(8).
i
• The report includes recommendations for clearing and grading. f
14. The report is to include recommendations for the preparation of a detailed temporary
erosion control plan, which identifies the specific mitigating measures to be i
implemented. MCRO 17.01.100 E.S.(9). i
I
• The report does include recommendations for the preparation of a detailed
temporary erosion control plan on page 9 in the section titled EROSION
HAZARD.
15. The report is to include an analysis of both on-site and off-site impacts. MCRO
17.01.100 E.S.(10).
• The revised report includes an analysis of on-site and off-site impacts. The
analysis states the proposed development will not decrease slope stability at the
site or on adjacent properties and the risk for such occurrence would be minimal.
16. The report is to include specifications of final development conditions, such as,
vegetative management, drainage control, and buffer widths. MCRO 17.01.100 E.S.
(10).
• The revised report includes incomplete recommendations for final development
conditions,such as vegetation management,and drainage control.
• The report should include recommendations stressing the need to maintain the
natural vegetative cover on the landslide hazard area and its buffers.
17. The report is to include recommendations for the preparation of structural mitigation
or details of other proposed mitigation.MCRO 17.01.100 E.S.(11).
• The report includes recommendations for mitigation.
18. The report is to include a site map drawn to scale showing the property boundaries,
scale, north arrow, and the location and nature of the proposed development on the
site.MCRO 17.01.100 E.S.(12).
• A site sketch drawn to scale showing the nature of the proposed development
except for the concrete retaining wall in relation to the existing residence, a
parking area, a rockery, outside stairs from the parking area, and an existing
concrete wall is a part of the report.
• A site plan drawn to scale showing the property boundaries, scale, north arrow,
and the location and nature of the proposed development on the site is a part of the
report.
19. If the site is in a Seismic Hazard Area, then the Geological Report shall include a
description of the geology of the site,conclusions and recommendations regarding the
Page 4 of 5
X:\7000 Files\7054 Mason County oeotech Reviews\7054-031 Mason Co(Suder)GR\Admin\Transmittal L.etters\Geotechnieal Report
BLD 2007-01923 Review.doc
i
., effect of geological conditions on the proposed development, and opinions and
recommendations for compensating for the seismic hazards present.MCRO 17.01.102 I
D.3.a.
• The report includes an analysis of the seismic hazard and the site was determined
to be not susceptible to liquefaction.
20.If the site is in an Erosion Hazard Area,then the Geological Report may include a Soil
Erosion and Control Report as an attachment.MCRO 17.01.104 D.3.
• The report mentions that the site does not meet the requirements of an erosion
hazard area.
Conclusions and Recommendations
In the reviewer's opinion, the report,revised report, and second revised report were prepared
by a qualified engineering geologist and qualified civil engineers and does provide sufficient }
information to determine the proposed residence will not decrease slope stability at the site or
on adjacent properties and the risk for such occurrence would be minimal.
It is recommended that the geotechnical report,first revised report,and second revised report
be accepted. No further review by Vector Engineering is necessary.
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.
The conclusions presented in this report are based on Vector Engineering,Inc.' understanding
of the project requirements.Vector Engineering,Inc.warrants that its services were performed
with the level of care and skill ordinarily exercised by members of the same profession
currently practicing in the same locality under similar conditions. No other warranty or
representation,expressed or implied,is included or intended hereunder.
Sincerely,
(Signature) (Date)
y
Russell W.La Force,P.E. Seal:
Design Engineer �Q o
Vector Engineering,Inc. a
309 Washington Street NE 9 42651
Olympia,WA 98501 FcisTS ,
(360) 352-2477 ti; PONAL
EMPIRES
Page 5 of 5
XA7000 Files\7054 Mason County Geotech Reviews\7054-031 Mason Co(Suder)GR\Admin\Transmittal i etters\Geotechnical Report
BLD 2007-01923 Review.doc
t o r
.E N 6 1 N E E 9 1 N 6 1 N f
309 WASHINGTON STREET NE a OLYMPIA WA 98501 , TEL:360 352-2477• FAX: 360 352-0179
www.vectorengineeringinc.com
January 11, 2008
Mr. Glen Coad,PE
GeoResources
5113 Pacific Hwy
Suite 1-I
Fife,Washington 98424-2648
Subject: Geotechnical Report Additional Information Request
Permit#s: BLD 2007-01923 and BLD 2007-01922
Parcel No. 322245-000031 or 3222-35-000031
Applicant: NORRIS N& MARY M SUDER
Planner: Chuck McCoy
VEI#: 7054-031
Dear Mr. Coad
The geotechnical report dated May 14, 2004 and revised geotechnical report dated December
31, 2007 prepared by GeoResources, 5113 Pacific Hwy, Suite 1-I, Fife, Washington
98424.2649 for a proposed single family residence addition and a retaining wall at 11031 NE
North Shore Road, Belfair, WA 98528 was received and reviewed by Vector Engineering,
Inc. The revised report made the review much easier.
It is requested that additional information is needed to complete the review of the revised
report.
The items are: b
� . y 5•
1. Clarification of the property address. The or'
mentions 11301 North Shore Road
but the Mason County website mentio 11031 orth Shore Road.
C'ow r
2. Clarification of the Parcel Number. The report states the parcel is 3222-45-000031 — g�b��
p but the Mason County website has a parcel number of 3222-35-000031 with an
` 6<< V address of 11031 North Shore Road.
3. A better location map is requested which includes a distance from an intersection or
o-s ' other landmark or in the alternative, latitude and longitude coordinates. The location
appears to be where Sections 23 and 24 meet the north shore of Hood Canal, 600 feet
southwest as shown on the Coastal Zone Atlas.
4. A discussion of upslope geomorphology and upland waterbodies. No mention was
found in the revised report. prr"-' •�
Page 1 of 2
K\7000 Files\7054 Mason County Geotech Reviews\7054-031 Mason_Co(Suder)GR\Admin\Transmittal Letters\Geotechnical Report
BLD 2007-01923 Review 2nd Request Letter 080111 a.doc
5. The site plan revised to include a north arrow, proposed concrete retaining wall, all
property boundaries, landslide hazard areas, landslide hazard area boundaries,
landslide hazard area buffers,and landslide hazard area buffer boundaries.
6. If the buffer needs to be reduced, justification for reducing the buffer needs to be
provided.
7. A geologic map of the site showing the area of the proposed development with
boundaries of the hazard, and associated buffers and setbacks needs to be provided.
d,►i / The landslide hazard area and its buffers should be clearly marked.
$. Construction details of the proposed retaining wall. No details were found in the
xOS revised report.
9. Clarification on the computer program used for the slope stability analysis. Three
different ones were mentioned in the revised report.
10. Clarification on the soil type. Alderwood gravelly sandy loam is mentioned on page 2
of the report but Everett gravelly loamy sand is mentioned on page 5.
11. Additional comment on whether or not the entire slope including the slope west of
North Shore Road needs to be analyzed for slope stability as well as just the slope
between North Shore Road and the canal.
Please feel free to contact me if you have any questions regarding these comments, or if you
feel any features need further discussion or attention.
Sincerely,
Russell W. La Force, P.E.
Design Engineer
email Bob Fink,Director,Mason County Planning and Development
Chuck McCoy,Planner,Mason County Planning and Development
Page 2 of 2
XA7000 Files\7054 Mason County Geotech Reviews\7054-031 Mason_Co(Suder)GR\Admin\Transmittal Letters\Geotechnical Report
BLD 2007-01923 Review 2nd Request Letter 080111 a.doc
1 ID PL> 2M7-o t 9. 23
3
���E GeoResources, LLC
Ph. 253-279-1023 JHN _ 3 �0�;� 5113 Pacific Hwy. E., Ste. 1-I
Fx. 253-638-8992 MASON COUNTY, Fife, Washington 98424-2648
O�Mr. Norris Suder December 31, 2007
�,�
13035 151h Avenue NE
Seattle, WA 98125
Ph: 206-367-6251
#vL Revised Geotechnical Report
// a3/ Proposed Residential Remodel
ttSel North Shore Road
Lot 17 Div 14
Mason County, WA
PN:322245000031
JobNo:SuderN.NoShoreRd.RG
INTRODUCTION
This revised report summarizes our site observations, provides our opinion
regarding development of the site and addresses the current Mason County critical area
regulations. The site is located at 11301 North Shore Road along the shoreline of Hood
Canal, approximately 11 miles northwest of Belfair, Washington. The location of the site
is illustrated on the Vicinity Map, Figure 1.
Our services are provided at your request and are based on our site meeting with
you, our experience in the area, and our site observations, and discussions with County
staff. We visited the site on several occasions in March and April of 2004. We
understand that you propose to remodel the single-family residential structure at the site.
We further understand that conventional construction methods will likely be used.
Portions of the lot slope at greater than 40 percent and have a vertical height of
greater than 10 feet. Mason County therefore requires a geotechnical report be
prepared to address slope stability and provide geotechnical recommendations and
design criteria for the proposed single-family residence addition at the site. A site sketch
is include as Figure 2.
The purpose of our services is to address the landslide and erosion hazard issues
at the site per the Mason County SAO (Sensitive Area Ordinance) and provide
geotechnical recommendations and design criteria for the proposed residential site
improvements. Specifically, the scope of services for this project will include the
following:
1. Review the available Critical Area, geologic, hydrogeologic and geotechnical
data for the site area.
2. Conduct a detailed geologic reconnaissance and slope mapping of the site area,
including exposures of the dense, native "hardpan", supplemented by hand
auger test borings at selected representative locations.
3. Conduct a computer generated slope stability analysis using the XSTABL
program.
4. Address the appropriate geotechnical regulatory requirements for the proposed
site development,and slope mitigation measures.
5. Provide geotechnical recommendations for site grading including site
preparation, subgrade preparation, fill placement criteria, suitability of on-site
Suder Residential Remodel
December 31, 2007
Page 2
soils for use as structural fill, temporary and permanent cut and fill slopes, and
drainage and erosion control measures.
6. Provide recommendations and design criteria for foundation and floor slab
support, including allowable bearing capacity, subgrade modulus, lateral
resistance values and estimates of settlement.
7. Provide recommendations and design criteria for design of conventional
subgrade/retaining walls, including backfill and drainage requirements, lateral
design loads, and lateral resistance values, and the possible use or extension of
the existing wall to support the new construction.
8. Provide stormwater runoff control recommendations.
SITE CONDITIONS
SURFACE
The existing home at the site is located above beach level and is currently
accessed by steps descending from a parking area located approximately 6-feet below
the grade of North Shore Road. North Shore Road is situated east of the residence and
dissects the property. Existing residential structures are located on the properties
adjacent to the subject site.
The existing home on the subject property is a waterfront cabin accessed by stairs
that extend down from a parking area and North Shore Road. The shoreline area is
protected by an existing concrete bulkhead. The proposed remodel of the existing
residence and the new addition to be constructed between the rear of the existing
residence and the concrete retaining wall will utilize conventional construction methods.
The new addition will be two stories in height. The existing retaining wall is located at the
base of a steeply descending hillside that is situated between the existing residence and
North Shore Road. The sloping area east of and above North Shore Road is currently
undeveloped.
The ground surface in the proposed residential addition area is generally flat.
The uphill side of the addition area is protected by the existing concrete retaining wall.
The construction details of the existing wall (age, reinforcement, foundation size) are
unknown, and portions of the walls are out of plumb and leaning outwards slightly from
the slope. We understand that this is related to construction, and not movement of the
wall.
The slope area between the wall and the upper parking area is densely vegetated
with mature evergreen trees and sparse underbrush. The trees are vertical in orientation
and do not exhibit "pistol' butt trunks or other evidence indicative of slope instability or
soil creep. The site slope between the residence and parking area ranged between 85
and 100 percent. We measured slopes as steep as 135 percent east of North Shore
Road. The vertical height of the steep slope area above the residence and wall is
approximately 40-feet. No evidence of significant erosion or slope instability were
observed at the site or the adjacent areas. A Cross-Section is included as Figure 3.
SITE SOILS
The Soil Survey for Mason County(USDA Natural Resource Conservation
Service web soil survey) indicates that the site and steep slope area soils consist of
Alderwood gravelly sandy loam (Ab & Ad) that form on 6 to 15 percent and 30 to 45
percent slopes, respectively. The Alderwood soils are generally derived from sandy
glacial outwash and are listed as having "moderate" and "severe" potentials for erosion
Suder Residential Remodel
December 31, 2007
Page 3
hazards, when exposed. A copy of the USDA SCS map for the site is included as Figure
4. As previously discussed, we observed no evidence of surficial erosion at the time of
our site visit.
GEOLOGIC CONDITIONS
The Geologic Map of Washington State, by Eric Schuster, dated 2005, shows
soils in the vicinity of the site to consist of Pleistocene Continental Glacial Drift (Qgd).
The glacial drift soils are described as undifferentiated glacial till and outwash sand and
gravel. Based on our experience in the area, the soils in the upper portion of the slope
were deposited during the Vashon Stade of the Fraser Glaciation, approximately 12,000
to 15,000 years ago. The soils in the lower portion of the slope, exposed along North
Shore Road, are likely older Salmon Springs sediments. The glacial soils in the site area
consists of sand and gravel with variable silt, cobbles and boulders that was deposited
and overridden by the continental ice mass. As such, the undisturbed soils in the site
area are considered overconsolidated and have high strength and low compressibility
characteristics. The near surface recessional outwash deposits consist of a poorly
stratified mixture of sand and gravel that were deposited by meltwater streams and rivers
emanating from the continental ice mass. The surficial soils in the site area have been
weathered by natural processes to a loose to medium dense condition.
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 south of the Hood Canal, is in a Class I area for slope stability.
The shoreline bluff at the site is identified as "S" or Stable by the Department of Ecology
Coastal Zone Atlas. An area of "U" or Unstable shoreline is located just southwest of the
site. A copy of the Coast Zone map for the site area is included as Figure 4.
SUBSURFACE CONDITIONS
As part of our site reconnaissance, we completed a series of hand auger
explorations at selected representative locations across the site. Soil conditions at
specific exploration locations were logged in the field. The conditions encountered in the
individual hand auger explorations were logged in accordance with the Soil Classification
system summarized on Figure 6. Logs of the individual hand auger explorations are
included as Figure 7.
Near surface soils at the site generally consist of dense sands and gravel with
variable silt, cobbles and boulders. The dense sands and gravels are exposed in outcrop
in numerous locations on the uphill side of North Shore Road in the project vicinity.
These soils are interpreted to be older glacial outwash related to the Salmon Springs.
Our site exploration encountered cemented sands and gravels in the crawl space below
the cabin. These soils are likely the older glacial deposits (Salmon Springs) and were in
a very dense and cemented condition. The slope area above the home and retaining
wall is mantled by a thin deposit of topsoil and forest duff. The native sand and gravel
soils below the topsoil in this area were generally in a dense to very dense condition. No
groundwater seepage or spring activity was observed in the sloping areas at or near the
site at the site at the time of our site visit, or in our explorations. Portions of the slope
area below the home, outboard the concrete bulkhead are intermittently submerged,
depending on tidal fluctuations.
+ Suder Residential Remodel
December 31, 2007
Page 4
GEOLOGIC HAZARDS
Landslide Hazard Indicators
According to the Mason County Code, Chapter 8.52.140, landslide hazards are
identified as 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. These areas may be identified by the presence of any of the
following indicators:
(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 fifteen percent (eight and one-half degrees) and having
the following:
(i) Hillsides intersecting geologic contacts with a relatively permeable
sediment overlying a relatively impermeable sediment or bedrock (e.g.
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 above criterion.
(A) The areas identified on the Mason County soil survey map as having slopes
greater than fifteen percent.
(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, 1,977 and "The Geological Map of North Central Mason
County, Washington," by R.J. Carson, 1,976, U.S. Geologic Survey OFR 76-
2.
Seismic Hazards
According to the Mason County Code, Section 8.52,150, "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 man-made and natural geological hazards,
and to neutralize the risk to the property owner or adjacent properties from development
' Suder Residential Remodel
December 31, 2007
Page 5
activities. Types of seismic hazards include: surface faulting; ground shaking;
earthquake-related ground failure and landslides; lateral spreading; liquefaction; lurch
cracks; rockfalls; differential settlement; regional uplift; seiches; and/or tsunamis. These
are defined under seismic hazard areas in Section 8.52.150."
According to Mason County the following are classified as Seismic Hazard Areas:
A. Areas susceptible to ground failure including the following:
1. Areas with geologic faults.
2. Deep road fills and areas of poorly compacted artificial fill.
3. Areas with artificially steepened slopes (i.e., old gravel pits).
4. Postglacial stream, lake or beach sediments.
5. River deltas.
6. Areas designated as potential Landslide Hazard Areas.
7. Bluff areas.
8. Areas underlain by potentially liquefiable soils.
Based on our site evaluation and slope stability analysis, the subject property is
located in an area underlain by very dense consolidated sand and gravel soils, and not
suceptable to design level seismic induced failures.
Liquefaction is a phenomenon where there is a reduction or complete loss of soil
strength due to an increase in water pressure. The increase in pore water pressure is
immediately induced by seismic vibrations. Liquefaction mainly affects geologically
recent deposits of loose, fine-grained sands that are below the groundwater table. The
majority of the outwash soils that underlie the site are in a very dense condition and have
enough fines to make them less likely to liquefy during a seismic event. Therefore, it is
our opinion that the risk for liquefaction to occur at this site during an earthquake is low.
Erosion Hazards
According to the Mason County Code, Section 8.52.160, erosion hazard areas
are described 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 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 fifteen percent or
steeper:
(1) Alderwood gravelly sandy loam ("Ac" and "Ad");
(2) Cloquallum silt loam ("Cd");
(3) Harstine gravelly sandy loam ("Hb");
(4) Kitsap silt loam ("Kc")."
The area of planned development at the site is mapped by the USDA NRCS,
formerly known as the SCS, soil survey for Mason County as Everett gravelly loamy sand
(Ek) soils. Based on this USDA soil classification, according to Mason County, the site is
not classified as an erosion hazard area.
Suder Residential Remodel
December 31, 2007
Page 6
SLOPE STABILITY METHODOLOGY
The computer program WinStabl was used to determine the overall stability of the
site in its current configuration for both static and seismic conditions, and in the post-
development configuration for both static and seismic conditions. Slope failure surfaces
were analyzed using the 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 data was
provided by the topographic site section developed during our evaluation. The soil
parameters used in the analysis are interpreted, estimated, and/or assumed based on our
visual observations, field explorations, empirical correlations, and experience with similar
soil and groundwater conditions in the area.
Once the parameters have been determined, the critical failure surfaces and
associated factors of safety for the modeled slope and development conditions can be
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 85 to 100
percent slope area observed between the residence and North Shore Road. Based on
our site observations, site topography, and the 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
units at the site.
GeoResources assigned soil unit weight and strength parameters based on our
experience, field explorations accomplished in the site area, 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 well within the range
of tabulated values in the literature, and in some instances, the values appear to be
conservative. The following table summarized our assigned soil strength properties.
ESTIMATED PROPERTIES OF ON-SITE SOILS FOR STABILITY ANALYSIS
Dry Unit Sat. Unit Isotropic Internal
Soil Type Weight Weight Strength Strength
(pcf) (pcf) Intercept Angle
(psf) (degrees)
Dense to Very Dense Sand 125 130 250 36
with Silt and Gravel
EOlder Salmon Springs Sand 138 145 750 40
and Gravel
Suder Residential Remodel
December 31, 2007
Page 7
The soil properties utilized were based on the soils observed in the site area and
relevent information provided in "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 dense to very dense sand with silt and gravel is interpreted to be glacial till.
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.
Using the Bishop method, we generated several failure surfaces for the pre- and
post-development conditions using both the static and seismic loading conditions. Our
analyses yielded the following safety factors:
Development Condition Factor Of Safety
Pre Development (Static) 1.50
Pre Development with 1.18
Seismic
Post Development (Static) 1.50
Post Development with 1.18
Seismic
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 as Appendix "A".
Based on the above and provided the recommendations presented in this report
are incorporated into the project design and construction, the proposed development will
not decrease slope stability at the site or on adjacent properties and the risk for such
occurrence would be minimal. In fact, the construction of additional retaining structures
above the addition area with improved drainage controls will improve slope stability at the
site.
CONCLUSIONS
GENERAL
Based on a review of the available geologic information and our site
reconnaissance, it is our opinion that the site is currently stable under the existing
conditions. The proposed addition will provide additional slope stabilization measures
and drainage controls. Proper retainage of the upslope area and improved surface
drainage and erosion control measures will reduce the risk for erosion and slope
instability at the site. The greatest risk of erosion and/or slope instability is during
construction. Appropriate erosion control measures will be installed to mitigate this risk.
We understand that grading at the site will be minimal, and will consist primarily of
excavating for the footings for the residential addition and new retaining structures for the
proposed addition, and any new site utilities and landscaping. Based on our
understanding of the project, it is our opinion that the site soils will provide adequate
support for the structure provided they are prepared in accordance with the standards of
practice for the Puget Sound area and the recommendations provided herein.
Suder Residential Remodel
December 31, 2007
Page 8
Geotechnical recommendations and design criteria for the proposed residential addition
are provided below.
Landslide Hazard
Based on our site observations, explorations and review of the available
published information, no evidence of past or ongoing earth movement, or landslide
activity was identified. No significant areas of fill material or unretained over-steepened
slopes were observed, nor were slopes with areas containing soft or potentially
liquefiable soils observed at the site. We did not observe areas oversteepened or
unstable soils as a result of stream incision, stream bank erosion, or undercutting by
wave action. The shoreline area is protected with a concrete bulkhead. While we did
observe areas of 15 percent slopes, we did not observe intersecting contacts or seeps
on the slope east of the building site. We also observed areas of greater than 40
percent slopes with more than 10 feet of vertical relief at the site. A portion of that slope
area is retained by a concrete retaining wall. No evidence of erosion or slope instability
was observed at the site or the adjacent areas. The site area is located in an area of
Class I and Class II slope stability because of the steep slope areas by the "Relative
Slope Stability of the Southern Hood Canal Area, Washington."
Although portions of the site meet the technical criteria of a Landslide Hazard
area (slope greater than 40 percent with more than 10 vertical feet, Class II for slope
stability on the slope area), it is our opinion that the site soils are in a stable condition
based on our site observations and slope stability analysis.
The construction of the residential addition at the site will not have any adverse
impact on the stability of the slopes. Because the proposed addition area is currently
occupied by the existing shed roof addition and patio, no significant increase in
impervious area or storm water runoff is anticipated. Significant slope movement typically
occurs during or following significant or extended periods of rainfall/precipitation.
Although proper planning, design, drainage and construction techniques can reduce the
risk of significant erosion and slope instability, there is an inherent risk of instability
associated with steep shoreline sites.
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. Based on the subsurface units mapped at the site, we interpret the structural
site conditions to correspond to a seismic Soil Profile type Sc, for Very Dense Soil, as
defined by Table 16-J (UBC) and Site Class "C" in accordance with Table 1615.1.1 in the
2003 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.
Based on our review of the subsurface conditions in the site area, we conclude that
the site soils are not susceptible to liquefaction. The near-surface soils are generally in a
medium dense to very dense condition and the static water table is located below the site.
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.
Liquefaction is a phenomenon where there is a reduction or complete loss of soil
strength due to an increase in 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
r Suder Residential Remodel
December 31, 2007
Page 9
and coarse-grained nature of the glacially derived soils observed on the site, and the lack
of a groundwater table, it is our opinion that the risk for liquefaction to occur at this site
during an earthquake is negligible.
Erosion Hazard
A review of the SCS soil survey for Mason County indicates the site soils consist of
Everett gravelly sandy loam (Ek) and are listed as having a "moderate to severe" potential
for erosion when exposed. The removal of vegetation and grading activity will result in an
increased risk for erosion. We recommend that temporary and permanent erosion control
measures be installed and maintained during and following construction, until permanent
erosion control measures or landscaping is in place.
We recommend that any disturbed areas be re-vegetated as soon as practical with
native vegetation, landscaping or other slope stabilizing materials. During wet weather
conditions, erosion control measures may include but should not be limited to berms and
swales to channel surface water runoff, and ground cover/protection in exposed or
disturbed areas. Temporary ground cover/protection such as jute matting, excelsior
matting, wood chips or clear plastic sheeting should be used during wet weather conditions
until permanent erosion protection is established. Silt fences should be utilized where
appropriate.
Stability Analysis
Based on our evaluation and XSTABL analysis, it is our opinion that the site soils
are generally stable under the existing conditions. It is also our opinion that the
proposed residential remodel and addition will not adversely impact the stability of the
site. This report contains the results of our stability analysis, as well as slope mitigation
measures by vertically extending the existing retaining wall to protect the proposed
addition area. The Vashon soils and Salmon Springs deposits at the site are in a dense
to very dense condition. Surficial soils at the site have been disturbed through natural
weathering processes and are presently in a loose to medium dense condition. The very
dense site soils have a moderate erosion hazard if undisturbed, especially in the heavily
vegetated area. However, the loose to medium dense surficial soils mantling the slope
will likely represent a severe erosion hazard when disturbed — under construction.
Appropriate erosion control measures will mitigate this risk.
With respect to more substantial deep-seated failure modes, our analysis
indicates the static factor of safety for the existing slope condition is 1.50. We also
modeled the existing slope in a seismic event using a pseudo-static horizontal
acceleration coefficient equal to 0.15 g. For this case, a seismic factor of safety equal to
1.18 was computed. The factors of safety did not change with the proposed addition at
the site.
These factors of safety reflect an acceptable stability regime at the site. A Factor
of Safety above 1.5 is considered acceptable for structures using static analyses. The
2001 earthquake event in the Puget Sound area was a 6.8 seismic event. This seismic
event effectively provided an in-situ test of slope stability during a design level seismic
event. Anecdotal information indicates no evidence of slope instability was observed in
the slope area or the proposed building site as a result of the 2001 Nisqually event. The
reported seismic factors of safety for both the existing and proposed addition are above
unity.
Suder Residential Remodel
December 31, 2007
Page 10
EARTHWORK
Site Preparation
Based on our document review and our discussions with you, additional grading at
the site will be minimal and generally consist of the excavation of the foundation for the
addition. We expect that grading at the site can be accomplished with conventional earth
moving equipment. The site soils generally consist of sand and gravel with variable silt and
cobble content. These soils may be used as structural fill during dry and moderate wet
weather conditions.
Structural Fill
No additional significant earthwork is expected at the site. The following
recommendations are provided in the event that plans change. All fill material used to
achieve design grades at the site should be placed as structural fill. The structural fill
should be placed in horizontal lifts of appropriate thickness to allow adequate and uniform
compaction of each lift. Fill placed in the building and pavement areas should be
compacted to a firm and unyielding surface.
The appropriate lift thickness will depend on the fill characteristics and compaction
equipment used. We recommend that the appropriate lift thickness be evaluated by our
field representative during construction. For planning purposes, we recommend a
maximum loose-lift thickness of 12 inches. We recommend that our representative be
present during site grading activities to observe the work and perform field density tests.
The suitability of material for use as structural fill will depend on the gradation and
moisture content of the soil. As the amount of fines (material passing No. 200 sieve)
increases, soil becomes increasingly sensitive to small changes in moisture content and
adequate compaction becomes more difficult to achieve. If it is necessary to import
structural fill material to the site, we recommend that fill material consist of well-graded
sand and gravel with less than 5 percent passing the No. 200 sieve based on that fraction
passing the 3/4-inch sieve. During prolonged dry weather conditions, a somewhat higher
(up to 10 to 12 percent) fines content will be acceptable.
Material placed for structural fill should be free of debris, organic matter, trash and
cobbles greater than 6 inches in diameter. Particle sizes larger than 3 inches should be
excluded from the top 1-foot of fill. The moisture content of the fill material should be
adjusted as necessary for proper compaction.
Suitability of On-Site Materials as Fill
During dry weather construction, any nonorganic on-site soil may be considered for
use as structural fill, provided it meets the criteria described above in the structural fill
section and can be compacted as recommended. If the material is over the optimum
moisture content (typically 2 to 4 percent) when excavated, it will be necessary to aerate or
dry the soil prior to placement as structural fill.
The workability of material for use as structural fill will depend on the gradation and
moisture content of the soil. As the amount of fines increases, soil becomes increasingly
more sensitive to small changes in moisture content and adequate compaction becomes
more difficult or impossible to achieve.
In general, the soils observed at the site consist of sand and gravel with variable silt
and cobble content. These materials are suitable for use as structural fill during dry and
moderately wet conditions. It may be necessary to moisture condition these soils prior to
use as structural fill, particularly during dry weather conditions.
Suder Residential Remodel
December 31, 2007
Page 11
CUT AND FILL SLOPES
Temporary cut slopes (foundation and utility excavations) may be necessary during
grading operations. As a general guide, temporary slopes of 1.5 to 1 (horizontal to vertical)
or flatter may be used for temporary cuts in the upper 3 to 5 feet of medium dense to
dense soils. Temporary slopes of 1 to 1 or flatter may be used in the unweathered dense
to very dense sands and gravels or till. These guidelines assume that all surface loads are
kept at a minimum distance of at least one half the depth of the cut away from the top of
the slope and that significant seepage is not present on the slope face. Flatter cut slopes
will be necessary if/where significant soil moisture or seepage occurs.
In the event that permanent cut and fill slopes are required, we recommend a
maximum of 2 to 1 slope. Where 2 to 1 slopes are not feasible, retaining structures should
be considered. Fill placed on slopes that are steeper than 5 to 1 should be "keyed" into the
undisturbed native soils by cutting a series of horizontal benches. The benches should be
11/2 times the width of equipment used for grading and a maximum of 3 feet in height.
Subsurface drainage may be required in seepage areas. Surface drainage should be
directed away from all slope faces. Some minor raveling may occur with time. All slopes
should be seeded as soon as practical to facilitate the development of a protective
vegetative cover or otherwise protected.
BUILDING FOUNDATIONS
Conventional spread footings are recommended for support of the residential
addition. For the new addition bearing on medium dense native soil, we recommend an
allowable soil bearing pressure of 2,000 pounds per square foot (psf) for combined dead
and long-term live loads, exclusive of the weight of the footing and any overlying backfill. A
higher bearing pressure of 3,000 psf may be used if the footings extend to the dense to
very dense soils encountered below 3-feet in the addition area. These values may be
increased by one-third for transient loads such as those induced by seismic events or wind
loadings.
We recommend a minimum width of 18 inches for isolated footings and 16 inches
for continuous wall footings. All exterior footing elements should be embedded at least
18 inches below the lowest adjacent finished grade. We recommend that any disturbed
soils in the footing excavations be removed, or if practical, recompacted prior to concrete
placement
We estimate that settlements of footings designed and constructed as
recommended will be less than 1/2 inch, with differential settlements between comparably
loaded footings of 1/2 inch or less. These settlements will occur essentially as loads are
applied. Disturbance of the foundation subgrade during construction could result in larger
settlements than predicted.
FLOOR SLAB SUPPORT
Slabs-on-grade should be supported on dense native soil or on structural fill
prepared as recommended. We recommend that floor slabs at the site be underlain by a
6-inch thickness of uniformly graded gravel or sand containing no more than 3 percent
fines to provide a capillary break. The capillary break material should be placed in one lift
and compacted to a firm and unyielding surface. The capillary break material should be
connected to a suitable drain outlet to provide an exit for any accumulated seepage.
Where the native soils meet this criteria, they are considered suitable for use as the
capillary break.
A vapor barrier, such as a polyethylene liner is recommended where the native or
fill soils contain greater than 3 percent fines. A thin layer of"clean" sand may be placed
Suder Residential Remodel
December 31, 2007
Page 12
over the vapor barrier and immediately below the slab to protect the polyethylene liner
during steel and/or concrete placement.
A subgrade modulus of 250 kcf (kips per cubic foot) may be used for design. We
estimate that settlement of the floor slabs designed and constructed as recommended, will
be 1/2 inch or less over a span of 50 feet.
LATERAL RESISTANCE
Lateral loads may be resisted by friction on the base of footings and floor slab and
as passive pressure on the sides of footings. We recommend a coefficient of friction of
0.65 be used to calculate friction between the concrete and very dense soil. Passive
pressure may be determined using an equivalent fluid weight of 300 pcf (pounds per cubic
foot) above the water table, and 160 pcf for saturated soils. This assumes that structural fill
is placed against the sides of the footings and that the top of the fill is confined by either a
concrete floor slab or pavement. A safety factor of 1.5 is conventionally applied to these
values.
RETAINING BASEMENT WALL
Because of the uncertainties regarding the construction of the existing concrete wall
at the site, we do not recommend this wall be relied upon to protect the new addition. In
addition, even though adequate factors of safety were indicated for deep-seated failures at
the site, there is a risk of surficial sloughing in the slope area above the residence.
Because of the steep slope above the addition area, and the presence of large trees on the
slope, we recommend that a new retaining wall be constructed against the toe of slope and
extend above the existing top of wall by a minimum of 5-feet.The wall extension would
provide a catchment area to protect the addition from surficial sloughing type failures. The
existing wall can remain in place and serve as a portion of the back form for the new wall.
In addition, we recommend that no penetrations or openings (windows or doors) be
constructed in the addition on the side of the structure facing the slope. We also
recommend that the trees located above the residence be removed (stumped) or trimmed
to reduce the potential for damage in the event of a shallow failure.
The proposed retaining wall can be supported on conventional shallow footings
founded on medium dense native soils or structural fill, if properly prepared. Footings
bearing on undisturbed native soils or structural fill as described above can be designed
using an average allowable bearing value of 2,000 psf with a maximum toe pressure of
3,000 psf. Footings extended to bear on the dense to very dense soils may be designed to
exert an average allowable bearing pressure of 3,000 psf, with a maximum toe pressure of
4,000 psf.
Lateral loads on conventional retaining structures founded as described above may
be resisted by friction on the base of the wall footings and as passive pressure on the sides
of footings. We recommend using an ultimate coefficient of friction of 0.65 to calculate
friction between the concrete and dense native soils or on structural fill. Passive pressure
may be determined using an equivalent fluid weight of 300 pcf. This assumes that
structural fill is placed against the sides of the footings. A safety factor of 1.5 should be
applied to these values, for sliding and overturning.
The lateral active soil pressures acting on reinforced concrete retaining walls
depend on the nature, density and configuration of the soil behind the wall. We
recommend that portions of walls supporting horizontal backfill be designed using an
equivalent fluid density of 35 pcf for a level back-slope behind the wall. For the condition of
the steep slope above the wall (85 per cent), we recommend a lateral design pressure
Suder Residential Remodel
December 31, 2007
Page 13
equal to 65 pcf be used. The recommended pressure does not include the effects of sur-
charges from surface loads.
Adequate drainage behind any retaining structure or subgrade wall is imperative.
The actual condition of the drainage system for the existing wall is not known. To promote
drainage through the existing wall, we recommend the wall be penetrated with small
diameter weep holes at the base of the existing wall on a horizontal spacing no greater
than 10-feet on center. Seepage from the weep holes should be collected and manifolded
to an appropriate discharge point. If the existing wall is utilized as a back form for the new
wall, we recommend the space between the walls include a drainage medium, such as
Miradrain or other proprietary drainage material. If the new wall is set forward of the
existing wall, in addition to the weep holes, we recommend that a drainage system
consisting of a minimum 12 inches of clean sand and/or gravel with less than 3 percent
fines be placed along the back of the wall. The drainage collector system consisting of fl-
inch perforated PVC pipe should be installed between the two walls to provide an outlet for
any accumulated water. The drainage material should be capped at the ground surface
with 1-foot of relatively impermeable soil or otherwise sealed.
SITE DRAINAGE
All ground surfaces, pavements and sidewalks at the site should be sloped away
from structure. Surface water runoff should be controlled by a system of sloping surfaces,
curbs, berms, drainage swales, and/or catch basins, and conveyed to an appropriate
discharge point at the shoreline. Drains should be provided behind all retaining walls.
We recommend that roof runoff at the site be collected and discharged to the
Hood Canal. No significant increase in hard surface area is anticipated because the
addition area is currently occupied by an existing patio and shed roof addition. Driveway
runoff should be sheet flowed to the adjacent vegetation.
Additional Explorations
Based on our site observations during our recent site visit and a review of
published geotechnical literature, it is our opinion that no additional subsurface
explorations or slope stability model is necessary.
LIMITATIONS
We have prepared this report for use by the Suder's and members of their design
team, for use in the design of a portion of this project. The data and report should be
provided to prospective contractors for their bidding or estimating purposes only. Our
report, conclusions and interpretations should not be construed as a warranty of the
subsurface conditions.
Variations in subsurface conditions are possible between the available explorations
(well) and may also occur with time. A contingency for unanticipated conditions should be
included in the budget and schedule. Although proper planning, design, drainage and
construction techniques can reduce the risk of significant erosion and slope instability,
there is an inherent risk of instability associated with steep shoreline bluff sites.
The scope of our services does not include services related to environmental
remediation and construction safety precautions. Our recommendations are not intended
to direct the contractor's methods, techniques, sequences or procedures, except as specifi-
cally described in our report for consideration in design.
If there are any changes in the loads, grades, locations, configurations or type of
facilities to be constructed, the conclusions and recommendations presented in this report
• Suder Residential Remodel
December 31, 2007
Page 14
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.
Within the limitations of scope, schedule and budget, our services have been
executed in accordance with generally accepted practices in this area at the time this report
was prepared. No other conditions, express or implied, should be understood.
Respectfully submitted,
GeoResources, LLC
Brad P. Biggerstaff, LEG Glen Coad, PE
Principal Principal
W as� h; �
G GE L
F C�
ngineerin
1/ EXPIRES 10 / 31 r/
BPB:GC:bpb
Docl D:S uderN.NoShore Rd.RG
Enc: Figure 1-Vicinity Map
Figure 2-Site Sketch
Figure 3-Cross-Section
Figure 4:USDA SCS Map
Figure 5:Coastal Zone Atlas
Figure 6:Soil Classification System
Figure 7:Hand Auger Logs
Appendix"A"Slope Stability Analysis
3 Tra on �
.,I Rd 7; o � B
Erlanda
3D ,
i Point t
$. "A
L.. [181
Green j, rid..ah rk' ,rrd recreation Gent-
MAourdain ! _
�Alau Lain i Manchester
Penderijast -"-rort Orchard
RegionaI Park i --`_ 1 Yla}.e
K I T a. P 16 FL ; Or hard "T- Lland
r
0
`s
v Bre Tito
31
Sunnislope'
i� tong Lak
W A S H I N G T O N =—' �'
_ �r � —` Wash o n
o Mu'nici al
O
p ( 'Airport
.y r `" `" ° O•' f Vashon"
�.OIaha
KING
Vashon Islan$
11n
�.302
ahuya
3 I :Vaughn �' f�
ion — (�
N _
0trapeviewo -` -- . a ig Harbor'..
k r'� �� C 1. t Ruston
i (I Tacoma NarrovmAirport
Approximate Site Location
GeoResources, LLC
5007 Pacific Highway East, Suite 20 Site Location Map
Fife, Washington 98424 11031 North
Phone: 253-896-1011 Mason County, WA
Fax: 253-896-2633
File: SuderN.NorthShoreRD.SVM January 2008 Figure 1
CD
O
T
••� b `� r`,' L t
h, <-
___E p CA
Qn C
[A N v
IV
0 Aj
IrA
JA
F r1
1p
i 7-
� v
A
vkoCc a
C04
5ANo ( aeA G
mOr g'rAlliffIr®
S&.Opr
STAn e- ` �� ►o, ;r
s •\ RA-r
10
• ToP'.� .- j Foee;r ooFl-
P»sB To1�€WY $a�r�iJ�`f
-A\ �
s 3(.0. Gr r`o CIA-Z
s�
A
i "'
'1117 T HA-3 1
r sRlron uc e,2A�Eer 4 14A
SAIL Alp,
OA1 6At) e,S SANcco�ci: `
t 10 N R� 1�1 F.
- 40° C=15opsJ-
1
GeoResources, LLC 1 FIGUREB - dope Stability Cross
5007 Pacific Highway E., Suite 20 Project : sOv"ele eE-s'ocOeAr Section
Location "09mOr Soior r 2fQ
Fife, Washington 98424 MA5oN Covey W A
Ph: (253) 896-1011 Fax: (253) 896-2633 C'aent: rl-R OS -:vccr '
i4lo+ Job # SJE ev-N.O/JK
•- rr�� s
4 k-
i
4
'VR `#
e K I p y
At
4 cv f .
Cw
Approximate Site Location
GeoResources, LLC USDA SCS Soils Ma
5007 Pacific Highway East, Suite 20 p
Fife, Washington 98424 11031 NE North Shore Road
Phone: 253-896-1011 Mason County, WA
Fax: 253-896-2633
File: SuderN.NorthShoreRMSCS January 2008 Figure 4
r
•
e
u.
T '
ALI
r If
r �
A&oLE , ;�,, pov
f
Scale
U SOU
LL(LNi
-,uam+N PAION daft
9n w"04" aw.ww as gr.
• � r , .. .. rearre
}
Approximate Site Location
GeoResources, LLC
5007 Pacific Highway East, Suite 20 Coastal Zone Atlas
Fife,Washington 98424 11031 NE North Shore Road
Phone: 253-896-1011 Mason County, WA
Fax: 253-896-2633
File: SuderN.NorthShoreRD.CZA January 2008 Figure 5
SOIL CLASSIFICATION SYSTEM
MAJOR DIVISIONS GROUP GROUP NAME
SYMBOL
GRAVEL CLEAN GW WELL-GRADED GRAVEL, FINE TO COARSE
GRAVEL GRAVEL
COARSE GP POORLY-GRADED GRAVEL
GRAINED More than 50%
SOILS Of Coarse Fraction GRAVEL GM SILTY GRAVEL
Retained on WITH FINES
No.4 Sieve
GC CLAYEY GRAVEL
More than 50% SAND CLEAN SAND SW WELL-GRADED SAND, FINE TO COARSE SAND
Retained on
No.200 Sieve SIP POORLY-GRADED SAND
More than 50%
Of Coarse Fraction SAND SM SILTY SAND
Passes WITH FINES
No.4 Sieve SC CLAYEY SAND
SILT AND CLAY INORGANIC ML SILT
FINE
GRAINED CL CLAY
SOILS Liquid Limit
Less than 50 ORGANIC OL ORGANIC SILT,ORGANIC CLAY
SILT AND CLAY INORGANIC MH SILT OF HIGH PLASTICITY, ELASTIC SILT
More than 50%
Passes CH CLAY OF HIGH PLASTICITY, FAT CLAY
No.200 Sieve
Liquid Limit
50 or more ORGANIC OH ORGANIC CLAY,ORGANIC SILT
HIGHLY ORGANIC SOILS PT PEAT
NOTES: SOIL MOISTURE MODIFIERS:
1. Field classification is based on visual examination of soil Dry- Absence of moisture,dry to the touch
in general accordance with ASTM D2488-90.
Moist- Damp,but no visible water
2. Soil classification using laboratory tests is based on
ASTM D2487-90. Wet- Visible free water or saturated,usually soil is
obtained from below water table
3. Description of soil density or consistency are based on
interpretation of blow count data,visual appearance of
soils,and or test data.
GeoResources, LLC Soil Classification System
5007 Pacific Highway East, Suite 20 11031 NE North Shore Road
Fife, Washington 98424
Phone: 253-896-1011 Mason County, Washington
Fax: 253-896-2633
File: SuderN.NorthShoreRdI SC January, 2008 Figure 6
HAND AUGER LOGS
SUDER RESIDENTIAL PROPERTY
11301 North Shore Road
MASON COUNTY
HA-1 -Located upper slope above residence
Depth(ft.) Soil Type Description
0.0 - 0.5 Duff/Topsoil
0.5 - 1.0 SW Lt bru F-M SAND and GRAVEL w/silt,occ. cobbles
(med dense,moist),minor roots
1.0 - 2.0 SW Lt Brn F-M SAND and GRAVEL w/silt,oec.cobbles
(coed. dense to dense,moist)
2.0- 2.5 SM Lt brn SAND w/silt,cobbles
(dense to v.dense,moist)
Auger refusal at 2.5
Minor caving observed
No goundwater seepage observed
HA-2-Located mid slope above residence
Depth(ft.) Soil Type Deseription
0.0 - 0.1 Duff/Topsoil
1.0 - 2.0 SM Bm SAND w/silt,trace gravel
(loose to med dense,moist)
2.0 - 3.5 SP Bm silty SAND w/trace gravel,
(loose to med.dense,moist)
3.5 - 5.0 GM Bm silty GRAVEL w/sand,occ.Cobbles
(med dense,damp)
5.0 - 5.5 SM/GM Brn silty SAND and GRAVEL w/occ. Cobbles
(wet,dense)
Minor caving observed
Minor groundwater seepage at 4.5 feet
HA-3-Located at base of concrete retaining wall
Depth(ft.) Soil Tvpe Description
0.0 - 0.2 Duff/Topsoil
0.2 - 1.0 SP Lt.brn SAND w/silt,
(med dense,moist)
1.0 - 3.0 SW Brn/gray SAND w occ, gravel
(med dense,wet)
3.0 - 3.5 SW Gray SAND w/gravel,occ. Cobble,trace silt
(dense,wet)
Petroleum odor below 3-feet
Minor caving observed @1-foot
Minor goundwater seepage observed
FtbURE :;L
SUDGIe A),Ol,Z
HAND AUGER LOGS
SUDER RESIDENTIAL PROPERTY
11301 North Shore Road
MASON COUNTY
HA4-Located in crawl space below residence
Depth(ft.) Soil Type Description
0.0 - 1.0 SP/SW Bm Med SAND w/gravel,trace silt
(med dense,moist)
>1.0 SW/GW Brn/gray SAND and GRAVEL w/cobbles,silt
(cementd, dense,moist-damp)
Auger refusal
No caving observed
No goundwater seepage observed
HA-5—Above rockery in parking area
Depth(ft.) Soil Tyne Description
0.0 - 0.5 SW Brn SAND w/gravel(FILL)
(loose,moist)
>1.0 SW Lt brn F-M SAND w/gravel
(dense to v.dense,moist),minor roots
Auger refusal at 1-foot
Minor caving observed
No goundwater seepage observed
�'1tov�E
AI Zip
sod„ XIaN3ddd
Suder residence: North Shore Road, Mason County, pre-development (static) Safety Factors
84.38 - - -
1.50
1.51
67.50 1.54
1.59
1 .59
1.59
50.63 1.61
1 .62
1.63
33.75 1.66
16.88
00 16.88 33.75 50.63 67.50 84.38 101.25 118.13 135.00
Suder residence: North Shore Road, Mason County, pre-development (seismic) Safety Factors
84.38 — --
1.18
1.19
1.22
67.50 1.26
1.27
1 .27
50.63 1.28
1.28
1.29
33.75 1.30
16.88
I
0 16.88 33.75 50.63 67.50 84.38 101.25 118.13 135.00
Suder residence: North Shore Road, Mason County, post-development (static) Safety Factors
84.38 - --
1.50
1.51
67.50 1.54
1.59
1.59
1.59
50.63 1.61
1.62
1.63
33.75 1.66
16.88
0 16.88 33.75 50.63 67.50 84.38 101.25 118.13 135.00
I __
5
Suder residence: North Shore Road, Mason County, post-development (seismic) Safety Factors
84.38 - —
1.18
1.19
1.22
67.50
1.26
1.27
1.27
50.63 1.28
1.28
1.29
33.75 1.30
16.88
00 16.88 33.75 50.63 67.50 84.38 101.25 118.13 135.00
Profile.out
** PCSTABL6 �"
by
Purdue University
modified by
Peter J . Bosscher
University of wisconsin-Madison
--slope Stability Analysis--
simplified Janbu, simplified Bishop
or Spencers Method of slices
PROBLEM DESCRIPTION suder residence: North shore Road, Mason
County, post-development (static)
BOUNDARY COORDINATES
7 Top Boundaries
11 Total Boundaries
Boundary x-Left Y-Left x-Right Y-Right Soil Type
No. (ft) (ft) (ft) (ft) Below Bnd
1 0.00 10.00 35.00 10.00 1
2 35.00 10.00 35.00 14.00 1
3 35.00 14.00 42.00 14.00 1
4 42.00 14.00 89.50 56.00 1
5 89. 50 56.00 100.00 56.00 1
6 100.00 56.00 100.00 62.00 1
7 100.00 62.00 135.00 62.00 1
8 0.00 4.50 31.00 6.00 2
9 31.00 6.00 57.00 23.00 2
10 57.00 23.00 72.00 38.00 2
11 72.00 38.00 92.00 56.00 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.
1 125.0 128.0 250.0 36.0 0.00 0.0 1
Page 1
� ' 1
Profile.out
2 125.0 128.0 250.0 35.0 0.00 0.0 2
BOUNDARY LOAD(S)
5 Load(s) specified
Load x-Left x-Right Intensity Deflection
No. (ft) (ft) (lb/sqft) (deg)
1 6.00 7.00 2500.0 0.0
2 15.00 25.00 2500.0 0.0
3 25.00 33.00 2500.0 0.0
4 34.00 35.00 1500.0 0.0
5 99.00 100.00 2000.0 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 = 20.00 ft.
and x = 58.00 ft.
Each surface Terminates Between x = 80.00 ft.
and x = 110.00 ft.
unless Further Limitations were Imposed, The Minimum Elevation
At which A surface Extends Is Y = 0.00 ft.
20.00 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 5 coordinate Points
Point x-Surf Y-Surf
No. (ft) (ft)
Page 2
Profile.out
1 45.33 16.95
2 64.71 21.92
3 82.24 31. 54
4 96.85 45.19
5 107.60 62.00
circle center At X = 35.3 ; Y = 96.4 and Radius, 80.1
** 1.504 ***
Failure Surface Specified By 5 coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 45.33 16.95
2 63.90 24.38
3 80.99 34.77
4 96.13 47.84
5 107.88 62.00
circle center At X = 9.8 ; Y = 132. 5 and Radius, 120.9
*** 1. 509 ***
Failure surface specified By 5 coordinate Points
Point X-surf Y-Surf
No. (ft) (ft)
1 49. 56 20.68
2 68.67 26.56
3 85.67 37.09
4 99.45 51.59
5 105.18 62.00
circle center At X = 36.3 ; Y = 97.8 and Radius, 78.2
**� 1. 545 ***
Failure surface specified By 5 coordinate Points
Point X-surf Y-Surf
No. (ft) (ft)
1 45.33 16.95
2 64.40 22.99
3 80.06 35.43
4 90.24 52.65
5 90.81 56.00
Page 3
r y
Profile.out
circle center At X = 38. 5 ; Y = 71.6 and Radius, 55.1
1.585 ***
Failure surface Specified By 5 coordinate Points
Point X-surf Y-Surf
No. (ft) (ft)
1 49.56 20.68
2 68.82 26.07
3 85.28 37.42
4 97.19 53. 50
5 97.98 56.00
circle center At X = 43.0 ; Y = 81.2 and Radius, 60.8
1. 589
Failure surface specified By 5 coordinate Points
Point X-surf Y-surf
No. (ft) (ft)
1 45.33 16.95
2 65.13 19.79
3 82.71 29.33
4 95.89 44.37
5 102.63 62.00
circle center At X = 47.3 ; Y = 73.7 and Radius, 56.8
* 1. 591 ***
Failure Surface Specified By 5 coordinate Points
Point X-surf Y-Surf
No. (ft) (ft)
1 49. 56 20.68
2 68.84 26.00
3 84.86 37.96
4 95.43 54.95
5 95.62 56.00
circle center At X = 45.1 ; Y = 74.5 and Radius, 54.0
**� 1.605
Page 4
I
i
Profile.out
Failure Surface Specified By 5 Coordinate Points
Point x-Surf Y-Surf
No. (ft) (ft)
1 53.78 24.41
2 72.95 30.11
3 89.60 41.19
4 102.26 56.67
5 104.43 62.00
Circle Center At x = 44.4 ; Y = 91.0 and Radius, 67.3
*" 1.620 ***
Failure surface specified By 5 Coordinate Points
Point x-Surf Y-surf
No. (ft) (ft)
1 45.33 16.95
2 62.99 26.34
3 79. 56 37.54
4 94.87 50.41
5 106.04 62.00
Circle Center At x = -35.2 ; Y = 189.6 and Radius, 190. 5
** 1.625 **
Failure surface specified By 5 Coordinate Points
Point x-Surf Y-surf
No. ft ft
1 49. 56 20.68
2 67.39 29.73
3 84.25 40.49
4 99.97 52.85
5 109. 51 62.00
Circle Center At x = -33.4 ; Y = 206.3 and Radius, 203.3
1.659 ***
Y A X I S F T
Page 5
I ,
Profile.out
0.00 16.88 33.75 50.63 67. 50 84. 38
x0.00 +--' ---+---------+---------+---------+---------+
- 1/1
/2
16.88 +
.2/3
A 33.75 + *4*4
- . . 1
x 50.63 + 3
8
9
. . . . . . . 612
I 67.50 + . . . 53 0
8.
. . . . . . . .49.
6 1 2
5 84.38 + . . . . .3.0
8 4
. . . . . . .612.9 7
. . . . .355/5
101.25 + . . . . . . 0 *5
- . . . . . . . . . . .1
0
F 118.13 +
T 135.00 +
Page
Profile.out
PCSTABL6
by
Purdue University
modified by
Peter J . Bosscher
university of wisconsin-Madison
--slope Stability Analysis--
simplified Janbu, simplified Bishop
or spencers Method of slices
PROBLEM DESCRIPTION Suder residence: North Shore Road, Mason
County, post-development (seismic)
BOUNDARY COORDINATES
7 Top Boundaries
11 Total Boundaries
Boundary X-Left Y-Left X-Right Y-Right Soil Type
No. (ft) (ft) (ft) (ft) Below Bnd
1 0.00 10.00 35.00 10.00 1
2 35.00 10.00 35.00 14.00 1
3 35.00 14.00 42.00 14.00 1
4 42.00 14.00 89. 50 56.00 1
5 89. 50 56.00 100.00 56.00 1
6 100.00 56.00 100.00 62.00 1
7 100.00 62.00 135.00 62.00 1
8 0.00 4. 50 31.00 6.00 2
9 31.00 6.00 57.00 23.00 2
10 57.00 23.00 72.00 38.00 2
11 72.00 38.00 92.00 56.00 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.
1 125.0 128.0 250.0 36.0 0.00 0.0 1
Page 1
1' J
Profile.out
2 125.0 128.0 250.0 35.0 0.00 0.0 2
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
BOUNDARY LOAD(S)
5 Load(s) specified
Load x-Left x-Right Intensity Deflection
No. (ft) (ft) (lb/sgft) (deg)
1 6.00 7.00 2500.0 0.0
2 15.00 25.00 2500.0 0.0
3 25.00 33.00 2500.0 0.0
4 34.00 35.00 1500.0 0.0
5 99.00 100.00 2000.0 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 = 20.00 ft.
and x = 58.00 ft.
Each Surface Terminates Between x = 80.00 ft.
and x = 110.00 ft.
unless Further Limitations were
Imposed, The Minimum Elevation
At which A Surface Extends Is Y = 0.00 ft.
20.00 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.
Page 2
10
1
Profile.out
Safety Factors Are calculated By The Modified Bishop Method
Failure surface Specified By 5 coordinate Points
Point x-Surf Y-Surf
No. (ft) (ft)
1 45.33 16.95
2 64.71 21.92
3 82.24 31. 54
4 96.85 45.19
5 107.60 62.00
circle center At x = 35.3 ; Y = 96.4 and Radius, 80.1
1.185 ***
Failure surface specified By 5 coordinate Points
Point x-surf Y-surf
No. (ft) (ft)
1 45.33 16.95
2 63.90 24.38
3 80.99 34.77
4 96.13 47.84
5 107.88 62.00
circle center At x = 9.8 ; Y = 132.5 and Radius, 120.9
** 1.186 ***
Failure Surface specified By 5 coordinate Points
Point X-surf Y-Surf
No. (ft) (ft)
1 49.56 20.68
2 68.67 26. 56
3 85.67 37.09
4 99.45 51. 59
5 105.18 62.00
circle center At x = 36.3 ; Y = 97.8 and Radius, 78.2
*** 1.220 ***
Failure surface specified By 5 coordinate Points
Page 3
i
Profile.out
Point X-Surf Y-Surf
No. (ft) (ft)
1 49.56 20.68
2 68.82 26.07
3 85.28 37.42
4 97.19 53. 50
5 97.98 56.00
Circle Center At X = 43.0 ; Y = 81.2 and Radius, 60.8
1.257 *
Failure surface Specified By 5 Coordinate Points
Point x-Surf Y-Surf
No. (ft) (ft)
1 45.33 16.95
2 65.13 19.79
3 82.71 29.33
4 95.89 44.37
5 102.63 62.00
Circle Center At X = 47.3 ; Y = 73.7 and Radius, 56.8
*�
1.267
i
Failure surface specified By 5 Coordinate Points
Point x-Surf Y-Surf
No. (ft) (ft)
1 45.33 16.95
2 64.40 22.99
3 80.06 35.43
4 90.24 52.65
5 90.81 56.00
Circle Center At X = 38.5 ; Y = 71.6 and Radius, 55.1
** 1.269
I
�I
Failure surface Specified By 5 Coordinate Points
I
Point X-surf Y-surf
No. (ft) (ft)
1 49. 56 20.68
Page 4
i
I
1
Profile.out
2 68.84 26.00
3 84.86 37.96
4 95.43 54.95
5 95.62 56.00
Circle Center At x = 45.1 ; Y = 74.5 and Radius, 54.0
1.278 ***
Failure surface Specified By 5 Coordinate Points
Point x-surf Y-Surf
No. (ft) (ft)
1 53.78 24.41
2 72.95 30.11
3 89.60 41.19
4 102.26 56.67
5 104.43 62.00
Circle Center At x = 44.4 ; Y = 91.0 and Radius, 67.3
II� 1.280 ***
I
Failure surface specified By 5 Coordinate Points
Point x-Surf Y-Surf
No. ft ft
C ) C )
1 45.33 16.95
2 62.99 26.34
3 79. 56 37. 54
4 94.87 50.41
II 5 106.04 62.00
Circle Center At x = -35.2 ; Y = 189.6 and Radius, 190. 5
*** 1.287 ***
Failure
Surface specified By 5 Coordinate Points
Point x-Surf Y-Surf
No. (ft) (ft)
I
1 49. 56 20.68
2 67.39 29.73
3 84.25 40.49
4 99.97 52.85
5 109. 51 62.00
Circle Center At x = -33.4 ; Y = 206.3 and Radius, 203.3
Page 5
�I
I
I
� Q
Profile.out
** 1.300 **
Y A x I 5 F T
0.00 16.88 33.75 50.63 67.50 84.38
x0.00 +--*-- ---+---------+---------+---------+---------+
- 1/1
/2
16.88 +
- .2/3
A 33.75 + *4*4
1
x 50.63 + 3
- . . 8
_ g
- . . . . . . . 512
I 67. 50 + . . . 43 0
. . 8.
. . . . . . . 69.
. . 512
5 84.38 + . . . . .3.0
8 . 6 *
. . . 512.9 7
. . . . .344/5
101.25 + . . . . . . 0 *5/
. . . . . 3
. . . . . . . . . . 1
0
F 118.13 +
T 135.00 +
j Page 6
I