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Report MS1 0 - E� I �h S July 27, 2007 Christopher Varney RECEIVED 10958 Southwest Durham Rd, Apt 28 Tigard, Oregon 97224 j JUN 16 7 Subject: Geotechnical Engineering Report CITY OFTIGARD Proposed Single Family Residence BUILDING DIVISION 13765 Southwest Lauren Lane Tigard, Oregon CGI Report No. 07-135-1 Dear Mr. Varney: As you requested, Chinook GeoServices, Inc. (CGI) is pleased to submit our Geotechnical Engineering Report for the proposed single family residence on the subject property. Our services were completed in general accordance with our CGI Proposal No. 07-P199 dated June 29, 2007. Our services were authorized by you by signing and returning the Proposal Acceptance Form on June 29, 2007. You provided us with a basement floor plan with local topography dated June 8, 2007. Scope of Work We explored the subsurface soil conditions at the site in order to evaluate soil conditions and to provide design and construction recommendations for the proposed single family residence. We have also provided recommendations for site preparation, grading, fill compaction, drainage, and other geotechnical design and construction considerations for site development. We conducted the following scope of services: 1. Subsurface exploration including four drive probe explorations and three hand auger borings. 2. Geologic background research. 3. Preparation of geologic hazard conclusions and geotechnical engineering recommendations for: • Grading Recommendations • • Trench Excavation and Dewatering • Shallow Foundation and Retaining Wall Recommendations • Wet Weather Construction • Floor Slab Subgrade Support • Seismic Site Class in Accordance with the 2007 Oregon Structural Specialty Code (OSCC) • Other pertinent geotechnical design and construction recommendations 1508 Broadway Street• Vancouver, Washington 98663 • Phone 360-695-8500 • Fax 360-695-8510 • zc)- 13-7 c_A f is F-1 CAT7a J OF SIZE O _ (4ce...11;?7aws - 1 OA-LA CUT it CAT"S C l -S ®M S - c ow Eo Tom- _ I DJSULArto-eL) j ic)c--A4cTF-t rReieS FO42-5--(EN2 "To C'i Chinook GeoServices, Inc. Proposed Single Family Residence—Southwest Lauren Lane CGI Report No. 07-135-1 July 27, 2007 Page 2 of 9 Site and Project Description The site location is shown on Figure 1, Site Location Plan, attached at the back of this report. The project site is located at 13765 Southwest Lauren Lane in the City of Tigard, Washington County, Oregon. The property is on the north side of Southwest Lauren Lane approximately 70 feet west of Southwest Essex Drive at the western termination of Southwest Lauren Lane. The subject property is comprised of Tax Lot 2S104CA01800. The property borders single family residences to the south and east, a commercial property to the north and undeveloped land to the west. The site is vegetated with a mix of large old trees and young alder trees. Elevations on the site range from about 460 feet to 380 feet above mean sea level. The proposed building envelope falls approximately between 455 feet and 425 feet above mean sea level. The site slopes down significantly to the north from Southwest Lauren Lane at a grade of roughly 75 percent. There is an existing retaining wall supporting a concrete driveway and a retaining wall along the eastern property margin supporting the neighbor's walkway. We observed that soil, landscaping debris and garbage have been dumped onto the site from Southwest Lauren Lane. You provided us with a basement floor plan with local topography dated June 8, 2007. The proposed single family residence will consist of a daylight basement below street level with the garage and first floor at street level. The foundation of the house extends to the north roughly 52 feet from the garage and is roughly 27 feet wide. It is our understanding that shallow spread footing foundations are planned and that the up slope foundation footings will be excavated to depths level with the lowest foundation elevation. According to the local topography the deepest cut would be around 30 feet. Soils and Geology Summary Soils mapped in the project area in the United States Department of Agriculture (USDA) Soil Survey of Washington County, consist of Cornelius and Kinton silt loarns, 20 percent to 30 percent slopes. The Cornelius and Kinton soils consist of deep, moderately well-drained soils formed in loess-like material over old alluvium derived from mixed sources. The soils are found on low hills. The USDA describes the profile of this soil as silt loam to depths of 61 inches, with silty clay loam between 17 inches and 38 inches in the Cornelius soil. A dense, brittle fragipan layer exists between roughly 30 inches and 40 inches that has reduced permeability. The near surface geologic units at the project site are mapped as Pleistocene fine-grained facies of catastrophic flood deposits (Off) as shown on the Preliminary Digital Compilation Map of the Portland Urban Area, Oregon Department of Geology and Mineral Industries (DOGAMI), Open-File Report 0-04-02, 2004 by Ian P. Madin. This unit was deposited by a series of glacial outburst floods from glacial Lake Missoula approximately 12,000 years to 15,000 years ago. The series of events flooded areas adjacent to the Columbia River. The flooding also extended well up the Willamette Valley. Chinook GeoServices,inc. Proposed Single Family Residence—Southwest Lauren Lane CGI Report No. 07-135-1 July 27, 2007 Page 3 of 9 Subsurface Explorations Subsurface soil conditions were explored by Chuck Bolduc and Sunny Simpkins, Geologic Staff of CGI, who visited the site on July 17, 2007. We advanced four drive probe explorations and three hand auger borings adjacent to the proposed exterior foundation walls. Explorations were conducted at the northeast corner, northwest corner and southwest corner of the proposed foundation perimeter. Figure 2, Site Plan with Exploration Locations, shows the locations of the drive probes and hand auger borings. The drive probe exploration method is a "relative density" exploration technique that is used to estimate strength of the subsurface soil and decomposed bedrock units. The resistance to penetration is measured in blows-per-% foot of an 11-pound hammer which free falls roughly 3% feet, driving a 1-inch diameter pipe coupler into the soil by its threaded connection with %- inch diameter pipe. Pipe sections are added by threaded couplers of larger diameter to reduce accumulated friction of the added pipe length. This geotechnical exploration technique was developed by Douglas Williamson, C.E.G. of the United State Forest Service in Oregon's Willamette National Forest to supplement geotechnical subsurface data from drilled borings in areas restricted to drill rig or excavator access. This exploration technique does not produce soil or weathered rock samples for observation and testing, but does provide a generally continuous subsurface profile of penetration resistance which correlates well with changes in relative density of fill or native soil, changes in near-surface soil stratigraphy, contacts with weak slide planes, shallow bedrock, gravel, or boulder occurrences, and contacts with perched or static groundwater levels. The drive probe results show medium stiff layers in the upper 4.5 feet on drive probes DP-1 and DP-2 with soils becoming relatively stiff to depths of 6.5 feet to 8 feet. Drive probes DP-3 and DP-4 encountered relatively stiff soils to depths of 2 feet before meeting refusal on rock or debris. Soil recovered from hand auger borings HA-1 and HA-2 generally consisted of dry to moist brown silt with clay and roots to depths of 6 feet to 7 feet. Below this we encountered mottled silty clay to depths of 6.5 feet to 8.5 feet. Hand auger boring HA-3 encountered dry to moist brown clayey silt with roots and rock fragments before meeting refusal on a rock at 2 feet. Descriptive logs of drive probe and hand auger explorations are included at the end of this report. Based on our hand auger borings and site observations it is our interpretation that the soils encountered in our explorations are likely manmade fill, probably dumped onto the site from Southwest Lauren Lane and from construction of the residence to the east. Partially buried silt fencing was observed throughout the southwest area of the site. Older tree trunks had been buried with fill. The depth and extent of the fill in the foundation area is not known, but it may be widespread. Excavations will be needed to determine the depth to native soil. Chinook GeoServices,Inc. Proposed Single Family Residence—Southwest Lauren Lane CGI Report No. 07-135-1 July 27, 2007 Page 4 of 9 Groundwater We did not observe perched or static groundwater or seepage in our drive probe explorations or hand auger borings. Perched groundwater could occur in the on-site materials following extensive periods of wet weather. We recommend that adequate drainage be installed for any - below grade retaining walls constructed for the project. Lot Specific Slope Stability Reconnaissance According to the local site topography, slopes grades on the site are between 8D percent and QQ percent in the upper areas of the slope. Slope grades near the lower areas of the proposed building are between 45_ rat and 711pprrenL The steep slope north of Southwest Lauren Lane shows some signs°f slnpa instability. Large diameter trees have grown fairly straight, but younger alder trees have bent trunks. Buried utility wires and pipes have become exposed at the crest of the slope where there is a small scarp. Some foundation cracking was observed in the residence to the east and a failing retaining—wall was observed on the south side of Southwest Lauren Lane. The over-steepened crest of the slope is probably caused by dumping of debris from Southwest Lauren Lane. The straight older trees and bent younger trees suggest that shallow soil creep is occurring in the more recently dumped fill. A detailed slope stability analysis is beyond the scope of this report, but can be provided if requested. Conclusions and Geotechnical Recommendations Based on our site reconnaissance, subsurface soil exploration and geologic background research, it is our professional opinion that construction of a single family residential structure on the subject site is feasible. However, a conventional shallow spread foundation system as proposed will be dependent on the soils encountered in the excavations. It is our interpretation that a significant amount of undocumented fill has been dumped onto the subject site. Footings should be founded below this fill material to avoid slope stability or settlement concerns associated with the undocumented fill. Our subsurface explorations did not convincingly reach firm native soils appropriate for foundation support. Our foundation design recommendations will be made in a subsequent report once foundation excavations have revealed the subsurface conditions. Excavation may continue based on the following recommendations of this report. Site Preparation — All foundation areas should be excavated to a depth that is sufficient to remove uncontrolled fill, topsoil, roots, and any other deleterious materials encountered, but no deeper than is appropriate for shallow spread footing foundations. CGI's Geotechnical Engineer should be contacted to review the excavated subgrade and determine if a shallow spread footing foundation is feasible and to verify our recommendations for retaining wall pressures. Stripped soils will not be suitable for re-use as structural fill. Stripped fill and topsoil should be exported from the site or used in landscaped areas. During and after construction, existing plant cover should be maintained on the adjacent slopes to help control erosion. Chinook GeoServices,Inc. Proposed Single Family Residence—Southwest Lauren Lane CGI Report No. 07-135-1 July 27, 2007 Page 5 of 9 Structural Fill Recommendations - All required structural fill materials should be moisture conditioned within 2 percent of optimum moisture content and compacted by mechanical means to a minimum of 95 percent of the materials maximum dry density as determined in accordance with ASTM D1557 (Modified Proctor). If water must be added, it should be uniformly applied and thoroughly mixed into the soil by disking or scarifying. Fill materials should be placed in layers that, when compacted, do not exceed about 8 inches. Compacted engineered fill should be observed or tested by a representative of the geotechnical engineer. Fills should be benched horizontally into firm native soils. If structural fills greater than 5 feet in height other than required retaining wall back fill are proposed, we should be contacted to review the location and height of proposed fills and provide additional recommendations as warranted. We recommend that the Geotechnical Engineer be contacted to review final grading and foundation designs to check that our recommendations have been properly interpreted. We also recommend that general site grading and footing subgrades should be observed by a representative of the Geotechnical Engineer to verify that subgrade soils and footing elevations are similar to those anticipated based on our subsurface exploration of the building site. These observations should be conducted prior to placing forms or concrete for footings. Graded Cut and Fill Slopes - We expect that the southwestern area of the foundation will require deep cuts into the existing slope. To avoid loss in stability these cuts should not be left exposed for an extended period. Temporary earth slopes may be cut to near-vertical slopes to a height of 4 feet, above which flatter slopes will be required in accordance with OSHA. Permanent earth slopes should be graded to no steeper than 2 horizontal to 1 vertical (2H:1V) and protected from erosion. Any graded slopes greater than 5 feet in height above the original native ground surface should be reviewed in advance by the geotechnical engineer. Foundation Bearing CapacitOk.edtr. the building footprint has been excavated to proposed foundation subgrade elevation, CGI's Geotechnical Engineer should determine if the structure may be supported on conventional shallow spread footings or on deeper pier foundations. A structure supported on stiff undisturbed native soil may be designed for a maximum contact pressures of 2,500 pounds per square foot (psf), with an allowable 1/3 increase for short term wind or seismic loads. The soil resistance available to withstand lateral foundation loads is a function of the frictional resistance which can develop on the base and the passive resistance which can develop on the face of below-grade elements of the structure as these elements tend to move into the soil. For spread footings founded on firm native soil, the allowable frictional resistance may be computed using a coefficient of friction of 0.30 applied to vertical dead-load forces. The allowable passive resistance on the face of footings or other embedded foundation elements may be computed using an equivalent fluid pressure of 230 pounds per cubic foot (pcf) (triangular distribution) for the anticipated foundation soils. The above coefficient of friction and passive equivalent fluid density values include a factor of safety of about 1.5. Chinook GeoServices,Inc. Proposed Single Family Residence—Southwest Lauren Lane CGI Report No. 07-135-1 July 27, 2007 Page 6 of 9 Slab-on-Grade Floors - Floor slabs-on-grade should be supported on compacted engineered fill placed over firm native soils. CGI's Geotechnical Engineer or an authorized representative should be requested to observe excavated floor slab subgrade, witness placement and compaction of structural fills, and observe proof-rolling with a loaded dump truck to confirm its firmness. In order to provide uniform subgrade reaction beneath any proposed floor slab-on- grade, we recommend that floor slabs be underlain by a minimum of 6 inches of compacted crushed rock base course. Base course material should consist of a well-graded 1% inch or 3/4 inch minus or similar gradation crushed rock having less than 5 percent material passing the No. 200 sieve. Base course material should provide a capillary break to limit migration of moisture through the slab. If additional protection against moisture vapor is desired, a vapor retarding membrane may also be incorporated into the floor design. Factors such as cost, special considerations for construction, and the floor coverings suggest that decisions on the use of vapor retarding membranes be made by the architect and owner. If a basement floor slab is contemplated, we recommend that perforated subsurface drainage pipes be installed under the floor slab to collect and convey any subsurface water that might develop at the floor slab subgrade or base rock elevation. These drains should be sloped to drain by gravity to discharge with subsurface foundation and retaining wall drains. Seismic Design - In accordance with Table 1613.5.2 of the 2007 State of Oregon Structural Specialty Code (OSSC), we recommend a Site Class E for this site when considering the average of the upper 100 feet. According to the 2002 United States Geological Survey (USGS) Earthquake Hazards website http://egint.cr.usgs.qov/eq-men/html/lookup-2002-interp-06.html, the Peak Ground Acceleration (PGA) predicted for the site is 0.3`x, and the maximum considered earthquake (MCE) ground motions for the site are S =0.916g and SSA—O. g (for Site Class B and 5 percent critical damping). The USGS website values are a more accurate interpolation of the values presented in Figure 1613.5 (1) of the 2007 OSSC. In accordance with Tables 1613.5.3 (1) and 1613.5.3 (2), Site Coefficients Fa and Fv are 0.998 and 2.659, respectively for a Site Class E. Therefore the adjusted MCE ground motions are SMS=0.916g and SM1=0.891g (for Site Class E). The return interval for these ground motions is 2 percent probability of exceedance in 50 years. A complete site-specific seismic hazard study was beyond the present scope of services for this project. It is our opinion that the project may be designed in accordance with IBC design criteria. Retaining Wall Recommendations — Active lateral earth pressures on walls which are not restrained at the top, such as free standing retaining walls, etc., may be calculated on the basis of an equivalent fluid pressure of 30 pounds per cubic foot (pcf) for level backfill and 60 pcf for sloping backfill less than two horizontal to one vertical (2H:1V). Basement or other retaining walls that are restrained from yielding at the top may be calculated on the basis of an equivalent fluid pressure of 55 pcf for level backfill and 90 pcf for sloping backfill less than 2H:1V. Lateral loads may be resisted by passive pressures acting against footings and by frictional resistance between foundation elements and supporting soils. The earth pressures are also based on the Chinook GeoServices,Inc. Proposed Single Family Residence—Southwest Lauren Lane CGl Report No. 07-135-1 July 27, 2007 Page 7 of 9 assumption that retaining walls will be properly drained to prevent hydrostatic buildup behind walls. Design lateral earth pressures during seismic loading were determined using the pseudostatic Mononobe-Okabe method. For the design event, we took 2/3 of the MCE value, per the 2004 SOSSC. We then assumed a horizontal acceleration of 0.75 times the factored peak ground acceleration for structural walls to account for the inherent conservatism of the pseudostatic design method. This results in the horizontal ground acceleration of 0.19g for use in design of structural walls. Recommended design earthquake loading APAE, for structural walls is therefore 7.2H2, where H is the total height of the wall. This loading is for a flat backslope. CGI can provide soil pressures for other loading conditions upon request. Retaining walls should be designed to withstand surcharge loads from adjacent foundations, vehicle loads, fills or slopes. We should be contacted to review retaining wall designs and observe their, construction, drainage, and backfill. All backfill for retaining walls, foundation walls, etc., should consist of approved free draining granular material (sand and/or sandy gravel). We anticipate that on site material will not be suitable for this purpose and that it will be necessary to import material to the project for structural backfill. Fine-grained soil can be used for the last 18 inches to 24 inches of the fill to act as a seal to the granular fill. A geotextile filter layer should be used be between the granular wall backfill and any fine-grained soil above it. This fine grained fill should be graded to drain away from retaining walls and backfilled areas. Subsurface Drainage — An adequate subsurface drain system should be installed behind below grade building and retaining walls. We recommend placing a 4-inch diameter, perforated drain pipe at the base elevation of the wall foundation. This drain should be covered by washed drain rock enclosed in non-woven filter fabric. The subsurface foundation drains should be routed to drain by gravity to discharge at a lower elevation than the basements. Surface Drainage - All roof, yard, and other upland surface water should be directed independently to approved discharge points. Surface runoff should not be added to the home's subsurface drain system. The site should be graded to provide positive surface drainage away from embedded walls, retaining wall backfill, and foundation areas. Surface run-off drains and the subsurface drains should be routed to discharge at a lower elevation below of the proposed homes. Subsurface Excavation Stability- Stability of temporary excavations is the responsibility of the contractor, who must maintain safe excavation slopes and/or shoring. Excavations must comply with the current requirements of OSHA and the State of Oregon. We are providing the information below solely as a service to our client. Under no circumstances should the information provided be interpreted to mean that CGI is assuming responsibility for construction site safety or the contractor's activities. Chinook GeoServices, Inc. Proposed Single Family Residence—Southwest Lauren Lane CG/Report No. 07-135-1 July 27, 2007 Page 8 of 9 The contractor should be aware that slope height, slope inclination, or excavation depths (including utility trench excavations) should in no case exceed those specified in local, state, and/or federal safety regulations (e.g., OSHA Health and Safety Standards for Excavations, 29 CFR Part 1926, or successor regulations). Such regulations are strictly enforced and, if they are not followed, the Owner, Contractor, and/or earthwork and utility subcontractors could be liable for substantial penalties. Based upon our explorations, we anticipate that most of the excavations for cuts and utilities can be accomplished using conventional equipment but the subcontractor should be prepared for the possibility of miscellaneous buried debris. Any excavations that personnel must enter should be adequately sloped or should be shored if they are deeper than 4 feet, or if loose soils or groundwater seepage are encountered. In our opinion the near surface soils encountered in the test pits excavated would generally be considered a Type C soil when applying the OSHA regulations. For Type C soils the maximum recommended slope inclination is 1.5H:1 V. Flatter slopes and/or trench shields may be required if loose, cohesionless soils and/or water are encountered along the slope face. The recommended maximum inclination for temporary slopes assumes that the ground surface behind the cut slope is level, that surface loads from equipment and materials are kept a sufficient distance away from the top of the slope (typically at least half the slope height), and that utility trench excavations are completed and backfilled prior to the construction of structures adjacent to the excavations. If these assumptions are not valid, we should be contacted for additional recommendations. Limitations The engineering geologic and geotechnical engineering services performed for this project have been conducted with that level of care, skill, and judgment ordinarily exercised by members of the professional community currently practicing in this area under similar budget and time restraints. No warranty, expressed or implied, is made. Chinook GeoServices, Inc. Proposed Single Family Residence—Southwest Lauren Lane CGI Report No. 07-135-1 July 27, 2007 Page 9 of 9 We will be available for further consultation and geotechnical observation of soil exposures and grading during the remaining design and construction phases of this project. If you have any questions regarding our recommendations, please call us at (360) 695-8500. Sincerely, Chinook GeoServices, Inc. PROFt. 4400L*0INth,s''p� 16,$00 I ,$REG Q %t 1■5st,r-NIA,11+-- CV1‘174' EXPIRES 12/31/0 Marcella M. Boyer, P.E., G.E. Charles Bolduc Principal Geotechnical Engineer Geologic Associate Attachments: Figure 1: Site Location Plan Figure 2: Site Plan with Exploration Locations Exploration Logs FIGURE 1: SITE LOCATION PLAN 122°50.000' W 122°49.000' W WGS84 122°48.000' W : �F) A �`` �.a� '\%- s • r S Q SWA ' - ___ 7 NO WY OWL LN -- E� '',/7-1 c _ ��i 1' J � iJ• f � ®®,, / Q p 210 r l —QOr`�r ° S o _ N /f ? 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Tigard, Oregon 9 Date: July 27, 2007 FIGURE 2: SITE PLAN WITH EXPLORATION LOCATIONS kA-a � •' �-`- /d ;•_ j •, ••-, , :' �\'.• _.. V I L J' : k ., � •. . e ' ...... ,, . .......... ..„„. .... ..,,, ' t a: 'ri*. IN.----,,,-", 1 ; : "t.R '� i. '+ 1.`' , �, O� - ti am ,? om � , S . -s'ti ~ t N. ate' ,,''n 4 `It -\ \ 4-1 .� ....,, ..,„,"4 1110. I, . :::::::::::-.,.-----„Nter\-.,a!k. '\.,.\\* \‘'�. + °: ,.� ,. L \\ : \\.-.... .,\\ N, \N.�. � y a`� ��yt `' � �1, ,,,tea ' .. � '+,d. /� _ T - . ■ 1.�" ` r tat .!�'.�, �j• -- - / �_' — iv .!! s{1 �Ffl;`►"��1►'i�rte►i17t'1i.li ZS) ' ^�VAti� S'� •al l•' s..a -1 �• 1 1 Y� "• �♦ l \, \\", 1V8401:, ids f ' —., --47A \ \ 1 iotA ....\- \ti- - .„..,5._ /W----,,,,,,,‘, -0... .. \ \ \ 4\0 \ \\ , \ \ \ gittor4-1 ''', N \\ \ I% vii, \ ' ''' \ \ \ \\\:. 111046: '',, ''''s , -,., ---\,,, I ' - 'it Vii"-------_ ----.,..,,, \\\ ,i . \ 4, \-, \ \ ' .4%,N ..000% . diNo. No .\, - ---,, .141,4i ii. "...,,,., \\ \ lk , s \ .„,_ . .... _...... ,,, , , .2\ 10,, , \\\. \ \ \\:\ ..\ \ N, N_.,...00lik \\ ‘. \ \h. . ,Thh- .: *111111111,a0+-44 \\N.,\ \ \.**\ \ 'V \ \.\#,..;,0•00"- 'N , \ 'Ilo. 1..-7,:i 4 i lik7 11 1 I litlia‘ :\i81 1:egg 0•or of 0 0.1.•4 4 A • - - \ fit' . ti \',, Legend • Approximate Location of Hand Auger Borings. Approximate Location of Drive Probe Explorations. Source:Provided by Client Scale: NTS Report No. Proposed Single Family Residence 07-135-1 13765 Southwest Lauren Lane tw "'C�i000k GeoServicos inc. Tigard, Oregon Date: July 27, 2007 achinook • Inc. Geotechnical Exploration-Drive Probe Method The Drive probe method is a "relative density" exploration technique that is used to estimate strength of the subsurface soil and decomposed bedrock units. The resistance to penetration is measured in blows per 1/2 foot of an 11-pound hammer which free falls roughly 3.5 feet driving the 1/2 inch diameter pipe into the ground. For a more detailed description of this geotechnical exploration method, please refer to the Slope Stability Reference Guide for National Forests in the United States, Volume I, United States Department of Agriculture, EM-7170-13, August 1994, p. 317-321. The following tables depict drive probe penetration resistance per depth for the probe exploration locations shown on the site plan included with this report. Our interpretations of subsurface conditions are discussed in the accompanying report text. 1508 Broadway Street•Vancouver, WA 98663.phone: 360-695-8500•fax: 360-695-8510 www.chinookgeoservices.com 1 rachiflook geosefyic es Inc. DEPTH DP-1 DP-2 DP-3 DP-4 (FEET) (Blows (Blows (Blows (Blows per 6") per 6") per 6") per 6") 0.0-0.5 15 5 9 17 0.5-1.0 10 4 18 23 1.0-1.5 14 8 24 24 1.5-2.0 9eotextile 6 22 20 2.0-2.5 18 10 refusal refusal 2.5-3.0 12 11 3.0-3.5 12 12 3.5-4.0 13 10 4.0-4.5 14 15 4.5-5.0 18 20 5.0-5.5 20 24 5.5-6.0 24 23 6.0-6.5 27 29 6.5-7.0 26 7.0-7.5 18 7.5-8.0 24 1508 Broadway Street•Vancouver, WA 98663.phone: 360-695-8500.fax: 360-695-8510 www.chinookgeoservices.com 1 HA-1 0 - 1.5' Dry to moist silt-topsoil with rocks and roots. 1.5 - 3.5' Dry, brown silt with clay. 3.5 - 6.0' Dry, brown with tan mottled silt with clay. • Roots present. 6.0 - 7.0' Dry to moist, brown with tan mottled silty clay. • Roots present. 7.0 - 8.5' Moist to wet, brown with tan mottled silty clay with more clay. • Sample 1 taken at 8 feet. HA-2 0 - 2.5' Dry, soft, brown topsoil with roots. Dry to moist, medium stiff, brown with faint mottling, silt with 2.5 - 6.0' clay. • Roots present. 6.0 6.5' Brown with tan mottling. More clay. • Sample 1 taken at 6.5 feet. HA-3 - 2 �, Medium dense, dry to moist, brown clayey silt with rock 0 fragments, roots and brush debris. _ 2.0' Refusal on rock at 2 feet. Report No. 07-135 . . - �f]'/]fj��/ IisuSBrvicss 'nc. Hand Au ger Boring Log fl !((J J, Proposed Varney Residence