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hoovergeotech.pdfSTREET FILE Geotechnical Engineering Report Meadowdale Estates Edmonds, Washington For Hoover Premier Homes zp' DEV4CIn' 0� � MO ICES Cl NDg _r n January 6, 2005 Ms. Cathy Patterson Hoover Premier Homes 16300 Mill Creek Boulevard, #108 Mill Creels, WA 98012 Geotechnical Engineering Report Meadowdale Estates Edmonds_ WashinL CG File No. 1791 Dear Ms. Patterson: 77625 -130th Ave. NE, 0102, Woodinville, WA 98072 Phone: 425-844-1977 Fax: 425-8444987 INTRODUCTION This report presents the results of our geotechnical engineering investigation for your Meadowdale Estates residential development in the Meadowdale area of Edmonds, Washington. The site is located at 6880 -172"d Street SW, as shown on the Vicinity Map in Figure 1 _ Site development, including grading, road construction, and utility placement, has been substantially completed_ We understand that you have purchased all of the building lots, with the exception of Lot 2, for the purposes of constructing single-family residences. The City of Edmonds has required a geotechnical report for the lots with slopes greater than 15 percent, and you have requested that we evaluate the subsurface conditions of your lots and provide foundation recommendations for the proposed residences. For our use in preparing this report, we have been provided with a copy of a site plan by CHS Engineering, dated September 2003, that shows lot, road, and utility layout. We have also been provided with a Slope Stability Evaluation, prepared by GeoEngineers and dated June 18, 2002, that addresses the detention facility. Additionally, we have been provided with field reports prepared by Sky Valley Testing that document compaction testing performed during the main earthwork phase of the project. PROJECT DESCRIPTION The L-shaped project site has maximum dimensions of approximately 640 feet north to south and 440 feet east to west. The development consists of a total of 12 lots. We understand that you intend to construct Geotechnical Engineering Report Meadowdale Estates Edmonds, Washington _. January 6, 2005 CG File No. 1791 Page 2 single-family residences on all of the lots with the exception of Lot 2, which you do not .own. The provided grading plan indicates cuts totaling 6,000 cubic yards (CY) and fills totaling 1.2,000 CY. The grading plan also indicates that fills may be at least 12 feet deep in some areas. At this point in time, site grading has been completed and utilities have been installed. A completed storm water detention vault is located close to the western site boundary. SCOPE The purpose of this study is to explore and characterize the subsurface conditions and present recommendations for site development. Specifically, our scope of services as outlined in our Services Agreement, dated December 23, 2004, includes the following: 1. Review available geologic maps of the area and available project documentation. 2. Explore the subsurface conditions at the site with backhoe -excavated test pits. 3. Provide recommendations for building' foundations, including lateral pressures for retaining walls. 4. Provide recommendations for site preparation and grading. 5. Provide general recommendations for site drainage. 6. Prepare a written report to document our conclusions and recommendations. SITE CONDITIONS Surface Conditions At the time of our exploration, the access road (69`h Place W) was paved. Site grading was also complete and grass was growing. on all, of the lots. The storm water detention vault and utilities had all been completed, but no residences had been constructed yet. A layout of the site is showri on the Site Plan in Figure 2. Generally, the ground surface slopes downward towards the west at approximately 3 Horizontal to 1 Vertical (3H: IV).. An existing residence borders the southwestern corner of the site and 172'd Street SW borders the site to the south The rest of the site is surrounded by a wooded area with brush and evergreen trees up to approximately 2 feet in diameter. Cornerstone Geotechnical, Inc. Geotechnical Engineering Report �Meadowdale Estates Edmonds; Washington January 6, 2005 CG File No. 1791 Page 3 Geology Most of the Puget Sound Region was affected by past intrusion of continental glaciation. The last period of glaciation, the Vashon Stade of the Fraser Glaciation, ended approximately 11,000 years ago. Many of the geomorphic features seen today are a result of scouring and overriding by glacial ice. During the Vashon Stade, much of the Puget Sound region was overridden by over 3,000 feet of ice. Soil layers overridden by the ice sheet were compacted to a much greater extent than those that were not. Part of -a typical glacial sequence includes recessional outwasb sand underlain by glacial till. The site is mapped as being underlain by glacial till (Preliminary Surficial Geologic Map of the Edmonds East and Edmonds West Quadrangles, Snohomish and King Counties, Mackey Smith, 1975). The map also indicates the presence of advance and recessional outwash in the general area surrounding the site. Our site explorations encountered glacial till, recessional outwash, and fill. Glacial till, commonly referred to as "hardpan," is an unsorted mixture of sand, silt, and gravel that is deposited at the bottom of a continental glacier. As a result of having been consolidated under the weight of the .glacier, glacial till exhibits both high strength and low permeability. Alluvial sand and gravel deposited by glacial melt water during glacial recession is known as recessional outwash. In contrast to glacial till, recessional outwash has not been glacially consolidated. Explorations Subsurface conditions were explored at the site on December 28, 2004, by excavating a total of five test pits. The test pits were excavated to depths ranging between 0.5 and 11.0 feet below the ground surface: The explorations were located in the field by a representative from this firm who also examined the soils and geologic conditions encountered, and maintained logs of the test pits. The approximate locations of the test pits are shown on the Site Plan in Figure 2: The soils were visually classified in general accordance with the Unified Soil Classification System, a copy of which is presented as Figure 3. The logs of the test pits are presented in Figures 4 and 5. Subsurface Conditions A brief description of the conditions encountered in our explorations is included below. For a more detailed description of the soils encountered, review the test pit logs in Figures 4 and 5. Cornerstone Geotechnical, Inc. Geotechnical Engineering Report Meadowdale Estates Edmonds, Washington January 6, 2005 CG File No. 1791 Page 4 Our explorations encountered glacial till, recessional outwash, and fill. Test Pits 3, 4 and 5 were excavated in cut areas and all encountered very dense till within one foot of the surface. Test Pits 1 and 2 encountered approximately 4.0 and 5.0 feet of fill, respectively. Beneath the fill, Test Pit 1 encountered recessional outwash. Test Pit 2 encountered a layer of topsoil underlying the fill. The topsoil layer was underlain by weathered glacial till becoming glacial till. It should be noted that loose soils in the areas of: Test Pits 1 and 2 extend at least 4.G and 6.0 feet below the ground surface, respectively. Hydrologic Conditions r k Shallow ground water seepage was encountered in Test Pit 2 ata depth of approximately 1.0 foot. We consider this water to be perched, and associated with surface runoff_ The on-site till, in particular, is considered poorly draining. During the wetter times of the year, we expect perched water conditions will occur as pockets of water on top of the till layer. Perched water does not represent a regional ground water "table" within the upper soil horizons. Volumes of perched ground water vary depending upon the time of year and the upslope recharge conditions. Erosion Hazard The erosion hazard criteria used for determination of affected areas includes soil type, slope gradient, vegetation cover, and ground water conditions.' The erosion sensitivity is related to vegetative cover and the specific surface soil types (group classification), which are related to the underlying geologic soil units. The Soil Survey of Snohomish County Area Washington by the Soil Conservation Service (SCS) was reviewed to determine the erosion hazard of the on-site soils. The site surface soils were classified using the SCS classification system as Unit 5 (AIderwood — Urban Land Complex). The corresponding geologic unit for these soils is till, which is generally in agreement with the soils encountered in our site explorations. The erosion hazard for the soil is listed as being slight for slopes less than 8 percent. The moderately -sloping portions of the site may encounter higher levels of erosion, but not to such a degree that the site would be classified an erosion hazard. Best management practices (BMPs) and applicable codes should be followed during site grading to limit potential for erosion. We do not expect this site will require unusual or extreme erosion management methods. There are no water bodies adjacent to the site. Cornerstone Geotechnical, lnc. Geotechnical Engineering Report 1VMeadowdale Estates Edmonds, Washington January 6, 2005 CG File No. 1791 Page 5 Seismic Hazard The site is classified based on its overall soil profile using Table 1615.1.1 of the 2003 International Building Code (iBC). Site conditions :best fit%the IBC definition for Site Class C ("Very dense soil and soft rock"). The IBC provides parameters and coefficients to be used in seismic design based upon this site class. Additional seismic considerations include Iiquefaction potential and amplification of ground motions by soft soil deposits. The liquefaction potential is highest for loose sand with a high ground water table. The underlying dense till is considered to have a:very low potential for liquefaction and amplification of ground motion. CONCLUSIONS AND RECOMMENDATIONS General It is our opinion that the site is compatible with the planned development. The underlying medium dense to very dense glacial till deposits are capable of supporting the planned structures and pavements. We recommend that the foundations for the structures extend through any topsoil, fill, loose, or disturbed soils, and bear on the underlying medium dense to very dense, native glacial till, or on structural fill extending to these soils. Based on our explorations, we anticipate these soils will generally be encountered at typical footing depths in the cut areas of the site_ Fill encountered in Test Pits I and 2 was loose. As a result, areas of fill may need to be over -excavated and properly compacted. Alternatively, foundations could be constructed to extend through the loose soils. The soils likely to be exposed during construction are highly moisture sensitive and will disturb easily when wet or during wet conditions. We recommend that construction take place during the drier summer months, if possible_ If construction takes place during the wet season, additional expenses and delays should be expected due to the wet conditions. Site Preparations and Grading The first step of site preparation should be to strip the vegetation, topsoil, or loose soils to expose medium dense to very dense native soils in pavement and building areas. This material should be removed from the site, or stockpiled for later use as landscaping fill. The resulting subgrade should be compacted to a Cornerstone Geotechnical, Inc. .Geotechnical Engineering Report Meadowdale Estates Edmonds, Washington January 6, 2005 CG File No. 1791 Page 6 firm, non -yielding condition. Areas observed to pump or weave should be repaired prior to placing hard surfaces. The on-site glacial till likely to be exposed during construction is considered highly moisture sensitive, and the surface will disturb easily when wet. We expect these soils would be difficult, if not impossible, to compact to structural fill specifications in wet weather. We recommend that earthwork be conducted during the drier months. Additional expenses of wet weather or winter construction would include extra excavation and use .of imported fill or rock spalls. Structural Fill General: All fill placed beneath buildings, pavements or other settlement sensitive features should be placed as structural fill. Structural fill, by definition, is placed in accordance with prescribed methods and standards, and is monitored by an experienced geotechnical professional or soils technician. Field - monitoring procedures would include the performance of a representative number of in-place density tests to document the attainment of the desired degree of relative compaction. Materials: Imported structural fill should consist of a good quality, free -draining granular soil, free of organics and .other deleterious material, and be well graded to a maximum size of about 3 inches.. Imported, all-weather structural fill should contain no more than 5 percent fines (soil finer than a Standard U.S. No. 200 sieve), based on that fraction passing the U.S. 3/4 -inch sieve. The use of on-site soil as structural file will be dependent on moisture content control. Some drying of the native soils may be necessary in order to achieve compaction. During wam-4 sunny days this could be accomplished by spreading the material in thin lifts and compacting. Some aeration and/or addition of moisture may also be necessary. We expect that compaction of the native soils to structural fill specifications would be difficult, if not impossible, during wet weather_ Fill Placement: Following subgrade preparation, placement of the structural fill may proceed. Fill should be placed in 8- to 10 -inch -thick uniform lifts, and each lift should be spread evenly and be thoroughly compacted prior to placement of subsequent lifts. All structural fill underlying building areas, and within a depth of 2 feet below pavement and sidewalk subgrade, should be compacted to at least 95 percent of its maximum dry density. Maximum dry density, in this report„refers to that density as Cornerstone Geotechnical, Inc. Geotechnical Engineering Report Meadowdale Estates Edmonds, Washington January 6, 2005 CG File No. 1791 Page 7 determined by the ASTM D 1557 compaction test procedure. Fill more than 2 feet beneath sidewalks and. pavement subgrades should be compacted to at least 90 percent of the maximum dry density. The moisture content of the soil to be compacted should be within about 2 percent of optimum so that a readily corapactable condition exists. It may be necessary to overexcavate and remove wet surficial soils in cases where drying to a compactable condition is not feasible. All compaction should be accomplished by equipment of a type and size sufficient to attain the desired degree of compaction. Temporary and Permanent Slopes Temporary cut slope stability is a function of many factors, such as the type and consistency of soils, depth of the cut, surcharge loads adjacent to the excavation, length of time a cut remains open, and the presence of surface or ground water. It is exceedingly difficult under these variable conditions to estimate a stable temporary cut slope geometry. Therefore, it should be the responsibility of the contractor to maintain safe slope configurations, since the contractor is continuously at the job site, able to observe the nature and condition of the cut slopes, and able to monitor the subsurface materials and ground water conditions encountered. We anticipate cuts for the daylight basements of your proposed residences. For planning purposes, we recommend that temporary cuts in the near -surface weathered soils be no greater than IH:IV- Cuts in the fill should be no greater than 1.5H:IV. Cuts in the dense to very dense till may stand at a 0.75H:1V inclination or possibly steeper. If ground water seepage is encountered, we would expect that flatter inclinations would be necessary. We recommend that cut slopes be protected from erosion. Measures taken may include covering cut slopes with plastic sheeting and diverting surface runoff away from the top of cut slopes. We do not recommend vertical slopes for cuts deeper than 4 feet, if worker access is necessary. We recommend that cut slope heights and inclinations conform to local and. WISHA/OSHA standards. Final slope inclinations for structural fill and the cuts in the native soils should be no steeper than 2H:1 V. Lightly compacted fills or common fills should be no steeper than 3H:IV. Common fills are defined as fill material with some organics that are "trackrolled" into place. They would not meet the compaction specification of structural fill. Final slopes should be vegetated and covered with straw or jute netting. The vegetation should be maintained until it is established. Cornerstone Geotechnical, Inc. Geotechnical Engineering Report Meadowdale Estates Edmonds, Washington January 6, 2005 CG File No. 1791 Page 8 Foundations Conventional shallow spread foundations should be founded on undisturbed, medium dense to very dense, glacial till, or be supported on structural fill extending to those soils. If -the soil at the planned bottom of footing elevation is not medium dense to very dense, it should be overexcavated to expose suitable bearing soil, and the excavation should be filled with structural fill, or the footing may be overpoured with extra concrete. For residences planned to be built on sloping ground, we recommend a minimum horizontal distance of 10 feet between the bottom of the footing and the slope face. Footings should extend at least 18 inches below the lowest adjacent finished ground surface for frost protection and bearing capacity considerations_ Minimum foundation widths of 16 and 20 inches should be used for continuous and isolated spread footings, respectively. Standing water should not be allowed to accumulate in footing trenches. All loose or disturbed soil should be removed from the foundation excavation prior to placing concrete. For foundations constructed as outlined above, we recommend an allowable design bearing pressure of 2,000 pounds per square foot (psf) be used for the footing design. International Building Code (IBC) guidelines should be followed when considering short-term transitory wind or seismic loads. Potential foundation settlement using the recommended allowable bearing pressure is estimated to be less than 1 - inch total and V? -inch differential between footings or across a distance of about 30 feet. Higher soil bearing values may appropriate for footings founded on the unweathered till, and with wider footings. These higher values can be determined after a review of a specific design. Lateral loads can be resisted by friction between the foundation and subgrade soil, and by passive soil resistance acting on the below -grade portion of the foundation. For the latter, the foundation must be poured "neat" against undisturbed soil or backfilled with clean, free -draining, compacted structural fill. Passive resistance may be calculated as a triangular equivalentfluid pressure distribution_ We recommend that an equivalent fluid density of 225 pounds per cubic foot (pef) be used to calculate the allowable lateral passive resistance for the case of a level ground surface adjacent to the footing. An allowable coefficient of friction between footings and soil of 0.45 may be used, and should be applied to the vertical dead load only. A factor of safety of 2.0 has been applied to the passive pressure to account for required movements to generate these pressures. The friction coefficient does not include a factor of safety. Cornerstone Geotechnical, Inc. Geotechnical Engineering Report 'Meadowdale Estates Edmonds, Washington January 6, 2005 CG File No. 1791 Page 9 Lateral Loads The lateral earth pressure acting on retaining walls is dependent on the nature and density of the soil behind the wall, the amount of lateral wall movement that can occur as backfill is placed, and the inclination of the backfill. Walls that are free to yield at least one -thousandth of the height of the wall are in an "active" condition. Walls restrained from movement by stiffness or bracing are in ars "at -rest" condition. Active earth pressure and at -rest earth pressure can be calculated based on equivalent. fluid density. Equivalent fluid densities for active and at --rest earth pressure of 35 pounds per cubic foot (pcf) and 55 pcf, respectively, may be used for design for a level backslope. Equivalent fluid densities for active and at -rest earth pressure of 45 pounds per cubic foot (pcf) and 75 pcf, respectively, may be used for design for a 20 degree backslope. These values assume that the on-site soils are used for backfill, and that the wall backfill is drained. The preceding values do not include the effects of surcharges due to foundation loads, traffic or other surface loads. Surcharge effects should be considered where appropriate. The above lateral pressures my be resisted by friction at the base of the wall and passive resistance against the foundation. A coefficient of friction of 0.45 may be used to determine the base friction when supported on the above recommended foundation subgrade preparation alternatives. An equivalent fluid density of 225 pcf should be used for passive resistance. The friction value does not incorporate a safety factor. A safety factor of 2 is applied to the passive pressure to limit movement. All wall backfill should be well compacted. Care should betaken to prevent the buildup of excess lateral soil pressures due to overcompaction of the wall backfill. This can be accomplished by placing wall backfill in 8 -inch loose Iifts and compacting with small, band -operated compactors. Slabs -On -Grade Slab -on -grade areas should be prepared as recommended in the Site Preparation and Grading subsection_ Slabs should be supported on medium dense to very dense native soils, or on structural fill extending to these soils. Where moisture control is a concern, we recommend that slabs be underlain by 6 inches of free -draining coarse sand or pea gravel for use as a capillary break. A suitable vapor barrier, such as heavy plastic sheeting, should be placed over the capillary break. Cornerstone Geotechnical, Inc. Geotechnical Engineering Report 'Meadowdale Estates Edmonds, Washington January 6, 2005 CG File No. 1791 Page 10 Drainage Werecommend that runoff from impervious surfaces, such as roofs, driveway and access roadways, be collected and routed to an appropriate storm water discharge system. Final site grades should allow for drainage away from any buildings. We suggest that the finished ground surface be sloped at a gradient of 3 percent minimum for a distance of at least 10 feet away from the buildings. Surface water should be collected by permanent catch basins and drain lines, and be discharged into a storm drain system. We recommend that footing drains be used around all of the structures where moisture control is important. The underlying till will pond water that accumulates in the crawl space. It is .good practice to use footing drains installed at least 1 foot below the planned finished floor slab or crawl space elevation to provide drainage for the crawl space. At a minimum, the crawl space should be sloped to drain to an outlet tied to the drainage system. If drains are omitted around slab -on -grade floors where moisture control is important, the slab should be a minimum of 1 foot above surrounding grades. Where used, footing drains should consist of 4 -inch -diameter, perforated PVC pipe that is surrounded by free -draining material, such as pea gravel. Footing drains should discharge into tightlines leading to an appropriate collection and discharge point. Crawl spaces should be sloped to drain, and a positive connection should be made into the foundation drainage system. For slabs -on -grade, a drainage path should be provided from the capillary break material to the footing drain system. Roof drains should not be connected to wall or footing drains_ MONITORING We should be retained to provide monitoring and consultation services during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, and to provide recommendations for design changes, should the conditions revealed during the work differ from those anticipated. USE OF THIS REPORT We have prepared this report for Hoover Premier Homes and their agents, for use in planning and design of this project. The data and report should be pro -tided to prospective contractors for their bidding and Cornerstone Geotechnical, Inc. Geotechnical Engineering Report -Meadowdale Estates Edmonds, Washington January 6, 2005 CG File No. 1791 Page 11 estimating purposes, but our report, conclusions and -interpretations should not be construed as a warranty of subsurface conditions. The scope of our work does not include. services related to construction safety precautions, and our recommendations are not intended to direct the contractors' methods, techniques, sequences or procedures, except as specifically described in our report, for consideration in design. There are possible variations in subsurface conditions. We recommend that project planning include contingencies in budget and schedule, should areas be found with conditions that vary from those described in this report. Within the limitations of scope, schedule and budget for our work, we have strived to take care that our work has been completed in accordance with generally accepted practices followed in this area at the time this report was prepared. No other conditions, expressed or implied, should be understood. Cornerstone Geotechnical, Inc. Geotechnical Engineering Report 'Meadowdale Estates Edmonds, Washington January 6, 2005 CG File No_ 1791 Page 12 We appreciate the opportunity to be of service to you. if there are any questions concerning this report or if we cart provide additional services, please call. Sincerely, Cornerstone Geotechnical, Inc. - Jeff Laub, LG Project Geologist 1 xplims 08f16/p1' Rick B. Powell, PE Principal PAO:JPL:RBP:nt Three Copies Submitted Five Figures Cornerstone Geotechnical, Inc. Vicinity Map I A B c D E F G H J 4, R 6 7 1 ....... . . . . . `10 1 41 Pal Project Site 2 18Tr yN 4 21 1 @1995 Thomas Bros. Maps Cornerstone Phone: (425) 844-1977 RH Hoover - Meadowdale Estates Fax: (425) 844-1987 0 Geotechnical Inc. File Number Figure 17625 -130th Ave NE, C-102 - WoodinVille, WA - 98072 1791 1 co CD CN C%j w x 0 a) L- 6 CIL (D CL < U) C) 4-1 z 0 LL W _0 11 cu C) C) (D CO CD (D a) 0 -0 tp S? w E mo CD 0 U) > Z —j 0 0 ------- 7-3�� 7 71T71 CD X, rl- Co. 177 J,' 'Vkl t lit co CO CD LO C%l 04 f CD pijv W x jEMS 0o U- m I 4 L U nz) 'M7 LU 1-r U) LU h E CL j 14 %�`y4 -Kz\' "x C-) cl) M 16m c cr) I A R7,W if" t U3 Unified Soil Classification System MAJOR DIVISIONS GROUP SYMBOL GROUP NAME COARSE - GRAVEL CLEAN GRAVEL GW WELL -GRADED GRAVEL, FINE TO COARSE GRAVEL GP POORLY -GRADED GRAVEL GRAINED MORE THAN 50% OF COARSE FRACTION GRAVEL WITH FINES GM SILTY GRAVEL SOILS RETAINED ON NO. 4. SIEVE GC CLAYEY GRAVEL MORE THAN 50% RETAINED ON number 200 SIEVE SAND CLEAN SAND SW WELL -GRADED SAND, FINE TO COARSE SAND SP POORLY -GRADED SAND MORE THAN 50% OF SAND COARSE FRACTION PASSES NO.4 SIEVE WITH FINES SM SILTY SAND SC CLAYEY SAND FINE - SILTAND CLAY INORGANIC ML SILT CL CLAY GRAINED LIQUID LIMIT LESS THAN 50% SOILS ORGANIC OL ORGANIC SILT, ORGANIC CLAY MORE THAN 50% PASSES NO. 200 SIEVEMH SILTAND CLAY INORGANIC SILT OF HIGH PLASTICITY, ELASTIC SILT CH CLAY OF HIGH PLASTICITY. FAT CLAY 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 Dry -Absence of moisture, dusty, dry visual examination of soil in general to the touch accordance with ASTM D 2488-83. 2) Soil classification using laboratory Moist- Damp, but no visible water tests is based on ASTM D 2487-83. Wet- Visible free water or saturated, 3) Descriptions of soil density or usually soil is obtained from consistency are based an below water table interpretation of blowcount data, visual appearance of soils, and/or test data. Cornerstone Phone: (425) 844-1977 Unified Soil Classification System Geotechnical, Inc. Fax: (425) 844-1987 17625 -130th Ave NE, C-102 • Woodinville, WA' 98072 Figure 3 DEPTH - TEST PIT ONE 0.0-3.0 3,0-4.0 4.0 -10.0 TEST PIT TWO 0.0 - 1.0 1.0-5.0 5.0-6.0 6.0-10.0 10.0-11.0 TEST PTT THREE 0.0-1.0 1.0-4.0 TEST PIT FOUR 0.0 = 0.5 LOG OF EXPLORATION USC SOIL DESCRIPTION SM GRAY -BROWN SILTY FINE TO COARSE SAND WITH GRAVEL (LOOSE, MOIST) (FILL) SM DARK -GRAY SILTY FINE TO COARSE SAND WITH TRACE GRAVEL AND ORGANICS (LOOSE, WET) (FILL) SM GRAY SILTY MEDIUM TO COARSE SAND WITH GRAVEL (LOOSE TO MEDIUM DENSE, WET) ,(RECESSIONAL OUTWASHIFILL?) SAMPLES WERE COLLECTED AT 3.5, 8.0 AND 10.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS ENCOUNTERED BETWEEN 0.0 AND 4.0 FEET TEST PIT WAS COMPLETED AT 10.0 FEET ON 12!28104 SM DARK BROWN TO BLACK SILTY SAND WITH GRAVEL (LOOSE, WET) (TOPSOILIDUFF) SM GRAY -BROWN SILTY FINE TO COARSE SAND WITH GRAVEL (LOOSE, WET) (FILL) SM DARK BROWN -TO BLACK SILTY SAND WITH GRAVEL AND ORGANICS (LOOSE, WET) (TOPSOIL) SM RED -BROWN SILTY FINE TO MEDIUM SAND WITH GRAVEL AND ROOTS (LOOSE TO MEDIUM DENSE; MOIST) (WEATHERED TILL) SM BROWN -GRAY SILTY FINE TO MEDIUM SAND WITH GRAVEL (DENSE, MOIST) (TILL) SAMPLES WERE COLLECTED AT 3.0, 5.0, 8.0 AND 11.0 FEET GROUND WATER SEEPAGE WAS ENCOUNTERED AT APPROXIMATELY 1.0 FEET SLIGHT TEST PIT CAVING WAS ENCOUNTERED BETWEEN 0.0 AND 6.0 FEET TEST PIT WAS COMPLETED AT 11.0 FEET ON 12/28/04 SM BROWN SILTY FINE TO MEDIUM SAND WITH GRAVEL (LOOSE, MOIST) (FILL) SNI GRAY. SILTY FINE TO MEDIUM SAND WITH GRAVEL (VERY DENSE, MOIST) (TILL) SAMPLE WAS COLLECTED AT 4.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 4.0 FEET ON 12/28/04 SM GRAY SILTY FINE TO MEDIUM SAND WITH GRAVEL (VERY DENSE, MOIST) (TILL) NO SAMPLE WAS COLLECTED GROUND WATER. SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 0.5 FEET ON 12/28/04 CORNERSTONE GEOTECHNICAL, INC. FILE NO 1781 FIGURE 4 LOG OF EXPLORATION DEPTH USC SOIL DESCRIPTION TEST PIT FIVE SM BROWN SILTY FINE TO MEDIUM SANT} WITH GRAVEL (LOOSE, MOIST) (FILL) 1.0-1.5 SM GRAY SILTY FINE TO MEDIUM SANT) WITH GRAVEL (VERY DENSE, MOIST) (TILL) NO SAMPLE WAS COLLECTED GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 1.5 FEET ON 12128/04 CORNERSTONE GEOTECHNICAL, INC. FILE NO 1731 FIGURE 6