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Subsurface and Geotechnical Report "I I J ] o AG R A Earth & Environmental n U 7 March 1996 6-917-108150 AGRA Earth & Environmental, Inc 11335 NE 122nd Way Suite 100 Kirkland v'iashingwn USA. 98034 69 8 Tel (206) 820-4669 Fax (206) 821-39 -+ J J '1 u n U Arch,tekton 12951 Bel-Red Road, Suite 110 Bellevue, Washington 98005 Attention Ms Angie Moffett Ii I LJ Subject Subsurface Exploration and Geotechnical Engineering Evaluation Texaco Gas Station Convenience Store Yelm, Washington fl U Dear Ms Moffett 'l , U n r U AGRA Earth & Environmental, Inc (AEE) is pleased to submit this report describing our recent geotechnical engineering evaluation for the above-referenced project The purpose of this evaluation was to evaluate general surface and subsurface site conditions, from which we could determine the feasibility of the project and formulate recommendations concerning site preparation, foundation design, and other constructIon considerations In accordance with our Proposal for Subsurface Exploration and Geotechnical Engineering Evaluation dated 22 February 1996, our scope of services consisted of a visual sIte reconnaissance, subsurface exploration, geotechnical analyses, and preparation of this report Our evaluation was limited to addressing site preparation, foundation design and pavement design, and does not specifically address underground storage tank mstallation This report has been prepared in accordance with generally accepted geotechnical engineering practice for the exclusive use of Texaco, Architekton, and their agents, for specific application to this project J n J n U J PROJECT DESCRIPTION The project site is located at 706 Yelm Avenue East in Yelm, Washington The triangular- shaped site is bounded by Yelm Avenue East to the south-southwest, multi-family residential property to the south-southeast, and 103rd Avenue to the north The 'attached Site and Exploration Plan (Figure 1) illustrates the subject parcel 'l , U II LJ We understand the development plans call demolition of the eXlstmg service station and the construction of a new facility including a convenience store, a six-island pump station, and a separate car wash building We antielpate that pavement will consist of both asphalt and concrete 1 u 'l J ~)~ ,. ' Engmeenng 8 EnVironmental Se0'lces II I U I) i U n , LJ Architekton 7 March 1996 6-917.108150 Page 2 n I LJ Ii I LJ It should be emphasized that the conclusions and recommendations contained in this report are based on our understanding of the currently proposed utilization of the project site, as presented in a layout plan which was obtained at the site from another consultant Consequently, If any changes are made in the project, we may need to modify our conclusions and recommendations to reflect those changes I] U n , , (J EXPLORATORY METHODS A representative of AEE evaluated surface and subsurface conditions at the project site on 23 February 1996 Our initial subsurface exploration program consisted of advancing two test pits (designated TP-1 and TP-2) at the approximate locations presented on the Site and Exploration Plan, to depths ranging from about 8 % to 9 % feet below existing grade Ii LJ J The specific number, locations, and depths of our explorations were selected based on the existing site features, proposed layout of the proposed facilIty, and limited use of a backhoe while it was at the site for D R Strong Consultmg Engmeers We estimated the location of each exploration by taping or pacing from site features and scaling these measurements onto a site plan provided to us As such, the exploration locations shown on the Site and Exploration Plan should be considered accurate only to the degree implied by our measuring methods II u n I U I) i U It should be emphasized that our explorations revealed subsurface conditions only at discrete locations across the project sIte and that actual conditions may vary between our exploration locations. Furthermore, the nature and extent of any such variations would not become evident until additional explorations are performed or construction activities have begun If sIgnificant variations are observed at that time, we may need to modify our conclusions and recommendations to reflect actual conditions For thIS reason, we recommend that AEE be retained to provide construction observation services dunng the foundation excavation phase of this project 'I LJ n U n LJ The test pits were completed with a backhoe operated by an independent firm working for AEE A geologist from our firm continuously observed the borings, logged the subsurface conditions, obtained representative soil samples, and transported the samples to our laboratory for further visual classification and testing After each test pit was completed, the pits were backfilled and tamped in place with the backhoe bucket The test pit backfill may require addItional compaetive effort at the time of construction n , LJ n LJ The attached test pit logs describe the various types of soils and materials encountered in each boring, based pnmanly on mterpretatlons made in the field Our logs also indicate the approximate depth of the contacts between different soli types, although these contacts may be gradational or undulating n J 'I , LJ n J @AGRA Earth & Environmental "I J n I LJ Architekton 7 March 1996 6-917-108150 Page 3 fl , I U n , u SITE CONDITIONS The following sections describe our observations, measurements, and interpretations concerning surface, soil, and groundwater conditions at the project sIte Interpretive logs of our explorations are attached to the end of this report 'l LJ n LJ Surface Conditions The project site appears to be on the order of 1 Y2 acres in size The topography of the site can be charactenzed as flat with topographic relief estimated to be on the order of 1 foot across the site Currently, the northwestern portion of the project site is occupied by the eXIsting Texaco station The southeastern portion of the site was cleared and was essentially bare of vegetation except for sparse bunch grass and weeds n J (1 , U Subsurface Conditions According to the U S D.A. Soil Conservation Service, Soil Survey of Thurston County, the near- surface geology at the project site is characterized by glacial outwash and volcanic ash deposits of unsorted sand, gravel, and silt These soils typically possess a moderate density and shear 1 strength, and relatively low compressibility The soils are categorized within Soil Hydrologic Group B which mdicates the soils have moderately high infiltration rate when wet with a low runoff potential n J n u n I U Based on the test pits completed for this project, the subsurface conditions appeared to be relatively uniform across the site It appears that the topsoil has already been removed from the area and the exposed surficial soils consist of a medium dense, dark brown to black, silty, gravelly, sand with varying proportions of cobbles This material typically extended to a depth of 2 to 2 Y2 feet Underneath, a dense, gravelly, cobbly, sand extended to a depth of 6 to 7 feet Below the dense soils, a medium, dense, fine sand with varying proportions of silt and gravel was encountered which extended to the full depths explored of 8 Y2 to 9 feet During excavation of the test pits, mmor caving of the sidewalls was observed Such caving should be expected in temporary cut sidewalls if the slope angles are oversteepened Temporary slope angle recommendations are presented subsequently ~ n I I U n I LJ n J We interpret these geological conditions to correspond to a seismic site coefficient Type S2, as defined by Table 16-J of the 1994 Uniform Building Code Soil profile type S2 applies where dense or stiff soil conditions exceed 200 feet in depth According to the 1994 Uniform Building Code's "Seismic Zone Map of the United States", the project site lies within Seismic Zone 3 fi U CONCLUSIONS AND RECOMMENDATIONS Current site development plans call for complete demolition of the existing service station structures and construction of a new station that will comprise a canopy, conerete apron, pump islands, convenience store, and car wash Our general conclusions and recommendations are as follows n J n J n LJ @AGRA Earth & Environmental r'l , , u J '1 LJ Architekton 7 March 1996 6-917-108150 Page 4 o Generally, subsurface conditions appear suitable from a geotechnical standpoint for the use of conventional shallow spread and continuous footings and slab-on-grade floors, contingent on proper subgrade preparation n J n \ LJ . Structural design of the buildings should conform to all requirements for seismic risk zone 3 and soil profile type 52' as prescribed by the 1994 Uniform Building Code n I LJ . The on-site native soils appear sUitable for reuse as structural fill n u Our specific recommendations concerning site preparation, excavations, temporary slopes, footings, slab-on-grade floors, drainage systems, and structural fill are presented in the following sections n J n U Site Preparation Initial site preparation will involve demolition of the eXisting structures, possibly removing existmg underground utilities and minor stripping of all vegetation and organIc-rich soils Any existing underground utilities, such as sewer lines, septic tanks, or drain lines, should be properly abandoned or removed and backfilled in accordance with appropriate governmental guidelines Similarly, any existing underground structures, such as foundation elements, should be removed and wasted from the site or recycled for reuse on the site In conjunction with this work, we recommend that any surface or near-surface water sources within the construction areas be intercepted and diverted to a suitable discharge location Final decisions regarding drainage systems are best made in the field at the time of construction by the general contractor n u n u n LJ n LJ Following site stripping and demolition, the site may be graded as required to establish appropriate subgrade elevations for the floors, concrete apron, and asphalt pavement areas Deeper holes or depressions created from removal of existing foundations, utilities, etc , should be backfilled with compacted structural fill prior to general site grading Our test pits indicate that the grading operation will most likely encounter primarily moist, medium-dense silty, gravelly sand After grading, all exposed subgrade soils should be proofrolled with a heavy roller or other suitable compaction equipment to achieve a firm, unyielding condition Grading may involve the placement of structural fill All structural fill should be compacted with the recommendations presented subsequently in this report n , u n J n U Any subgrade areas that exhibit excessive yielding or pumping should be scarified, aerated, and recompacted However, compaction of the near surface silty site soils should be attempted only when the soils are at, or very near, optimum moisture content (the moisture content that allows the greatest compacted soil density under a specified compactive effort), attempts to compact wet silty surficial solis will tend to cause degradation of the solis rather than an increase in densIty If the existmg soils are too wet to compact, they should be removed and If i U J n , U @ AG R A Earth & Environmental I , ~ l u Architekton 7 March 1996 6-91 7 -1 081 50 Page 5 n J n U replaced with compacted structural fill, as described in the Structural Fill section of this report Because these near-surface site soils are somewhat moisture-sensitive and susceptible to disturbance when wet, the contractor should minimize traffic over any prepared subgrades A working surface of well-graded sand and gravel (pit-run), crushed rock, or crushed recycled concrete may be needed to protect silty subgrades from unavOIdable traffic, If completed during extended wet weather periods J n n u Structural Fill Structural fill includes any fill materials placed under footings, slab-on-grade floors, concrete aprons, walkways, asphalt pavements, and other structures which require a firm and unyielding subgrade Typical materials used for structural fill include well-graded sand and gravel (pit-run), clean sand, crushed rock, quarry spalls, controlled-density fill (CDF), lean-mix concrete, crushed recycled concrete, and various soil mixtures of slit. sand, and gravel such as the native soils Aggregate fill should be placed in horizontal lifts not exceeding 8 inches in loose thickness, and each lift should be thoroughly compacted with a mechanical compactor Using the modified Proctor maximum dry density (ASTM 0- 1557) as a standard, we recommend that structural fill used for subgrades below the various types of on-site structures be compacted to the following densitIes : , u n u n J n LJ Subgrade Type Compaction 90 percent 90 percent 90 percent 95 percent 90 percent 95 percent 90 percent n Foundation Slab-on-grade floor Concrete walkway Asphalt pavement (upper 1 foot) Asphalt pavement (below 1 foot) Concrete apron (upper 1 foot) Concrete apron (below 1 foot) u rr , LJ n I LJ Regardless of material or location, all structural fill should be placed over firm, unyielding subgrades prepared In accordance with the Site Preparation section of this report Compaction should be verified by means of in-place density tests performed during fill placement In this way, the adequacy of soil compaction efforts may be evaluated as earthwork progresses n J n I U n 1 Soils used for structural fill should not contain Individual particles greater than about 6 inches in diameter and should contain less than % percent (by weight) organics, debriS, and other deleterious materials Given these prerequisites, the suitability of soils used for structural fill depends primarily on the grain-size distribution and moisture content of the soils when they are placed As the "fines" content (that soil fraction passing the U S No 200 sieve) increases, soils become more sensitive to small changes in moisture content Soils containing more than about 5 percent fines (by weight) cannot be consistently compacted to a firm. unyielding condition when the moisture eontent IS more than about 2 percentage pOints above optimum The use of "clean" soil will be necessary if fill placement proceeds during wet site conditions n J u 'l , LJ n , LJ @ AG R A Earth & Environmental 11 i u n I U Architekton 7 March 1996 6-917-108150 Page 6 n , U n J Clean soils are defined as granular sOlis that have a fines content of less than 5 pereent (by weight) based on the soil fractIon passing the U S No 4 sieve n In our opinion, the silty surficial sOIls encountered in the test pit excavations can be reused as structural fill if their moisture content is :t 2 percent of its optimum moisture content However, the fines content of these soils makes them somewhat moisture-sensitive and susceptible to disturbance when wet Consequently, they could be difficult or impossible to reuse during the winter and spring months. Even during the summer and fall, delays in grading could occur due to precipitation or the presence of uncontrolled surface water or groundwater If inclement weather occurs during earthwork, the upper wetted portion of the silty site soils may need to be scarified and allowed to dry, or they should be removed and replaced with clean granular fill or other suitable material n J u n LJ n J n U Utility Trenching and Backfilling We anticipate that utility trenching and backfilling will be performed concurrent with construction We recommend that installation conform to all applicable Federal, State, and I local regulations such as WISHA and OSHA regulations for open excavations n LJ In order to avoid compromising the support of existing utilities, we recommend that temporary excavations do not encroach upon the bearing sOils below existing utilities This bearing area should be considered to begin 3 feet away from the Widest point of the pipe, extending downward at a 1 Yz H 1 V or 1 H 1 V slope, depending on the relative density of the sOIls Medium dense soils should be cut at 1 Y2 H 1 V while dense soils may be cut at 1 H 1 V If, due to space constraints, an open excavation cannot be completed without encroaching on an existing utility, we recommend shoring the new utility excavation with a trench box or other suitable shoring system n J Il I U n We recommend that all utility subgrade soils be firm and unyielding and free of all soils which are loose, disturbed or pumping Such soils should be removed and replaced, if necessary All structural fill used to replace overexcavated soils should be compacted to a minimum of 90 percent of the modified Proctor soil maximum dry density per ASTM D-1557 u n I LJ n U After firm utility subgrades have been achieved, we recommend that a minimum of 6 inches of bedding material be placed in the trench bottom Bedding material for rigid and flexible pipe should conform with Sections 9-03 15 and 9-03 16, respectively, of the 1994 WSDOT/APWA Standard Specifications for Road, Bridge and MunicIpal Construction, or alternate materials depending on the pipe material We further recommend that all bedding materials extend at least 4 inches above utilities which require protection during subsequent trench backfilling All trenches should be wide enough to allow for compaction around the haunches of the pipe Otherwise, materials such as controlled density fill should be used to eliminate the mechanical compactIon reqUIred 1) J /f I U n u n , U o AG R A Earth & Environmental J 1 -l ,.., I U Architekton 7 March 1996 6-917-108150 Page 7 o n I LJ Backfilling the remainder of the trenches could be completed With on-site soils provided they can be compacted to the minimum levels specified All utility trench backfill should be compacted to at least the minimum levels recommended in the Structural Fill section of this report All stockpiled soils should be protected from wet weather conditions if they are intended for reuse as trench backfill If imported soils are required for trench backfill, we recommend they conform to WSDOT Specifications, Section 9-03 19, Bank Run Gravel for Trench Backfill, or be approved by AEE Finally, we recommend that AEE be retained to perform field inspections and density testing, as well as observe construction procedures n U J n I LJ Temporary Excavations and Slopes For planning purposes, we tentatively recommend that temporary cut slopes Within the medium dense, silty gravelly sand and underlying medium dense to dense sands and gravels be no steeper than 1 ~ H 1 V and 1 H 1 V (Horizontal Vertical) respectively, but flatter slopes may be necessary depending on environmental conditions All temporary slopes should be protected from erosion if the slopes are near streets, utilities, or structures whIch could be compromised due to undermining and loss of soil support n , ! u n J I LJ The stability of temporary excavation slopes is a function of many factors, including sOIl type, soil density, slope inclination, slope height, the presence of groundwater, and the duration of exposure Although excavations up to 4 feet deep are frequently made with near-vertical sides, the likelihood of bank failure increases as the cut is deepened and as the duration of exposure increases For this reason, temporary slope safety should remam the responsibility of the contractor, who is continually present at the site and is able to monitor the performance of the excavation and modify his activities to reflect varying conditions In all cases, cut-slope systems should conform to applicable governmental safety gUidelines n , I U n .f! J LJ Foundations Based on our explorations, it is our opinion that conventional spread and continuous footings will provide adequate support for the proposed structures if proper subgrade conditions are established We recommend that all footings bear either directly on recompacted existing soils, or on a prism of new structural fill placed above existing soils The following conclusions, recommendations, and considerations are presented for purposes of footing design and construction n I U n , n I LJ i U . If the existing soils are near optimum moisture content at the time of earthwork, we recommend that the upper 1 foot of subgrade soil below the footmgs be recompacted to at least 90 percent of the modified Proctor maximum dry density (ASTM D- 1557) In contrast, if the moisture content of these SOils is too high to allow compaction, we recommend that the upper 1 foot of soil below the footings be overexcavated and replaced With structural fill compacted to at least 90 percent of the modified Proctor maximum dry density In either case, the n J n r/ U n , U o AG R A Earth & Environmental Slab-Dn-Grade Floors In our opinion, based on our explorations, slab-on-grade floors can be used in the proposed sales building and car wash if proper subgrade conditions are established To minimize settlement and associated cracking, we recommend that all slabs bear either directly on umformly firm, unyielding, non-organic, existing soils or on structural fill placed over such native soils In either case, the floor subgrade areas should be prepared as described in the Site Preparation section of this report, the upper 6 inches of materials immediately below the floor slabs should consist of the following layers (top to bottom) I J n U Architekton 7 March 1996 n L1 n , , U n J n J n U n J /1 LJ n I U n U n J n \ U n I LJ II I LJ n J n I LJ n I LJ Ii \ LJ 6-917-108150 Page 8 pnsm of recompacted native soil or compacted fill soil should extend outward from each edge of the footing a minimum distance of 1 foot . Under no circumstances should footings be constructed atop loose, soft, or frozen sOIl, slough, debris, existing uncontrolled fill, or surfaces covered by standing water . Footings that bear on properly prepared subgrade sOils can be designed for a maximum allowable soil bearing pressure of 2500 pounds per square foot (psf) This allowable beanng pressure may be increased by one-third for short-term wind or seismic loading . For frost protection, exterior footings should penetrate at least 18 inches below adjacent outside grade, whereas interior footings need extend only 12 inches below adjacent grade or surrounding slab surface level Continuous and isolated footings should be at least 18 and 24 inches wide, respectively . We estimate that the total settlement of properly sized footings bearing on properly prepared subgrades may approach Yz inch, with differential settlement also on the order of Yz inch . We recommend using an allowable foundation base friction value of 0 35 and a maximum allowable passive earth pressure of 300 pcf, eqUIvalent fluid pressures Passive earth pressure resistance should be neglected on that portion of foundation elements within 1 foot of finished grade Structural fill placed around foundation elements which are designed to develop passive resistance should be compacted to a minimum of 90 percent of the modified Proctor maximum dry density . In our opinion, Type II, cement would be suitable for all concrete which is exposed to earth o AG R A Earth & Environmental n , L.J n I U Architekton 7 March 1996 n I LJ n , L.J n LJ n u Il i U 6-91 7 -1081 50 Page 9 . A 2-inch-thick curing -course of clean sand to allow proper curing of the concrete slab and to protect the vapor barrier, . A vapor barrier of plastic sheeting (such as Visqueen) to prevent the upward migration of ground moisture, and . A 4-inch-thick capillary break layer consisting of pea gravel or coarse sand and gravel to retard the upward wicking of ground moisture Capillary break material should contain less than 3 percent fines passing the U S #200 sieve, no more than 10 percent fine sand, and at lest 50 percent retained on the U S #4 sieve, with no aggregate larger than 1 inch n J Any structural fill used under the capillary break layer should be placed and compacted to at least 90 percent of the modified Proctor maximum dry density (ASTM D-1557), as described in the Structural Fill section of this report n Drainage Systems Given the type of soils underlying the site, it is our opinion that a permanent footing drainage system around the new bUilding is not necessary provided the recommended vapor barrier IS installed Our specific design recommendations are as follows u II I LJ f) U '1 i L.J n , u n , U n ~ n LJ . Roof-runoff and surface-runoff water should discharge into tightline pipes and be routed to a catch basin or other sUitable discharge location Under no circumstances should roof-runoff and surface-runoff water be allowed to discharge into the footing drain systems \ . Final site grades should be sloped downward away from the building so that runoff will flow by gravity to a suitable collection pOint, rather than ponding adjacent to the completed building Ideally, the area immediately surrounding the buIldings would be capped with an impermeable material such as concrete or asphalt to preclude surface water infiltration . If the building is surrounded by a perimeter footing drain system to collect seepage water This footing drain should consist of a 4-inch diameter perforated pipe within an envelope of pea gravel or washed rock extending at least 6 inches on all sides of the pipe Pea gravel or washed rock should be sized appropriately to prevent migration through the perforations in the drain pipes Pavement Design Recommendations Based on our explorations, we expect that the pavement subgrade will consist of medlum- dense, silty gravelly sand Before paving begins, this subgrade should be proofrolled to a firm, unyielding conditIon, then proof-rolled with a loaded dumptruck to verify the compaction Any II U n I U II , u OAGRA Earth & Environmental -, --1 , u n LJ Architekton 7 March 1996 6-917-108150 Page 10 n I LJ soft, yielding areas disclosed dunng the proof-rolling operation should be excavated and replaced with a sUItable structural fill material compacted according to the recommendations given in the "Structural Fill" section of our previous report Specifically, the upper 1 foot of subgrade soils should be compacted to at least 95 percent of the modified Proctor maximum dry density (ASTM 0- 1557), and all other solis should be compacted to at least 90 percent It should be noted, however, that most of the on-site soils will be difficult to compact during the wet season, due to their high silt contents 11 , , u fI , U Critical features that govern the durability of a pavement section include the stabIlity of the subgrade, the presence or absence of moisture, free water, and organics, the fines content of the subgrade soils, the traffic volume, and the frequency of use by heavy vehicles Soil conditions can be defined by a California Bearing RatIo (CBR), and traffic conditions can be defined by a Traffic Index (TI) Based on our experience with similar soils, we estimate that the on-site soils will provide a CBR value on the order of 25 percent We have also assumed a TI value of 5 0 for the paved areas, which corresponds to traffic conditions involving frequent passes by cars and occasional passes by tanker trucks Using these design criteria, we recommend the following minimum pavement section n LJ if U (l I U 11 I U Pavement Course Minimum Thickness f' Asphalt Concrete Pavement Crushed Rock Base Granular Subbase 2 Y'2 inches 4 Inches o inches , LJ .11 For the base course, we recommend the use of imported, clean, uniform, %-inch minus crushed rock similar to that specified in the 1994 DOT Standard Specifications for Road, Bridge and Municipal Construction, Section 9-03 9(3) Crushed Surfacing, Top Course Alternatively, pulverized asphalt or concrete derived from off-site sources could be used, provided that it has a similar particle gradation and durability characteristics. All base course and subgrade materral should be compacted to at least 95 percent of the modified Proctor maximum dry density (ASTM 0-1557) as described in the "Structural Fill" section of our previous report u f' LJ (I LJ n It should be emphasized that no asphaltic pavement is maintenance-free The above-described pavement section represents our minimum recommendatIon for an average level of performance during a 20-year design life, therefore, an average level of maintenance will likely be required Selection of the actual pavement section should be based on the desired pavement performance and on economic considerations Thicker asphalt and base courses would offer better long-term performance, but would cost more initially, thinner pavement courses would be more susceptible to "alligator" cracking and other failure modes As such, pavement design can be considered as a compromise between a high initial cost and low maintenance costs versus a low initial cost and high maintenance costs u 'I u n u " u I) LJ o AG R A Earth & Environmental 'I -! '1 u Architekton 7 March 1996 6-917-108150 Page 11 n L1 If LJ For concrete pavement sections, we recommend a minimum 6 inch thick slab over 6 Inches of crushed gravel Furthermore, we recommend that the concrete have a minimum rupture modulus (flexural strength) of at least 500 psi n i LJ (, , CLOSURE The conclusions and recommendations presented in thIs report are based, In part, on the explorations accomplished for this study If significant variations in subsurface conditions are later discovered, we may need to revise our report Because the future performance and integrity of the foundations and the success of the earthwork depend largely on proper initial site preparation, drainage, and construction procedures, monitoring by experienced geotechnical personnel should be considered an integral part of the construction process We are available to review any design plans and specifications, and to monitor the earthwork and foundation construction phases of the project. If variations in the subgrade conditions are observed at that time, we would be able to provide additional geotechnical recommendatIons to minimize delays as the project develops AEE can also provide testing and inspection of concrete and reinforcing steel throughout construction 1"\ I U Il J n U u LJ We appreciate the opportunity to be of service on this project Should you have any questions regarding this report or any aspects of the project, please do not hesitate to call Respectfully submitted, ~~~"ll! (V' ~~S A. if. t<9 \\~ W ASIjJ: O.tV < AGRA Earth & Environme t,~.,~, tc .;---;~~ <'VQ_~to ~..: h',.~~""",,-,~, ,'., E-, I t 0 ,'J4 ;~~/~ <. Z\ " .....,., C\. , ..0 ....; I 2~:v~ ~l" ~ v '+..., -::~9 f..ti !'f1 o .1'" <. /"'I"Y'" 6'>~ "~''Cir ,." '<';> r ~ ~(. _._ ~~o .,-.lV.. .<,\: .. ...,. "':J"'n;~:'~'i::;"":-S "':;" 'l U n LJ n LJ n Thomas A. Jones, P E Senior Project Engineer u rr LJ "l , U I Kurt D Merriman, P E Associate n T AJ/KDM/caj n I U Enclosures Site & Exploration Plan, Figure 1 Test Pit Logs TP-1 and TP-2 'l LJ n u OAGRA Earth & Environmental VELM AVENUE EAST {STATE ROAD 507} j J \J Q Q Q Q U Q Q 0 U U Q Q ,,; := i C .. n E c 0 PUMP ISLANDS ~ ~ ~ ~ 11 LJ ~ PARKING (TVP ) (--.... .....-- .....------.. , l PROPOSED SALES BUILDING \ \ \ TP-2 S ,~ TP-1 I ~ '-_-----------J 000 UNDERGROUND STORAGE TANKS 000 0 o ,,=," ~<(",. !t' ~O ~<v ~<v~ ~ r':J'o ,,0 . AGRA earth & Environmental 11335 NE 122nd Way, suite 100 Kirkland, washington. U SA 98034-6918 LEGEND TP-2 .~ TEST PIT NUMBER AND APPROXIMATE LOCATION o 4-0 BO ~r~- - SCALE IN fn:.i VEL'" TEXACO VELy':WAS,",ltlGTON - W.o.~ DESIGN ..w--- DRAWN ~ DAiE ~ SCALE ~ ,- SITE. EX.,LQI.\ATlON PLAN fIGURE 1 n u n u n ~ 11 I U Deoth (feet) (I LJ 11 u 00-20 (I I u 20-60 11 60-85 LJ n LJ n u '1 LJ II 00-25 LJ n 25-70 u 70-90 n L.J n u f' u TEST PIT LOGS Material Descriotion Test Pit TP- 1 Location Approximate ground surface elevation feet/Unknown Medium dense, moist, black, silty gravelly fine to medium SAND, some cobbles, minor organics Dense, moist, brown, gravelly, cobbly fine to medium SAND Rounded cobbles to 10-inch diameter, trace-source silt. Medium dense, moist, brown, fine SAND, trace-source silt. Test pit terminated at approximately 8 5 feet Minor caving at ~ feet No seepage observed Test Pit TP-2 Location Approximate ground surface elevation feet/Unknown Medium dense moist, black silty gravelly fine to medium SAND Minor organics Dense, moist, brown gravelly cobbly fine to medium SAND Some cobbles to a-inch diameter, trace-source silt. Medium dense, moist, brown fine SAND Some rounded gravel, trace silt. Test pit terminated at approximately 9 feet Minor caving at _ feet No seepage observed n Date excavated 23 February 1996 Logg~d by C Cacek u !Il u n , U 6-917-108150 Samole No.