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HomeMy WebLinkAboutSWP272901(4) 1 1 1 1 i pEV 1 E� OF RE�ITJN LNG C, ��N 2 p 2000 1 1 1 1 1 1 NELSON-COUVRETTE & ASSOCIATES, INC. ' CONSULTING GEOTECHNICAL ENGINEERS, GEOLOGISTS AND ENVIRONMENTAL SCIENTISTS i 1 ' GEOTECHNICAL REPORT ' STONE LANE RENTON, WASHINGTON FOR WEST TIER DEVELOPMENT t NELSON-COUVRETTE & ASSOCIATES, INC. CONSULTING GEOTECHNICAL ENGINEERS, GEOLOGISTS AND ENVIRONMENTAL SCIENTISTS 17311-135th Avenue NE,A-500 Snohomish County(425)337-1669 Woodinville, WA 98072 Wenatchee/Chelan(509)784-2756 (425) 486-1669• Fax 481-2510 www.nelson-couvrette.com ' June 20, 2000 ' Mr. Peter Tiersma West Tier Development P.O. Box 1029 ' Woodinville, Washington 98072 ' Geotechnical Report Stone Lane Renton, Washington NCA File No. 288000 Dear Mr. Tiersma: This report summarizes our geotechnical evaluation of the proposed residential development known as Stone Lane, in Renton, Washington. INTRODUCTION The site is located on the west side of Queen Avenue NE, near its intersection with NE 5th Street, as ' shown on the Vicinity Map in Figure 1. You plan to develop the site with 14 single-family residences, roadways, a detention vault, and roof-drain infiltration galleries. You have requested a geotechnical ' report for the planned site improvements. We have been provided with a plan that is titled "Stone Lane Preliminary Plat Grading and Utilities Plan", dated May 2000,prepared by Touma Engineers. ' The existing residence, which was located along the center of the eastern edge of the approximately 1.5- acre site, has been demolished. The southeastern and central portions of the site are relatively clear of ' vegetation. The northern half and southwestern corners of the site are wooded. The demolished house likely had a septic tank and drain field that has been abandoned. We did not encounter the drain field or ' Geotechnical Report Stone Lane ' June 20,2000 NCA File No. 288000 Page 2 ' septic tank in our explorations. Plans show that the detention vault will be located in the southeastern corner of the property. The neighboring properties to the east, west, and south have been developed. ' The property to the north is wooded. ' You have informed us that you plan to infiltrate roof-drain runoff in infiltration trenches along the west side of all the lots. The exact design of the infiltration system is not known at this time. You have ' informed us that the bottom of the infiltration facilities will be approximately 3 feet below the existing ground surface elevation. SCOPE The purpose of our geotechnical study is to explore and characterize the subsurface conditions of the site and provide an infiltration rate for the proposed infiltration trenches. Specifically, for our scope of services we will: ' 1. Review soils and geologic maps for the site area. 2. Evaluate subsurface conditions with test pits excavated with a backhoe supplied by you. ' 3. Complete grain size analyses on three soil samples obtained in the field. ' 4. Perform three field infiltration tests in general accordance with the EPA falling head test method. Water supply to be provided by you. ' 5. Provide infiltration test results and recommended design infiltration rate. 6. Provide recommendations for site preparation, grading, and structural fill placement. 7. Provide recommendations for shallow foundation support. 8. Prepare a report,which documents or findings, conclusions, and recommendations. SITE CONDITIONS Surface The 1.5-acre site is rectangular in shape, with dimensions of 329 feet north to south by 200 feet east to ' west. The previously existing residence was located along the eastern edge of the property. A concrete slab was observed west of the old building location. ' NELSON-COUVRETTE & ASSOCIATES, INC. Geotechnical Report Stone Lane June 20,2000 NCA File No. 288000 Page 3 The southeastern portion of the site is open and covered with grass and blackberry vines. The southwestern and northern half of the site is heavily wooded with young to mature evergreen and ' deciduous trees and underbrush that consists of mainly salal, Indian plum, and other native vegetation. Geology ' We have reviewed the Geologic Map of the Renton Quadrangle, King County, Washington, by D. R. Mullineaux (U.S.G.S., 1965) for general geologic conditions in the project area. The geologic maps tindicate that the site is underlain by Vashon glacial till (Qgt) and Vashon recessional outwash specific to the Cedar River valley (Qpa). Glacial till is an unsorted mixture of sand, silt, clay and gravel that is deposited at the base of the glacier. Glacial till is commonly termed hardpan. The recessional outwash consists of stratified sand deposits with occasional gravel deposited by meltwater flowing from the ' receding continental glacier. Recessional outwash deposits are not glacially consolidated. Our explorations encountered a surficial layer of topsoil, glacial till underlain by advance outwash, and ' recessional outwash. Advance outwash is sand and gravel that was deposited by meltwater from the advancing glacier and subsequently overridden by the ice. Subsurface Conditions ' Subsurface conditions were explored at the site on June 7, 2000, by excavating six test pits using a rubber-tired, tractor-mounted backhoe. Test pit exploration depths ranged from 8.0 to 9.5 feet below the ' existing grade. The explorations were located in the field by a geologist from this office who also examined the soils and geologic conditions encountered and maintained logs of the test pits. The test pit explorations were located by measuring off of the existing site features and using the site plan provided. The approximate locations of the explorations 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 explorations are presented in Figures 4 and 5. We present a brief summary of the subsurface conditions in the following paragraphs. For a more ' detailed description of the site soils,the test pit logs should be reviewed. ' We encountered a 0.2- to 0.5-foot surficial layer of topsoil or forest duff in all our explorations, excluding Test Pit 3. Underlying the topsoil in Test Pit 1 and at the surface in Test Pit 3 we observed 0.8 ' NELSON-COUVRETTE & ASSOCIATES, INC. ' Geotechnical Report Stone Lane June 20, 2000 NCA File No. 288000 Page 4 ' to 1.8 feet of fill soil that consisted of loose to medium dense, grey-brown sand with gravel, roots, and organics. A 0.2-foot-thick layer of buried topsoil was observed under the fill in Test Pit 3. ' Underlying the topsoil, fill or buried topsoil in Test Pits 1 3 and 5 we y g p p encountered recessional outwash ' (Qpa) sand that consisted of medium dense to dense, fine to medium sand with verying amounts of coarse sand and gravel. The recessional outwash was observed to the maximum depth explored in these ' test pits. The uppermost part of the recessional outwash horizon was loose to medium dense and rust- stained to depths that range between 4.0 and 4.5 feet below the surface. ' We observed weathered advance outwash (Qva) in Test Pit 4 between 0.4 and 3.0 feet that consisted of ' loose to medium dense, slightly rust-stained, light grey sand with silt and trace roots. Unweathered advance outwash was observed from 3.0 feet to the maximum depth explored. The unweathered advance outwash consisted of grey sand with trace gravel. Underlying the forest duff in Test Pits 2 and 6,we observed 2.5 to 3.6 feet of weathered till that consisted of loose to medium dense, rust-stained sand with silt, gravel, and roots. Dense to very dense, grey silty sand to sand with silt and gravel was observed under the weathered till, which we interpreted to be unweathered till. The till extended to the full depth explored in Test Pit 6. In Test Pit 2, we observed 7.6 feet of till overlying 1 foot of advance outwash. We have shown approximate locations of the surficial geologic units on the site plan. These may be used for preliminary planning of the infiltration systems. However, this data is mostly for demonstrative purposes only and is based only on the exploration data points. The actual contacts between the units ' need to be determined during construction. ' Hydrology Groundwater seepage was not encountered in our explorations. We would expect slight groundwater ' seepage to accumulate on the unweathered till soils during the wetter months of the year. Rust staining of the soil was observed in all of the test pits at near-surface elevations. We attributed this staining to be due to the infiltration of surface water during the winter months and not due to a rise in the groundwater ' NELSON-COUVRETTE & ASSOCIATES, INC. ' Geotechnical Report Stone Lane ' June 20,2000 NCA File No. 288000 Page 5 ' elevation. Even though our explorations were during a wetter season, we anticipate that the groundwater level may rise during rainy periods. ' Stormwater Infiltration Rate ' We performed three infiltration tests in general accordance with the EPA falling head testing method within the proposed infiltration facility locations. These locations are shown as INF-1, 2, and 3 on the Site Plan in Figure 2. The infiltration rates for INF-1, 2, and 3 were 221 inches per hour, 226 inches per hour, and 38 inches per hour, respectively. These measured infiltration rates should be used for calculating the Design Infiltration Rate. The design infiltration rate, as defined by the 1998 King County Surface Water Design Manual, is equal to: ' Idesign—Imeasured x Ftesting x Fgeometry x Fplugging Where: ' Imeasured is the measured infiltration rate, Ftesting for the EPA testing method is 0.3, ' Fplugging is 0.9 for the soils designated sand and 0.8 for the soils designated loamy sand. Fgeometry term is a function of the size of the infiltration facility. The size of the infiltration facilities is unknown. In addition to the field infiltration rates,we conducted lab grain size analyses of the different soil types in three locations. The samples were collected at the proposed depth of the infiltration facilities in Test Pits 3,4, and 5, as shown on the Site Plan in Figure 2. The infiltration data is presented on Figures 6 through 8. The infiltration rates of these soils were also evaluated using the United States Department of Agriculture (U.S.D.A.) soil group classification (Figure III-3.1) as presented in the "Storm Water Management Manual for the Puget Sound Basin," (Ecology 1992). Based on our lab analyses of the grain sizes for these three samples, the soils in Test Pits 3 and 5 are classified as sand, while the soil in ' Test Pit 4 is a loamy sand. The manual provides an infiltration rate of 8.27 inches per hour for sand and 2.41 inches per hour for loamy sand. According the manual, these rates are the design infiltration rates. ' The grain size analyses for the soil in Test Pits 3 and 5 correspond to the soil type observed at INF-1 and INF-2,while the soils in Test Pit 4 corresponds to the soils type observed at INF-3. It is our opinion that the permeability numbers provided in the Ecology manual are conservative. ' NELSON-CO UVRETTE & ASSOCIATES, INC. ' Geotechnical Report Stone Lane June 20, 2000 NCA File No. 288000 Page 6 CONCLUSIONS AND RECOMMENDATIONS General ' The underlying medium dense or better native weathered and unweathered outwash and till soils are capable of supporting the planned structure and pavements. It is our opinion that the planned structure ' may be supported on conventional shallow spread footings. Foundations should extend through any topsoil, fill, or loose surface soils and bear on the underlying medium dense or better native soils or on ' structural fill extending to these soils. We observed advance outwash, recessional outwash, and glacial till at the specified infiltration depth of 3 feet for the proposed roof drain infiltration systems. The outwash sand and gravel soils are suitable for ' infiltration of the root drain runoff. The dense, silty till soils are relatively impermeable and we expect infiltration would be extremely slow. In our opinion the till soils are not suitable for infiltration ' purposes. Given the limited scope of our explorations, we would expect till soils in the infiltration areas of Lots 7, 13, and 14. The infiltration areas of additional lots may also be affected by impermeable till ' soils. The weathered and unweathered outwash soils likely to be exposed during construction vary in moisture sensitivity and the siltier till could disturb easily when wet. Construction during the drier summer months would decrease the chance for disturbing the weathered native soils by construction activities. If ' construction takes place during the wet season, additional expenses and delays may be expected due to the wet conditions. Additional expenses could include the repair of areas disturbed by construction activities and increase erosion control measures. ' Erosion Control The on-site soils have a slight to moderate erosion potential when disturbed; depending on how the site is 1 graded and 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. Cut slopes may be protected from erosion by diverting surface water away from the top of slope and covering cut slopes with plastic ' sheeting. Silt fences or straw bales should be erected to prevent muddy water from leaving the site. Disturbed areas should be revegetated or mulched at the end of construction. The vegetation should be ' NELSON-COUVRETTE & ASSOCIATES, INC. Geotechnical Report Stone Lane ' June 20, 2000 NCA File No. 288000 Page 7 maintained until it is well established. The erosion potential of areas not stripped of vegetation should be minimal. ' Site Preparation and Grading ' The first step of site preparation should be to strip the topsoil or disturbed soils to reveal medium dense or better native soils in pavement, roadways, and building areas. The stripped material should be i removed from the site or stockpiled for later use as landscaping fill. Subgrades that are at grade or are to receive fill should be thoroughly compacted to a firm, non-yielding condition. The performance of the ' subgrade should be evaluated by NCA at the time of construction. Areas observed to pump or weave should be repaired prior to placing structural fill,pavement, or structures. ' The on-site weathered soils and glacial till are considered moderately to highly moisture sensitive and may be difficult to work with in wet weather. We expect these soils may be difficult to compact to structural fill specifications in wet weather or wet conditions. We recommend that earthwork be conducted during the drier summer months. Additional expenses of wet weather or winter construction ' could include extra excavation and export, and use of imported fill or rock spalls. Disturbance to the prepared subgrade may be minimized by placing a blanket of rock spalls or imported sand and gravel in traffic and roadway areas. This can be evaluated at the time of construction. Structural Fill General: We do not expect a significant amount of fill to be placed on the site. 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. 1 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 fill should contain no more than about 5 percent fines (soil finer than a U.S. No. 200 sieve),based on the fraction passing the U.S. 3-inch sieve. ' NELSON-COUVRETTE & ASSOCIATES, INC. Geotechnical Report Stone Lane ' June 20, 2000 NCA File No. 288000 Page 8 ' The native recessional outwash soils vary in moisture sensitivity,based on the fines content. Most of the native soils would be suitable for structural fill. The re-use of the existing on-site fill is dependent upon ' the amount of organics or debris in the fill. The appropriateness of the on-site soils for fill could be determined at the time of construction. Fill Placement: Following subgrade preparation, placement of the structural fill may proceed. All backfilling should be accomplished in 6- to 8-inch-thick uniform lifts. Each lift should be spread evenly and be thoroughly compacted prior to placement of subsequent lifts. All structural fill underlying building areas and within 2 feet of pavement subgrade should be compacted to a minimum of 95 percent of its maximum dry density. Maximum dry density, in this report, refers to that density as determined by ' the ASTM D 1557 compaction test procedure. Fills more than 2 feet beneath sidewalk and pavement subgrade should be compacted to 90 percent of their maximum dry density. The moisture content of the soils to be compacted should be within about 2 percent of optimum so that a readily compactable condition exists. It may be necessary to overexcavate 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. ' Foundations It is our opinion that the planned structures may be founded on shallow, conventional foundations. ' Conventional foundations should extend a minimum of 1 foot into the undisturbed, medium dense or better native soils. Footings should extend a minimum of 18 inches below the finished ground surface and interior column footings extend a minimum of 12 inches. Minimum foundation widths of 16 and 20 inches should be used for continuous and isolated 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 and founded on undisturbed native soil,we recommend an ' allowable design bearing pressure of 2,000 pounds per square foot (psf) be used for the footing design. Higher bearing pressures could be used based on a review of specific plans. A one-third increase in the NELSON-COUVRETTE & ASSOCIATES, INC. Geotechnical Report Stone Lane t June 20,2000 NCA File No. 288000 Page 8 ' The native recessional outwash soils vary in moisture sensitivity, based on the fines content. Most of the native soils would be suitable for structural fill. The re-use of the existing on-site fill is dependent upon the amount of organics or debris in the fill. The appropriateness of the on-site soils for fill could be determined at the time of construction. Fill Placement: Following subgrade preparation, placement of the structural fill may proceed. All backfilling should be accomplished in 6-to 8-inch-thick uniform lifts. Each lift should be spread evenly and be thoroughly compacted prior to placement of subsequent lifts. All structural fill underlying ' building areas and within 2 feet of pavement subgrade should be compacted to a minimum of 95 percent of its maximum dry density. Maximum dry density, in this report, refers to that density as determined by ' the ASTM D 1557 compaction test procedure. Fills more than 2 feet beneath sidewalk and pavement subgrade should be compacted to 90 percent of their maximum dry density. The moisture content of the ' soils to be compacted should be within about 2 percent of optimum so that a readily compactable condition exists. It may be necessary to overexcavate 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. ' Foundations It is our opinion that the planned structures may be founded on shallow, conventional foundations. ' Conventional foundations should extend a minimum of 1 foot into the undisturbed, medium dense or better native soils. Footings should extend a minimum of 18 inches below the finished ground surface and interior column tfootings extend a minimum of 12 inches. Minimum foundation widths of 16 and 20 inches should be used for continuous and isolated 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 and founded on undisturbednative i at ve soil,we recommend an allowable design bearing pressure of 2,000 pounds per square foot (psf) be used for the footing design. Higher bearing pressures could be used based on a review of specific plans. A one-third increase in the NELSON-COUVRETTE & ASSOCIATES, INC. ' Geotechnical Report Stone Lane ' June 20, 2000 NCA File No. 288000 Page 9 ' above allowable bearing pressure may be used when considering short-term transitory wind or seismic loads. Although structural loading information was not available at the time of this study, based on our ' experience with structures supported on similar soil conditions and for the above allowable soil bearing pressures, we estimate that total post-construction settlement should be 1 inch or less and that the differential settlement should be 1/2 inch in 20 feet or less. Slabs-on-Grade ' The subgrade for slabs-on-grade should be prepared as outlined in our Site Preparation and Grading subsection. Soils that are observed to weave during compaction should be overexcavated and replaced ' with structural fill. Where moisture control is important, we recommend that at least 6 inches of free- draining material be placed under slabs-on-grade to act as a capillary break. The capillary break material ' should be separated from slabs by a vapor barrier, such as 6-mil plastic sheeting. An additional 2-inch- thick, damp sand blanket should be used to cover the vapor barrier to protect the membrane and to aid in ' curing the concrete. This will also help prevent cement paste bleeding down into the capillary break through joints or tears in the vapor barrier. The capillary break material should be connected to the footing drains to provide positive drainage. Pavements ' Roadway subgrade preparation and structural filling where required, should be completed as recommended in the Site Preparation and Grading and Structural Fill subsections of this report. The subgrade should be proofrolled with a heavy, rubber-tired piece of equipment to identify soft or yielding areas that require repair. Areas that are observed to pump or weave should be overexcavated and replaced with structural fill. We should be retained to observe the proofrolling and recommend repairs prior to placement of the asphalt or hard surfaces. For pavement areas prepared as above, we ' recommend that a conventional pavement section be used. ' Detention Vault Footings should be placed on the medium dense or better, unweathered glacial soils or structural fill ' extending to these soils. We recommend that an allowable design bearing pressure of not more than 3,000 psf be used for footings at least 2 feet wide. Higher bearing pressures may be appropriate based on ' a specific design. We are available to review specific design and loading conditions at your request. NELSON COUVRETTE &ASSOCIATES, INC. ' Geotechnical Report Stone Lane ' June 20, 2000 NCA File No. 288000 Page 10 ' 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 an"at-rest" condition. 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 60 pcf, respectively, may be used for design for a level ' backslope. These values assume that the on-site soils or granular import soils are used for backfill, are compacted to at least 90 percent of maximum dry density from ASTM D 1557, and that the wall backfill ' is drained. The preceding values do not include the effects of surcharges, such as foundation loads, traffic or other surface loads. Surcharge effects should be considered where appropriate. Though ' groundwater was not observed in our explorations, we recommend that buoyant loads be considered in the structural design of the vault. The above lateral pressures may be resisted by friction at the base of the structure and passive resistance ' against subsurface walls and the foundation. A coefficient of friction of 0.4 may be used to determine the base friction in the glacial soils. An equivalent fluid density of 250 pcf should be used for passive resistance design. These recommended values incorporate safety factors of 1.5 and 2.0 applied to the estimated ultimate values for frictional and passive resistance, respectively. To achieve this value of passive resistance, the foundations should be poured "neat" against the native dense soils, or compacted fill should be used as backfill against the front of the footing, and the soil in front of the wall should ' extend a horizontal distance at least equal to three times the foundation depth. We recommend that the upper 1 foot of soil be neglected when determining the passive resistance. ' Drainage Surface: We recommend that runoff from impervious surfaces, such as roofs and paved areas, be ' collected and routed to an appropriate storm water discharge system. The roof drains should be tightlined separate of the footing drains, until the tightline is a minimum of 1 foot vertically down ' gradient from the footing drains. ' Final site grades should allow for drainage away from the buildings. We suggest that the finished ground 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. NELSON-COUVRETTE & ASSOCIATES, INC. tGeotechnical Report Stone Lane ' June 20, 2000 NCA File No. 288000 Page 11 ' Infiltration System: The infiltration systems should work satisfactorily for the roof drains, provided they are properly sized. The systems should located such that they are in the outwash areas. This means ' that lots with till near the ground surface should have the roof drains routed to locations where the outwash is near surface. The geologic conditions shown on the Site Plan should give preliminary data as ' to where we expect till and outwash will exist. This will have to be verified in the field. ' Subsurface Drainage: We did not encountered groundwater seepage in our explorations. We anticipate that perched groundwater may accumulate on the surface of the more impermeable unweathered till soils during the wetter months of the year. It is good practice to use footing drain systems around the perimeter of the planned buildings. Footing drains should be installed at least 1 foot below planned finished floor slab or crawl space elevation. The ' 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. 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. USE OF THIS REPORT ' We have prepared this report for Mr. Peter Tiersma and his agents, for use in planning and design of this project. The data and report should be provided to contractors for their 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. We recommend that we be retained to provide monitoring serviced during construction. As part of our services we would verify that conditions encountered in the field are consistent with those found in our ' NELSON-COUVRETTE & ASSOCIATES, INC. tGeotechnical Report Stone Lane ' June 20, 2000 NCA File No. 288000 Page 12 ' explorations. Specifically, we would evaluate the infiltration areas as they are excavated. We would provide recommendations for adjustments in the field as necessary,base on conditions observed. Within the limitations of scope, schedule, and budget for our services, we have striven 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. It has been a pleasure to provide service to you on this project. If you have any questions or require further information,please call. ' Sincerely, ' NELSON-COUVRETTE&ASSOCIATES, INC. /46; ' Kenneth J. Reid ' Senior Staff Geologist ' ytis�wA�tr i v i 10/2,6/oo x ONAL ECG ' E F-,I ES 1-7/ O 7- Charles P. Couvrette, PE Principal Engineer KJR:CPC:nt Eight Copies Submitted ' Eight Figures ' NELSON-CO UVRETTE & ASSOCIATES, INC. t Vicinity Map N t D E F G 8TH 7TH . E� _ z >C `r 6TH �,E uric Project TH x' SiteTH K ' 3 � BRby � � y 210 a E E EH , 1f i a I L-- t: j cb E cat 3 1 ©1 995 Thomas Bros. Maps Not to scale t ' NELSON-COUVRETTE & ASSOCIATES, INC. Stone Lane CONSULTING GEOTECHNICAL ENGINEERS,GEOLOGISTS AND ENVIRONMENTAL SCIENTISTS FILE NO. FIGURE 288000 1 ' Company\ncadrafting2000\coreldraw\vicinity\2880vic.cdr:trc,6/12/00 Site Plan ' POR 110N OF THE SW 114 OF THE SE 114 SEC77ON 9, TOWNSHIP 23 NORM, RANGE 5 EAST, W.M. FIILL TOP CITY OF R TON, STATE OF WASHINGTON � PLA T < ` , SINGLE. FAWL Y _ 88. W �00. 4 — 02- T -'83 .. 3,915.9 N L �,o � DTP-6 \ - — y , s ,3,915.9 sq.ft.\ NW1111k V INF-3 L N8897S`w-70 ; 1 � P1915.9� ft. � gru TP-4_ ' o IN F-2 W— J ` _ N8839_'18*W_ - — '� _ 93.53, Z ' O 3,915.9 sq.�t, �� N 4 +. Wlli ,c LEGEND ti I L —w88s9'rrW— J� TP-3� + li, --NBa�s ' ' F — _e702L — i Glacial Till �o 12 , 3,915.0 sq.fr. 8 r BE`""" Advance Outwash R OVED4'215. s 71.- L Recessional Outwash o L N88�s7a'w-'�r-� I N88S� LB"w R' TP-1 I 93. Number and Approximate -T'— oRruE — 1 Location of Test Pit 1 N � �_ J• / 4,220.21sq.fr. INF-1 INF- ,: -91& �. , Number and Approximate Location of Infiltration Test 5,515.1 sq..t. ( ' TP 1 The surficial mapping showing the locations of the boundaries between geologic units, is F a rough interpretation between explorations. i ME 939 01' They are for demonstrative purposes only N89 01'32"W 200.99' ; and should not be construed as accurate. 0 50 100 Reference: Site plan based on "Stone Lane Preliminary Plat, Grading ' & Utilities Plan," by Touma Engineers, dated May, 2000. Scale 1" = 50' ' NELSON-COUVRETTE &ASSOCIATES, INC. Stone Lane CONSULTING GEOTECHNICAL ENGINEERS,GEOLOGISTS AND ENVIRONMENTAL SCIENTISTS FILE NO. FIGURE 288000 2 Company\n cad rafting2000\coreldraw\siteplan\2880sp.cdr:trc/krt,6/15/00 UNIFIED SOIL CLASSIFICATION SYSTEM MAJOR DIVISIONS GROUP GROUP NAME SYMBOL COARSE - GRAVEL CLEAN GRAVEL GW WELL-GRADED GRAVEL,FINE TO COARSE GRAVEL ' GRAINED MORE THAN 50%OF GP POORLY-GRADED GRAVEL ' COARSE FRACTION SOILS RETAINED ON NO.4 GRAVEL GM SILTY GRAVEL SIEVE WITH FINES ' GC CLAYEY GRAVEL MORE THAN 50% RETAINED ON SAND CLEAN SAND Sys/ WELL-GRADED SAND,FINE TO COARSE SAND NO.200 SIEVE ' SP POORLY-GRADED SAND MORE THAN 50%OF COARSE FRACTION SAND ' PASSES NO.4 SIEVE WITH FINES SM SILTY SAND SC CLAYEY SAND ' FINE - SILT AND CLAY INORGANIC ML SILT GRAINED LIQUID LIMIT CL CLAY LESS THAN 50% SOILS ORGANIC OL ORGANIC SILT,ORGANIC CLAY MORE THAN 50% SILT AND CLAY PASSES NO.200 SIEVE INORGANIC MH SILT OF HIGH PLASTICITY,ELASTIC SILT ' LIQUID LIMIT CH CLAY OF HIGH PLASTICITY,FAT CLAY 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. Moist- Damp, but no visible water 2) Soil classification using laboratory ' 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 on below water table ' interpretation of blowcount data, visual appearance of soils, and/or test data. NEELSON-COUVRETTE&ASSOCIATES, INC. UNIFIED SOIL CLASSIFICATION SYSTEM CONSULTING GEOTECHNICAL ENGINEERS,GEOLOGISTS AND ENVIRONMENTAL SCIENTISTS FIGURE 3 Company\drafting2000\coreldraw\samples\soilclas.cdr LOG OF EXPLORATION DEPTH USC SOIL DESCRIPTION ' TEST PIT ONE 0.0-0.2 TOPSOIL 0.2-2.0 SP GRAY, FINE SAND WITH TRACE GRAVEL WITH ROOTS AND ORGANICS (LOOSE TO ' MEDIUM DENSE, MOIST)(FILL) 2.0-4.0 SP RUST-STAINED FINE SAND WITH TRACE SILT AND ROOTS (LOOSE TO MEDIUM DENSE, MOIST)(WEATHERED RECESSIONAL OUTWASH) ' 4.0-8.0 SP GREY FINE TO MEDIUM SAND WITH TRACE GRAVEL (DENSE, MOIST) (RECESSIONAL OUTWASH) SAMPLES WERE COLLECTED AT 1.5,3.5,AND 8.0 FEET ' GROUND WATER SEEPAGE WAS NOT ENCOUNTERED SLIGHT TEST PIT CAVING WAS ENCOUNTERED BETWEEN 6 AND 8 FEET TEST PIT WAS COMPLETED AT 8.0 FEET ON 06/07/00 TEST PIT TWO 0.0-0.4 FOREST DUFF ' 0A-1.0 SP-SM RUST-STAINED FINE SAND WITH SILT AND ROOTS (LOOSE, MOIST) (WEATHERED TILL) 1.0-4.0 SM GREY SLIGHTLY RUST-MOTTLED SILTY FINE SAND WITH GRAVEL(MEDIUM DENSE, MOIST)(WEATHERED TILL) ' 4.0-8.0 SM GREY SILTY FINE SAND WITH GRAVEL(DENSE, MOIST)(TILL) 8.0-9.0 SP GREY-BROWN FINE TO MEDIUM SAND(DENSE, MOIST)(ADVANCE OUTWASH) ' SAMPLES WERE COLLECTED AT 1.5,6.0,AND 8.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 9.0 FEET ON 06/07/00 ' TEST PIT THREE 0.0-0.8 SP GREY-BROWN FINE TO MEDIUM SAND WITH GRAVEL AND ORGANICS (LOOSE, ' MOIST)(FILL) 0.8-1.0 SM BURIED TOPSOIL(LOOSE,MOIST) 1.0-4.5 SP-SM RUST-STAINED FINE TO MEDIUM SAND WITH SILT AND ROOTS (MEDIUM DENSE, MOIST)(WEATHERED RECESSIONAL OUTWASH) 4.5-6.0 SW GREY FINE TO COARSE SAND WITH GRAVEL (DENSE, MOIST) (RECESSIONAL OUTWASH) 6.0-9.0 SP GREY FINE TO MEDIUM SAND(DENSE, MOIST)(RECESSIONAL OUTWASH) SAMPLES WERE COLLECTED AT 5.0 AND 8.0 FEET ' GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 9.0 FEET ON 06/07/00 TEST PIT FOUR ' 0.0-0.4 FOREST DUFF 0.4-1.5 SP SLIGHTLY RUST-STAINED LIGHT GREY FINE SAND WITH TRACE ROOTS(LOOSE TO ' MEDIUM DENSE, MOIST)(WEATHERED ADVANCE OUTWASH) 1.5-3.0 SP RUST-STAINED FINE SAND WITH TRACE SILT AND ROOTS (LOOSE TO MEDIUM DENSE,MOIST)(WEATHERED ADVANCE OUTWASH) ' kjr NELSON-COUVRETTE&ASSOCIATES, INC. FILE NO 288000 ' FIGURE 4 ' LOG OF EXPLORATION ' DEPTH USC SOIL DESCRIPTION ' 3.0-8.5 SP GREY FINE TO MEDIUM SAND WITH TRACE SILT AND GRAVEL (DENSE, MOIST) (ADVANCE OUTWASH) SAMPLES WERE COLLECTED AT 2.0 AND 7.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 8.5 FEET ON 06/07/00 TEST PIT FIVE 0.0-0.4 FOREST DUFF 0.4-4.0 SP-SM RUST-STAINED FINE TO MEDIUM SAND WITH SILT AND ROOTS (LOOSE TO MEDIUM DENSE)(WEATHERED RECESSIONAL OUTWASH) 4.0-6.0 SP GREY FINE TO MEDIUM SAND WITH GRAVEL (DENSE, MOIST) (RECESSIONAL OUTWASH) ' 6.0-7.0 SW GREY FINE TO COARSE SAND WITH GRAVEL (DENSE, MOIST) (RECESSIONAL OUTWASH) 7.0-8.0 GREY FINE TO MEDIUM SAND WITH TRACE GREVEL (DENSE, MOIST) ' (RECESSIONAL OUTWASH) SAMPLES WERE COLLECTED AT 4.5 AND 6.5 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED ' TEST PIT WAS COMPLETED AT 8.0 FEET ON 06/07/00 TEST PIT SIX ' 0.0-0.5 FOREST DUFF 0.5-2.5 SP-SM RUST-STAINED FINE TO MEDIUM SAND WITH SILT AND ROOTS (LOOSE TO MEDIUM DENSE)(WEATHERED TILL) ' 2.5-9.5 SP-SM GREY FINE TO MEDIUM SAND WITH SILT AND GRAVEL(VERY DENSE, MOIST)(TILL) SAMPLES WERE COLLECTED AT 2.6 AND 6.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED ' TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 9.5 FEET ON 06/07/00 ' kjr NELSON-COUVRETTE&ASSOCIATES, INC. FILE NO 288000 ' FIGURE 5 U.S. STANDARD SIEVE SIZE fq 100 �� m OmynzOzZ otiGm=�� n0 90 $O 70 w60 z 50 G) LLJI Z msn LL 40n� m W c, o Q 30 o d 20� IL ,i,,,IIIII CZ I 0 102o -� { T7 IIIIIII�i II1iIIII1 IIIIII1I ftp d T x m 1000 100 10 1.0 0.1 0.01 0.001 z N ° GRAIN SIZE IN MILLIMETERS 0 o N ci 00 9 00 GRAVEL SAND m o COBBLES SILT OR CLAY n O (/) COARSE FINE COARSE MEDIUM FINE O EXPLORATION SAMPLE � 17— _ v SYMBOL NUMBER DEPTH SOIL DESCRIPTION W c T <' 0 X • Test Pit #3 5 feet Grey fine to coarse sand with gravel m rn 0') 0 0 U.S. STANDARD SIEVE SIZE m3�� �� 5\�`\�' 3\�\�' Cep 1° �p CepC)p.,lop \p C�p�°° - - V� 100 o ^? 90 r O 1 I I I 80 I I I m y 70 WIL O ? QO 60 o<_ m C, Gzj w 50 i z m O Z m 40 n Z Co ,n m ui 11l O U 30 I1.1 J, � 20 i I I ' I � ' I 'I, O 10 I I I I I II � O n v m 1000 100 10 1.0 0.1 0.01 0.001 s Z N o GRAIN SIZE IN MILLIMETERS 0 o N 00 ° Oo GRAVEL SAND CD COBBLES SILT OR CLAY n O (n COARSE FINE COARSE MEDIUM I FINE O p m EXPLORATION SAMPLE -- v SYMBOL NUMBER DEPTH SOIL DESCRIPTION O00 T. T < Z � • Test Pit #4 7 feet Grey fine to medium sand with trace silt and gravel m N O O O O U.S. STANDARD SIEVE SIZE 1p.`° �p?° N �p. ° N°�p \ `O°�p. p.`�°gyp W 100 TT o ? 90 ! I ! 80 I I I I I m m 4, '., I , z Z m 70 U-1 so o QO } I I I I 1 I I m 50 o W Z W - Z � n u- 40 r �I z m m w m O � U 30 `/) `o a 20 I i O N 104, I I I I 1 I � I 1 n T 0 tv C m 1000 100 10 1.0 0.1 0.01 0.001 Z o GRAIN SIZE IN MILLIMETERS 0 0 o N o 00 GRAVEL SAND m 00 W COBBLES SILT OR CLAY a O COARSE FINE COARSE MEDIUM I FINE f O :3 n CD EXPLORATION SAMPLE co CD SYMBOL NUMBER DEPTH SOIL DESCRIPTION co T O G 0 m • Test Pit #5 4.5 feet Grey fine to medium sand with gravel m 00 a 0