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20060608Geo Report.pdfGEOTECHNICAL ENGINEERING EVALUATION HEATH RESIDENCE EDMONDS, WASHINGTON PREPARED FOR NIS. STACY HEATH M05 5 i 17 y �` i RECEIVED MAR 2 8 2006 DEVELOPMENT SERVIC r ES CTR. CITY OF :DMONDS NELSON GEOTECHNICAL I A AssociATEs, INC. NGA GEOTECHNICAL ENGINEEFZS & GEOLOGISTS 17311 —13e Avenue NE,A-500 Woodinville, WA 98072 (425) 486-1669 - (426) Fax 481-2510 November 16, 2005 Ms. Stacy Heath 8125 Frederick Place Edmonds, Washington 98020 Geotechnical Engineering Letter Heath Residence — New Deck Supports and Retaining wall Edmonds, WA NGA File No. 724605 Dear Ms. Heath: Snohomish County (425) 337-1669 Wenatchee/Chelan (609) 784-2756 IM (:�I_ 0 V'\- This letter summarizes our opinions and recommendations regarding foundation support for the planned deck located off the back of your residence, and replacing the timber retaining wall and landscape rockery below the deck at your residence located at 8125 Frederick Place in Edmonds, Washington. INTRODUCTION The site is located in a residential neighborhood north of Snohomish County Park in Edmonds, Washington. The site is situated along the northern side of Frederick Place near the end of the street. A moderately steep drainage ravine is located below the residence, which the City of Edmonds has classified as a Critical Area. Specifically, the critical areas associated with the site include; Potential Erosion Hazard, Potential Landslide Hazard,. and Perrinville Stream. We understand that the existing deck along the northeast side of the residence is cantilevered. Wooden posts are currently providing some temporary support for the deck, propped vertically and resting on a small, non -engineered timber retaining wall below the deck. This retaining wall is showing signs of lateral and possibly vertical movement. Project plans include replacing the old deck with a new deck, which will include vertical supports. Additionally, a new approximate 90-foot long retaining wall will be constructed along Geotechnical Engineering Letter Heath Residence — New Deck Supports and Retaining Wall NGA File No. 724605 November 16, 2005 Page 2 the top of slope above the drainage ravine, which will run in close proximity to the new deck supports. This new retaining wall will replace the existing timber wall and a landscaping rockery located below the deck. We have been retained to evaluate the site surface and subsurface soil conditions and provide recommendations for new deck support and retaining wall design and installation. SITE CONDITIONS Surface Conditions 'Me property slopes mildly to steeply down to the northeast and is covered with grass, trees, pavement, and is occupied by the existing residence. The site is bordered to the east and west by residential property, to the south by Fredrick Place Road, and to the north-northeast by a drainage ravine leading to Perrinville Stream. The subject deck and small retaining walls are located on the north-northeast side of the residence, along the top of the drainage ravine. We measured the slope inclination of this ravine at up to 26 degrees from the horizontal over its upper portions, and as steep as 38-degrees as it approaches Perrinville Stream. The site layout is shown on the Site Plan in Figure 2. The slope is vegetated with fern, blackberries, and mature cedar and pine trees. Some signs of surficial. slope movement are evident along the lower portions of the slope, including sloughing of material and bent coniferous trees. Small, tiered rockeries and pin -pile supported timber walls are tiered along the slope face over the upper portions of the slope. These rockeries would be considered landscaping walls, which are generally two -feet high, and appeared to have been constructed to retain the uphill side of an abandoned pathway leading to the stream. A tightlined PVC pipe interpreted to be a downspout drain discharges on the slope face below the landscape walls. The pipe outfall location is not armored, and erosion effects have exposed native sandy soils in this location. We did not observe any standing water or groundwater seepage on the site or site slopes during our visit. The existing site conditions, site topography, and interpreted subsurface conditions are presented as Cross Sections A -A' and B-B' in Figures 3 and 4, respectively. NELSON GEOTECHNICAL ASSOCIATES, INC. Geotechnical Engineering Letter Heath Residence — New Deck Supports and Retaining Wall NGA File No. 724605 November 16, 2005 Page 3 Subsurface Conditions Geology: The Geologic Mqp of Edmonds East and Part of the Edmonds West Quadrangles, Washington, by James P. Minard (1985) was reviewed for this site. The site and site vicinity are mapped as advance outwash (Qva) and transitional beds (Qtb). Advance outwash is deposited in front of an advancing glacier, and generally consists of sand with pebbles and some cobbles, with locally silty and oxidized areas. Transitional bed deposits underlie the advance outwash deposits, and typically consist mostly of silt, clay, and very fine sand. We explored the area of slope, retaining wall, and proposed deck footings on October 24, 2005 and October 31, 2005 with six hand -auger explorations. Above the timber retaining wall, our explorations encountered approximately 2.0 to 2.5 feet of loose, moist, dark brown fine to coarse sand with silt, roots, and trace gravel just below the ground surface. We interpreted this material to be undocumented fill. Underlying the loose, brown sand we encountered moist, orangish- brown fine to coarse sand with gravel and trace silt. We interpreted this deposit to be native advance outwash (Qva) in a medium dense to dense condition. Below the retaining wall, our explorations generally encountered 1.0 to 2.5 feet of dark brown, fine to coarse sand with silt, roots, and trace gravel just below the ground surface. We interpreted this material to be topsoil. Below the topsoil, we encountered moist, orangish-brown fine to coarse sand with gravel and trace silt. We interpreted this deposit to be native advance outwash (Qva), in a medium dense to dense condition. The logs of our hand -auger explorations presented as Fi res 6 and 7. ga Hydrologic Conditions Groundwater seepage was not encountered in our hand -auger explorations. We interpret the advance outwash (Qva) as a relatively free -draining deposit. It is likely that during the wetter times of the year surface water may infiltrate and become perched on top of the siltier or denser portions of the advance outwash deposit, or flow through the outwash sands and become perched on the Transitional beds (Qtb) inferred to underlie the outwash sands. NELSON GEOTECHNICAL ASSOCIATES, INC. Geotechnical Engineering Letter Heath Residence — New Deck Supports and Retaining Wall NGA File No. 724605 November 16, 2005 Page 4 SENSITIVE AREA EVALUATION Seismic Hazard We reviewed the 2003 International Building Code (IBC) for seismic site classification for this project. Since medium dense to dense soils were generally encountered underlying the site at depth, the site conditions best fit the MC description for Site Class D. Hazards associated with seismic activity include liquefaction potential and amplification of ground motion by soft deposits. Liquefaction is caused by a rise in pore pressures it) a loose, fine sand deposit beneath the groundwater table. It is our opinion that the advance outwash soils interpreted to underlie the site have a low potential for liquefaction or amplification of ground motion due to their generally dense condition and lack of groundwater. Erosion Hazard The erosion hazard criteria used for determination of affected areas includes soil type, slope gradient, vegetation cover, and groundwater conditions. The erosion sensitivity is related to vegetative cover and the specific surface soil types, which are related to the underlying geologic soil units. The on -site soils were found to consist of mostly sandy advance outwash, and on -site slopes were, inclined between 26 and 38 degrees. We consider the on -site soils to have a moderate erosion hazard in their current state, with a vegetative cover. However, the erosion hazard along the slope would be high if vegetation were cleared, or if surface water was allowed to flow uncontrolled over the slope. Landslide Hazard/Slope Stability The criteria used for evaluation of landslide hazards include soil type, slope gradient, and groundwater conditions. The slope below the planned retaining wall and new deck had an inclination of up to 38 degrees along its lower portions, and an inclination of about 26 degrees along the upper extent, closer to the development area. The core of the site slope is inferred to consist of dense advance outwash sand and Transitional beds. Relatively shallow failures as well as surficial erosion are natural processes and could be expected on the slope, However, these processes would be limited through the maintenance of a vegetative cover and appropriate drainage systems. It is our opinion that there is not a significant potential for deep-seated slope failures under current site conditions. Proper site grading and NELSON GEOTECHNICAL ASSOCIATES, INC. Geotechnical Engineering Letter Heath Residence — New Deck Supports and Retaining Wall NGA File No. 724605 November 16,2005 Page 5 drainage as well as vegetation management as recommended in this report should help maintain current stability conditions. Also, the addition of a drain behind the proposed retaining wall should help prevent storm water from flowing over the slope and should reduce potential impact of site development on the slope and vice versa. CONCLUSIONS AND RECOMNENDATIONS General It is our opinion from a geotechnical standpoint that the site is compatible with the planned development. Our explorations indicate that medium dense to dense outwash sand deposits generally underlie the site within the development area. These soils should provide adequate support for the planned deck supports and retaining wall. We recommend that the deck be designed using Sonotube pier foundation supports, Sonotube piers should extend through any loose surficial soil or fill and be founded on the medium dense to dense native soils. Sonotube piers should also extend below the base of the proposed retaining wall, and be installed no closer than three feet (horizontally) from the wall. For planning purposes, Sonotube piers installed to satisfy our design criteria should typically extend 5.0 to 7.0 feet below the existing surface. It would be most practical to install the Sonotube piers while the retaining wall excavation is open. This is discussed further in the Deck Support sub -section of this letter. It is our opinion, based on our discussions with your builder, that a reinforced Keystone block wall is most suitable for the development given the site conditions. The underlying medium dense or better native soils expected to be encountered in the wall subgrade should provide suitable support for the reinforced fill and Keystone block facing. We recommend that the wall and reinforced fill footprint be over -excavated down to the underlying medium dense or better native soil and the wall be supported on this material. Plans indicate that the wall will be about 90 feet long and have an exposed height of 3.5- to 4.5- feet. However, the total wall height may be up to six feet in order to satisfy a recommended base embedment of I 8-inches below finished ground surface. A temporary cut up to six feet in height for wall construction may expose loose soil or raveling sand materials that may not stand in a near -vertical geometry. The cut face will need to be sloped back for stability and worker access, NELSON GEOTECHNICAL ASSOCIATES, INC. Geotechnical Engineering Letter Heath Residence — New Deck Supports and Retaining WaH NGA File No. 724605 November 16, 2005 Page 6 Typically a 2 Horizontal to 1 Vertical (2H: 1V) temporary inclination would be required in such materials. However, if a 2H: 1V slope is not feasible for the temporary wall cut, near vertical cuts up to four feet in height separated by four -foot wide horizontal benches may be feasible. The appropriate slope treatment can be evaluated at the time of excavation for wall construction under the supervision of NGA. This is discussed further in the Wall Design and Construction Recommendations subsection of this letter. Erosion Control and Slope Protection The on -site soils can have a moderate to high potential for erosion, depending on how the site is graded and how water is allowed to concentrate. Best Management Practices (BMPs) should be used to control erosion. Areas disturbed during construction should be protected from erosion. Measures taken may include diverting surface water away from the stripped areas. Silt fences or straw bales should be erected to prevent muddy water from flowing over the site. slopes or the existing storm system. Disturbed areas should be replanted with vegetation at the end of construction. The vegetation should be maintained until established. Final grading should incorporate appropriate erosion control measures to route stormwater runoff away from the top of slope and to appropriate discharge locations. Runoff generated within the site, including roof downspouts, yard areas, and hard surfaces should be collected into catch basins and yard drains and tightlined into an approved stormwater management system. Under no circumstances should runoff be allowed to flow over the slope either during construction or after construction has been completed. Vegetation on the slopes should be maintained and not be disturbed. Future tree thinning or removal should be subject to a specific plan approved by the city. Future yard waste, grass clippings, or any waste material should not be cast over the slope or piled above the wall. Stockpiled materials should not be placed on or near the slope. Additionally, the PVC downspout drain currently outfalling on the slope face, and the drainpipe associated with the new Keystone wall, should both be extended to the slope bottom and armored with rockspalls. Deck Support We recommend that 12-inch diameter Sonotube piers be utilized to support the new deck. Sonotube piers, if adequately extended into compact native material, should provide suitable NELSON GEOTECHNICAL ASSOCIATES, INC. Geotechnical Engineering Letter Heath Residence — New Deck Supports and Retaining Wall NGA File No. 724605 November 16,2005 Page 7 vertical and lateral support for the deck posts. Sonotubes usually consist of rigid cardboard tubes that act as a permanent form for individual post supports. After the post footings are excavated to finished subgrade, the Sonotube forms are lowered into the excavations and the tubes are then filled with concrete. Because these tubes will be installed while the retaining wall excavation is open, there will likely be more of the tube length extending from the ground surface then embedded below it. It may be prudent for the contractor to brace the upper portions of the Sonotube during and shortly after pouring concrete. After the concrete is given time to cure, the backfill of the retaining wall excavation may continue. We recommend that the Sonotube forms be filled with structural concrete and extend a minimum of two feet into native competent soils. The Sonotubes could stick above finished grade by two to three feet to shorten the deck posts and reduce the potential for moisture contact with deck posts. Wall Design and Construction Recommendations The total height of the planned wall is expected to be up to 6 feet, including a n-tinimum. recommended embedment of 1.5-feet into native soils. We have provided a design for a 4- to 6- foot-high reinforced earth retaining wall with Keystone block facing. The wall detail and design parameters along with construction notes are shown on Figure 7. We have assumed that the retained and reinforced fill zones consist of granular material compacted to structural fill specifications. The backfill may be sloped at up to 14 degrees (existing average inclination of the side -yard), though we anticipate the fill will likely be placed near level to re -grade the top -of - slope. The drainage system, as indicated on the detail, should be installed along the base of the blocks and behind the Keystone facing. Stratagrid geogrid (or equivalent) is recommended in the wall design. The geogrid should be cut to the recommended lengths, attached to the blocks as recommended by the manufacturer, and extended back into the reinforced fill zone. The grid should be pulled tight before the fill is placed over the geogrid. Care should be taken not to damage the geogrid by operating construction equipment on the exposed grid, or by allowing large rock chunks to be placed directly on the grid. The grid should be oriented in the correct direction as geogrid strength varied, depending on the direction of the pull. NELSON GEOTECHNICAL ASSOCIATES, INC. Geotechnical Engineering Letter Heath Residence — New Deck Supports and Retaining Wall NGA File No. 724605 November 16, 2005 Page 8 The block facing should consist of Standard Keystone blocks. The block facing should be placed on a minimum of 4-inch thick crushed rock leveling pad placed over competent native soils. The subgrade should be compacted to a non -yielding condition before placing the blocks. A drainage blanket of 12 to 18 inches of free -draining crushed rock should be placed between the blocks and the reinforced earth zone. The block cavities should also be filled with the crushed rock. A rigid, perforated drainpipe embedded in a minimum of 1-foot of pea gravel and wrapped in a filter fabric should be placed at the bottom of the drainage blanket. The drain should be sloped to drain into a pen-nanent discharge point placed at the bottom of the slope. The Keystone blocks and reinforced fill should be placed on level pads excavated along the wall alignment. The reinforced fill design specifies layers of geogrid be placed with 2-feet of vertical separation in the reinforced fill, where multiple layers of geogrid are called for. Wall construction is simplified if the base of the wall excavation is also stepped in 2-foot increments so geogrid elevations are consistent along the complete length of the wall. The crushed rock leveling -pad can be used to fine grade this stepped excavation. Placement of geogrid behind the wall in the vicinity of the deck will require modifications due to the Sonotube piers, which will likely exist in the reinforced fill zone. After the reinforced fill zone has been compacted up to the elevation of the first geogrid layer, the geogrid should be sliced, then fit around each Sonotube and connected to the wall facing. Only the strands of geogrid which are running parallel to the wall facing should be clipped. Clipping should be minimized to the effect that the geogrid fits snug around each Sonotube. Alternatively, deck supports could be re -located outside of the reinforced fill zone, closer to the house. This would require cantilevering a portion of the new deck. The deck designer should be contacted if this is desirable. All fill placed in the reinforced fill zone and in the backslope above the retaining wall 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. The fill subgrade should consist of native medium dense or better native soil compacted to a non -yielding condition. NELSON GEOTECHNICAL ASSOCIATES, INC. Geotechnical Engineering Letter Heath Residence — New Deck Supports and Retaining Wall NGA File No. 724605 November 16,2005 Page 9 Structural fill should consist of a good quality, granular soil, free of organics and other deleterious material and be well -graded to a maximum size of about three inches. We should be retained to evaluate proposed fill material prior to construction. Following subgrade preparation, placement of structural fill may proceed. All fill placements should be accomplished in uniform lifts up to 10 inches thick. Each lift should be spread evenly and be thoroughly compacted prior to placement of subsequent lifts. All structural fill should be compacted to a minimum of 95 percent of the material's maximum dry density, Maximum dry density, in this report, refers to that density as determined by the ASTM D 1557 Compaction Test procedure. The moisture content of the soils to be compacted should be within about two percent of optimum so that a readily compactable condition exists. It may be necessary to over -excavate and remove wet 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. Wall design and details are presented as Figure 8. If ground water seepage is encountered or if excessive rainfall occurs during construction of specific aspects, we recommend that the contractor slope the bottom of the excavations and direct the water to ditches and small sump pits. The collected water can then be directed to a suitable discharge point at the bottom of the slope. USE OF THIS LETTER This letter has been prepared for Ms. Heath and her agents for use in the planning and redesign of the retaining wall and deck supports on this site only. 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 letter. There are possible variations in subsurface conditions between the explorations and also with time. Our letter, conclusions, and interpretations should not be construed as a warranty of subsurface conditions. A contingency for unanticipated conditions should be included in the budget and schedule. We recommend that NGA be retained to provide monitoring and consultation services during construction to confirm that the conditions encountered are consistent with those indicated by the NELSON GEOTECHNICAL ASSOCIATES, INC. Geotechnical Engineering Letter Heath Residence — New Deck Supports and Retaining Wall NGA File No. 724605 November 16, 2005 Page 10 explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether or not retaining wall and deck support installation complies with our recommendations. We should be contacted a minimum of one week prior to construction activities. All people who own or occupy homes on or near hillsides should realize that landslide movements are always a possibility. The landowner should periodically inspect the slope, especially after a winter storm. If distress is evident, a geotechnical engineer should be contacted for advice on remedial/preventative measures. The probability that landsliding will occur is substantially reduced by the proper maintenance of drainage control measures at the site (the runoff from the roofs should be led to an approved discharge point). Therefore, the homeowner should take responsibility for performing such maintenance. Consequently, we recommend that a copy of our report be provided to any future homeowners of the property if the home is sold. Within the limitations of scope, schedule and budget, our services have been perfon-ned in accordance with generally accepted geotechnical engineering practices in effect in this area at the time this letter was prepared. No other warranty, expressed or implied, is made. Our observations, findings, and opinions are a means to identify and reduce the inherent risks to the owner. NELSON GEOTECHNICAL ASSOCIATES, INC. Geotechnical Engineering Letter Heath Residence — New Deck Supports and Retaining Wall NGA File No. 724605 November 16, 2005 Page 11 We appreciate the opportunity to provide service to you on this project. If you have any questions or require further information, please call. Sincerely, NELSON GEOTECHNICAL ASSOCIATES, INC. mv��-M zd'�Ic- 104V�� Calvin A. McCaughan, EIT Staff Engineer 3521jVWAL I WIM Khaled Shawish, PE Principal CAM:KMS:Iam:kmn Three Copies submitted Eight Figures Attached I I' I �—Ds' NELSON GEOTECHNICAL ASSOCIATES, INC. VICINITY MAP Not to Scale Edmonds, WA I-rOjeCt NUmuer NELSON GEOTECHNICAL No. I Date I Revislon By ICK 724605 Heath Residence -- �NGA ASSOCIATrLs, INC. 11005 Original ACO EHK N 1 Vicinity Map GEOTECHNICAL ENGiNEERS & GEOLOGISTS Figure 1 17311-135th A— NE. A-M 4EW-lIlal W-d"la,WASW72 (42b� 486-16691 F- 481,2510 C9 —Z Existing Existing Timbei Retaining Wall A A' Approximate Location tof cross- section 0 40 80 Scale: 1 inch = 40 feet Reference: Site Plan based on an untitled, undated hand drawing prepared by Clayton Yakubow. Project Number NELSON GEOTECHNICAL 724605 Heath Residence �NG�A AsSOCIATES, INC. Site Plan GF-OYFCHNIr—AL ENGINEERS & GEOLOGISTS No. I Date I ReVision 1 11111105 1 Original Ely rCK ACO EHK Figure 2 1731�Xlh'.A: - E6t= -11, 11 &4W21r-1 W ffa 9 72 g:L 'WAN 704.2 (425) 4WIM9/ F-481-2510 —nb-gbxh=M _n —4 CD 0) Z 0 r_ Cr Southwest (D I 40 Existing Driveway rl 3: 30 HA-1 Existing Rockery ca a (to be replaced with :3 cD > :3 new Keystone Wall) 0 a) 26' Existing Rockeries and Timber Walls (retaining 0 20 uphill sides of overgrown Z > pathway) .0, W QVA :�a fp z > HA-2 r z M 10 38' z > F 00 0 Z Slope continues for > jo approximately 40 ft. win 0 to stream below 19? 0M o A z 8 wit a , 0, 30 40 70 10 io 50 60 > F Distance (feet) z Exploration 0 Test Pit Designation ---> TP-1 0 Groundwater Level During Exploration Geologic Contact (approximate) 0 Northeast . 40 Kill 20 10 IC NOTES: 1) Stratigraphic conditions are interpolated between the explorations. Actual conditions may vary. 2) Elevations are arbitrary. rn Reference. Cross Section is based on field measurements 1 200bX724605 HeathXCS.dwo a hand-held clinometer and I 00-ft tape measure. -n -4 CD 1-0 4�- FD (03 CZ 3 Cr Southwest t. Exisi -ing 40 -F Existing Residence Deck 40 0 (D 0 30 --30 Fill - CL 17* Existing Timber Retaining Wall (D A-5 (to be replaced with new (D Keystone Wall) 0 20 HA-3 --20 0, Z .4 inn LU QVA z > 38' r z r 10 --10 z > a V) M - i V) 0 in o z > M Slope continues for %% R? -10 M -1 ft.--" - approximately 40 - a V) In n 0 to stream below --0 urs! X 0 OZ 0 0 10 20 30 40 50 60 70 > r Exploration Distance (feet) z P Test Pit Designation ---> TP-1 0 f 3 NOTES: CL3. Groundwater Level --4 V 1) Stratigraphic conditions are interpolated between During Exploration the explorations. Actual conditions may vary. eologic Contact --> ? 2) Elevations are arbitrary. § �W (approximate) M X A X Reference: Cross Section is based on field measurements using a hand-held clinometer and 1 00-ft tape measure. 1 2005X724605 HeathICS.dwg _J UNIFIED SOIL CLASSIFICATION SYSTEM GROUP MAJOR DIVISIONS GROUP NAME SYMBOL CLEAN GW WELL -GRADED, FINE TO COARSE GRAVEL COARSE- GRAVEL GRAVEL GP POORLY -GRADED GRAVEL GRAINED MORE THAN 50 % GRAVEL GM OF COARSE FRACTION SILTY GRAVEL RETAINED ON SOILS NO. 4 SIEVE WITH FINES GC CLAYEY GRAVEL SAND CLEAN SW WELL -GRADED SAND, FINE TO COARSE SAND SAND SID POORLY GRADED SAND MORE THAN 50 % RETAINED ON MORE THAN 50 % NO. 200 SIEVE OF COARSE FRACTION SAND Sm SILTY SAND PASSES NO. 4 SIEVE WITH FINES SC CLAYEY SAND FINE - SILT AND CLAY ML SILT INORGANIC GRAINED LIQUID LIMIT CL CLAY LESS THAN 50 % SOILS ORGANIC OL ORGANIC SILT, ORGANIC CLAY SILT AND CLAY MH SILT OF HIGH PLASTICITY, ELASTIC SILT INORGANIC MORE THAN 50 % PASSES LIQUID LIMIT CH CLAY OF HIGH PLASTICITY, FLAT CLAY NO. 200 SIEVE 50 % OR MORE ORGANIC OH ORGANIC CLAY, ORGANIC SILT HIGHLY ORGANIC SOILS PT PEAT NOTES: I ) Field classification is based on visual SOIL MOISTURE MODIFIERS: examination of soil in general accordance with ASTM D 2488-93. Dry - Absence of moisture, dusty, dry to the touch 2) Sol[ classification using laboratory tests is based on ASTM D 2488-93. Moist - Damp, but no visible water. 3) Descriptions of soil density or Wet - Visible free water or saturated, consistency are based on usually soil is obtained from interpretation of blowcount data, be I ow water ta b le visual appearance of soils, and/or test data. Project Number NELSON GEOTECHNICAL No. Date I Revision By CK 724605 Heath Residence Soil Classification ASSOCIATES, INC. --'__�NGA GROTECHNICAL ENGINEERS & GEOLOGISTS 1 11M05 OriginEd ACO CAM Figure 5 17311-135th A- NE, MOO S.h­mh C-nty (425) W-1 569 WWd1nA6,WA08C72 (6 = 784-2756 f425) 4843-1669 1 F- 481 -25 ­nd-ng- — LOG OF EXPLORATION DEPTH (FEET) Usc SOIL DESCRIPTION HAND AUGER ONE 0.0-2.2 2.2-4.7 4�7 - 5.0 HAND AUGER TWO 0,0 - 4�O 4.0-6.0 6.0-6.3 HAND AUGER THREE 0.0-1.5 1.5-2.0 HAND AUGER FOUR 0.0-2.5 2.5-2.7 EHK:ACO DARK BROWN, FINE TO COARSE SAND WITH SILT, ORGANICS AND TRACE GRAVEL (LOOSE, MOIST) TOPSOIL SP ORANGISH-BROWN FINE TO COARSE SAND WITH TRACE SILT, TRACE GRAVEL AND TRACE ROOTS (MEDIUM DENSE, MOIST) SID ORANGISH-BROWN FINE TO COARSE SAND WITH GRAVEL (DENSE, MOIST) SAMPLES WERE COLLECTED AT 1-0, 2-5 AND 5-0 FEET GROUNDWATER SEEPAGE WAS NOT ENCOUNTERED HAND AUGER CAVING WAS NOT ENCOUNTERED HAND AUGER WAS COMPLETED AT 5.0 FEET ON 10/24105 RUSTY BROWN, FINE TO COARSE SAND WITH SILT, ORGANICS AND TRACE GRAVEL (LOOSE, MOIST) TOPSOIL SP ORANGISH-BROWN FINE TO COARSE SAND WITH TRACE SILT, TRACE GRAVEL AND TRACE ROOTS (MEDIUM DENSE, MOIST) SP ORANGISH-BROWN FINE TO COARSE SAND WITH GRAVEL (DENSE, MOIST) SAMPLES WERE COLLECTED AT 2.0, 4.8 AND 6.3 FEET GROUNDWATER SEEPAGE WAS NOT ENCOUNTERED HAND AUGER CAVING WAS NOT ENCOUNTERED HAND AUGER WAS COMPLETED AT 6.3 FEET ON 10124/05 DARK BROWN, FINE TO COARSE SAND WITH SILT, ORGANICS AND TRACE GRAVEL (LOOSE, MOIST) TOPSOIL SP ORANGISH-BROWN FINE TO COARSE SAND WITH TRACE SILT, TRACE GRAVEL AND TRACE ROOTS (MEDIUM DENSE, MOIST) SAMPLES WERE NOT COLLECTED GROUNDWATER SEEPAGE WAS NOT ENCOUNTERED HAND AUGER CAVING WAS NOT ENCOUNTERED HAND AUGER WAS COMPLETED AT 2.0 FEET ON 10/24/05 DARK BROWN, FINE TO COARSE SAND WITH SILT, ORGANICS AND TRACE GRAVEL (LOOSE, MOIST) TOPSOIL SP ORANGISH-BROWN FINE TO COARSE SAND WITH TRACE SILT, TRACE GRAVEL AND TRACE ROOTS (MEDIUM DENSE, MOIST) SAMPLES WERE NOT COLLECTED GROUNDWATER SEEPAGE WAS NOT ENCOUNTERED HAND AUGER CAVING WAS NOT ENCOUNTERED HAND AUGER WAS COMPLETED AT 2.7 FEET ON 10/24105 NELSON GEOTECHNICAL ASSOCIATES, INC. FILE NO 724605 FIGURE 6