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Geotechnical Report.pdfJune 26, 2015 Revised August 17, 2015 ES -3960.01 Highpoint Investments, LLC 14915 — 102nd Avenue Northeast Bothell, Washington 98011 Attention: Mr. Rob Purser Subject: Geotechnical Consulting Services Proposed Cheeks Residential Short Plat 22920 —102nd Place West Edmonds, Washington Reference: Conceptual Site Plan Axis Survey & Mapping Topographic Survey, dated May 29, 2015 Washington State Department of Ecology Stormwater Management in Western Washington Publication No. 05-10-31, dated February 2005 Dear Mr. Purser: Earth Solutions NWrrC Earth Solutions NW I_I-c • Geotechnical Engineering • Construction Monitoring • Environmental Sciences In accordance with your request, Earth Solutions NW, LLC (ESNW) has prepared this revised letter summarizing our geotechnical consulting services performed for the subject project. A representative of ESNW visited the site on June 15, 2015 to conduct explorations at accessible locations of the parcel. 0 0 I ,w r The current site layout proposes to subdivide the subject property into four residential lots. A new access road will be constructed to provide entry and egress for the new lots. This letter covers the Snohomish County Tax Parcel No. (TPN) 006107-001-005-00. The approximate location of the subject parcel is illustrated on Plate 1. We understand the feasibility of infiltration for new impervious surfaces is being investigated. The process of determining appropriate flow control is provided in Chapter 3 of the referenced 2005 Stormwater Management Manual for Western Washington (SMMWW). 1805 - 136th Place N.E., Suite 201 0 Bellevue, WA 98005 0 (425) 449-4704 • FAX (425) 449-4711 Highpoint Investments, LLC June 26, 2015 Revised August 17, 2015 Subsurface Conditions ES -3960.01 Page 2 Subsurface conditions were evaluated by observing, logging, and sampling four test pits, excavated at accessible locations of the site, using a trackhoe and operator retained by ESNW on June 15, 2015. Representative soil samples were collected for USDA textural classification. The approximate test locations are depicted in the shaded region on Plate 2. In general, the site is underlain by topsoil and weathered native soils consisting primarily of loose to medium dense silty sand (Unified Soil Classification System: SM) extending to maximum depths of approximately six feet. Underlying the weathered soil zone, relatively clean sand and gravel (USCS: SP, SP -SM, and GW) were encountered extending to the maximum exploration depth of 10 feet below existing grades. Local geologic mapping identifies Vashon till (Qvt) as the primary geologic unit underlying the subject site. Vashon advance outwash (Qva) is mapped to underlie areas encompassing the subject site. Based on our field observations, site soils encountered during construction will be consistent primarily with Vashon advance outwash rather than Vashon till. In general, Vashon advance outwash is comprised primarily of clean pebbly sand; significant gravel content is common within the upper portions of the geologic unit. Groundwater Groundwater was not observed at the test pit locations at the time of our exploration (June 15, 2015). Groundwater seepage rates and elevations fluctuate depending on many factors, including precipitation duration and intensity, the time of year, and soil conditions. In general, groundwater flow rates are higher during the wetter, winter months. Infiltration Evaluation Our infiltration evaluation consisted of classifying representative soils by textural class in accordance with the USDA Textural Triangle, as outlined in the referenced SMMWW. Using USDA textural classification guidelines, the site soils consist primarily of extremely gravOly coarse sand and isolated layers of gravelly'loamy coarse sand, with fines contents ranging from about 1 to 5 percent. It should be noted the soil tested at test pit location TP -5, at a depth of about six feet, contained approximately 0.6 percent fines and maintained the identical USDA soil classification of "gravelly coarse sand". In general, site soils should be considered free draining, as in-situ fines contents are less than 5 percent. A confining layer was not encountered at the test pit locations. Either drywells or infiltration trenches are suitable for this project. In any event, a minimum vertical separation of three feet between the bottom of the facility and the seasonal high groundwater table must be maintained. ESNW should be consulted to review final infiltration designs so as to confirm adequate separation distance has been incorporated into the plans and to provide additional recommendations where necessary. Section 3.1.1 of the referenced SMMWW provides design guidelines for downspout infiltration. Earth Solutions Nw, LLC Highpoint Investments, LLC June 26, 2015 Revised August 17, 2015 Design Considerations ES -3960.01 Page 3 Infiltration trenches should be designed using a minimum trench length of 20 feet per 1,000 square feet of impervious surface served. Figures 3.2 and 3.3 of the referenced SMMWW provide construction guidelines for infiltration trenches. Drywells may be used where coarse sand is present. For this site, drywells may be designed using a minimum gravel volume of 60 cubic feet per 1,000 square feet of impervious surface served. Figure 3.4 of the referenced SMMWW provides construction guidelines for drywells. As indicated on Table 3.7 of the referenced SMMWW, a long-term infiltration rate of 2.0 inches per hour may be assumed for preliminary design of infiltration facilities extending into the native coarse sands. We reviewed Chapter 23.80 of the Edmonds Municipal Code (EMC) to determine the presence of geologically hazardous areas on site. The majority of the lot contains gentle slope gradients of approximately 10 percent or less. Slope gradients increase in the western areas. As indicated on the referenced topographic survey, slope gradients in the western approximately one-quarter of the lot range up to about 40 percent and are a maximum of about ten feet in height. These areas appear to be natural relic drainage features. EMC Section 23.80.020 provides classification for erosion and landslide hazard areas. The western approximately one-quarter of the site would be considered a moderate erosion hazard area as defined in the EMC. The steeper slopes on this site are largely isolated and are ten feet or fewer in total heights. Based on the referenced topographic survey, it appears that the slope gradients generally decrease off site to the west. In this respect, the slopes on the subject site do not meet the criteria for landslide hazard area designation. Additionally, the site soil and groundwater conditions are generally consistent with a low seismic hazard due primarily to the relative soil density, soil gradation, and absence of a uniformly established groundwater table. In our opinion, standard Best Management Practices (BMPs) and setbacks may be applied to the site layouts for the subject parcel. With respect to downspout infiltration, in our opinion, given the isolated nature of the steeper,sloped areas and the depth of sand and gravel across the site, construction of infiltration trenches for the westernmost lot is feasible and will not increase the potential for instability on the site or adjacent properties. Foundations Based on the conditions encountered at the test pit locations, construction of the new residential structures and associated improvements at the subject site is feasible from a geotechnical standpoint. Where loose or unsuitable soil conditions are encountered at foundation subgrade elevations, compaction of the soils to the specifications of structural fill, or overexcavation and replacement with structural fill may be necessary. Overexcavations may be required at some locations depending on the conditions encountered during construction; however, the ultimate extent of overexcavation activities should be determined by ESNW during construction. Earth Solutions NW, LLC Highpoint Investments, LLC ES -3960.01 June 26, 2015 Page 4 Revised August 17, 2015 The following parameters may be used for foundation design: Allowable soil bearing capacity 2,500 psf • Passive earth pressure 300 pcf Coefficient of friction 0.40 The passive resistance value provided above assumes the foundations will be backfilled with structural fill. A factor -of -safety of 1.5 has been applied to the passive resistance and friction values provided in this section. For short-term wind and seismic loading, a one-third increase in the allowable soil bearing capacity may be assumed. With structural loading as expected, total settlement in the range of one inch, as well as differential settlement of approximately one-half inch, is anticipated. The majority of the settlements should occur during construction, as dead loads are applied. Structural Fill Structural fill is defined as compacted soil in foundation, slab -on -grade, and roadway areas. Fills placed to construct permanent slopes and throughout retaining wall and utility trench backfill areas are also considered structural fill. Soils placed in structural areas should be placed in maximum 12 -inch loose lifts and be compacted to a relative compaction of 95 percent, based on the laboratory maximum dry density as determined by the Modified Proctor Method (ASTM D1557). Fill should be placed on a level surface, particularly in the western portions of the site where slope gradients are marginally higher. We recommend placing fill on a benched surface in areas where slope gradients are in excess of about 20 percent. ESNW should be consulted during early grading activities to identify areas where benched fills are appropriate and to provide additional recommendations as necessary. Temporary Excavations and Permanent Slopes The Federal Occupation Safety and Health Administration (OSHA) and the Washington Industrial Safety and Health Act (WISHA) provide soil classification in terms of temporary slope inclinations. Soils encountered at the test pit locations are classified as Type B by OSHA and WISHA. Temporary slopes over four feet in height in Type B soils should be sloped no steeper than 1 H:1 V (Horizontal:Vertical). ESNW should observe temporary and permanent slopes to confirm the inclinations are appropriate for the exposed soils and to provide additional grading recommendations as necessary. If temporary slopes cannot be constructed in accordance with OSHA and WISHA guidelines, temporary shoring may be necessary. Permanent slopes should maintain a gradient of 2HAV, or flatter, and should be planted with an appropriate species of vegetation to enhance stability and to minimize erosion. Earth Solutions NW, LLC Highpoint Investments, LLC June 26, 2015 Revised August 17, 2015 Slab -on -Grade Floors ES -3960.01 Page 5 The slab -on -grade floors should be supported on a suitable capillary break material underlain by undisturbed, competent native soil or a compacted structural fill subgrade. Structural fill in slab -on -grade areas should be compacted to a minimum relative compaction of 95 percent throughout the upper one foot of subgrade. Unstable or yielding areas of the subgrade should be recompacted, or overexcavated and replaced with suitable structural fill, prior to construction of the slab. Slab -on -grade areas should be provided with a minimum four -inch capillary break. Capillary break soils should consist of a granular, free -draining sand and gravel soil that contains less than 5 percent fines (percent passing the Number 200 sieve, based on the minus three -quarter - inch fraction). In general, to help facilitate grading of the slab subgrade, the maximum aggregate size of the capillary break material should generally be one -and -one-quarter inch. In areas where slab moisture is undesirable, installation of a vapor barrier placed below the slab should be considered. If a vapor barrier will be utilized, it should consist of a material specifically designed for that use and should be installed in accordance with the specifications of the manufacturer. If retaining walls will be used on this project, they should be designed to resist earth pressures and any applicable surcharge loads. For design, the following parameters may be assumed for retaining wall design: 0 Active earth pressure (yielding condition) At -rest earth pressure (restrained condition) * Traffic surcharge (passenger vehicles) o Passive earth pressure Coefficient of friction Seismic surcharge 35 pcf (equivalent fluid) 55 pcf 70 psf (rectangular distribution) 300 pcf (equivalent fluid) 0.40 6H (where H = retained height) Additional surcharge loading from foundations, sloped backfill, or other loading should be included in the retaining wall design. Drainage should be provided behind retaining walls such that hydrostatic pressures do not develop. If drainage is not provided, hydrostatic pressures should be included in the wall design. ESNW should review the retaining wall designs to verify that appropriate earth pressure values have been incorporated and to provide additional recommendations as necessary. Earth Solutions NW, LLC Highpoint Investments, LLC June 26, 2015 Revised August 17, 2015 ES -3960.01 Page 6 Retaining walls should be backfilled with free -draining material that extends along the height of the walls and a distance of at least 18 inches behind the wall. The upper one foot of wall backfill can consist of a less permeable soil, if desired. A perforated drain pipe should be placed along the base of retaining walls and tightlined to an approved discharge location. -m—m—N—M m.. The 2012 International Building Code specifies several soil profiles that are used as a basis for seismic design of structures. Based on the soil conditions observed at the test sites, Site Class D should be used for design. In our opinion, the site has a low susceptibility to liquefaction based on the absence of a uniformly established groundwater table and the relative density of the site soils observed at the test pit locations. Temporary measures to control surface water runoff during construction would likely involve interceptor trenches and sumps. Based on the soil and groundwater conditions observed at the test sites, active dewatering of utility excavations will likely not be necessary. In our opinion, footing drains can be omitted if relatively clean sands and/or gravels are encountered at the building subgrade elevations. ESNW should observe these areas to determine if footing drains will be necessary. If footing drains are recommended, they should be installed along the building perimeters. Exterior grades should be sloped away from buildings at a gradient of at least 2 percent for a minimum distance of 10 feet. We trust this letter meets your current needs. Should you have questions, or if additional information is required, please call. Sincerely, EARTH SOLUTIONS NW, LLC ,( Scott Riegel, L.GT..G. Proje Manager Attachments: Plate 1 —Vicinity Map Plate 2 — Test Pit Location Plan Test Pit Logs Grain Size Distribution Kyle R. Campbell, P.E. Principal Earth Solutions NW, LLC Reference NORTH Edmonds, Washington Map 474 By The Thomas Guide Rand McNally 32nd Edition 4 VP NOTE: This plate may contain areas of color. ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black & white reproductions of this plate. Drwn. MRS Date 08/14/2015 Proj. No. 3960.01 Checked AZS Date Aug. 2015 Plate 1 NORTH NOT - TO - SCALE NOTE: The graphics shown on this plate are not intended for design purposes or precise scale measurements, but only to illustrate the approximate test locations relative to the approximate locations of existing and / or proposed site features. The information illustrated is largely based on data provided by the client at the time of our study. ESNW cannot be responsible for subsequent design changes or interpretation of the data by others. LEGEND TP -1 I Approximate Location of ESNW Test Pit, Proj. No. ES -3960, June 2015 q i Subject Site Existing Building Earth Solutions N W LLc Test Pit Location Plan Cheeks Short Plat Edmonds, Washington NOTE: This plate may contain areas of color. ESNW cannot be Drwn. MRS Date 08/14/2015 Proj. No. 3960.01 responsible for any subsequent misinterpretation of the information resulting from black & white reproductions of this plate. Checked AZS Date Aug. 2015 Plate 2 Earth Solutions NLLC SOIL CLASSIFICATION CHART MAJOR D1VIS11 GRAVEL AND GRAVELLY SOILS COARSE GRAINED SOILS MORE THAN 50% OF COARSE FRACTION RETAINED ON NO. 4 SIEVE MORE THAN 50% SAND OF MATERIAL IS AND LARGER THAN SANDY NO. 200 SIEVE SOILS SIZE MORE THAN 50% OF COARSE FRACTION PASSING ON NO. 4 SIEVE DUAL SYMBOLS are used to indicate borderline soil classifications. The discussion in the text of this report is necessary for a proper understanding of the nature of the material presented in the attached logs. SILTS FINE AND GRAINED CLAYS SOILS DESCRIPTIONS MORE THAN 50% OF MATERIAL IS WELL -GRADED GRAVELS, GRAVEL - SMALLER THAN NO. 200 SIEVE SAND MIXTURES, LITTLE OR NO SIZE SILTS AND CLAYS HIGHLY ORGANIC DUAL SYMBOLS are used to indicate borderline soil classifications. The discussion in the text of this report is necessary for a proper understanding of the nature of the material presented in the attached logs. SYMBOLS TYPICAL ONS GRAPH LETTER DESCRIPTIONS CLEAN WELL -GRADED GRAVELS, GRAVEL - GRAVELS GW SAND MIXTURES, LITTLE OR NO # FINES v ** **ba POORLY -GRADED GRAVELS, (LITTLE OR NO FINES) p GP GRAVEL- SAND MIXTURES, LITTLE OR NO FINES GRAVELS WITH NJ 0 ** GM SILTY GRAVELS, GRAVEL -SAND - FINES O SILT MIXTURES (APPRECIABLECLAYEY GC GRAVELS, GRAVEL - SAND - AMOUNT OF FINES) CLAY MIXTURES CLEAN SANDS SW WELL -GRADED SANDS, GRAVELLY SANDS, LITTLE OR NO FINES POORLY -GRADED SANDS, (LITTLE OR NO FINES) SP GRAVELLY SAND, LITTLE OR NO FINES SANDS WITH y SM SILTY SANDS, SAND - SILT FINES MIXTURES SL' CLAYEY SANDS, SAND - CLAY AMOUNT OF FINES) MIXTURES INORGANIC SILTS AND VERY FINE ML SANDS, ROCK FLOUR, SILTY OR CLAYEY FINE SANDS OR CLAYEY SILTS WITH SLIGHT PLASTICITY INORGANIC CLAYS OF LOW TO LIQUID LIMIT`+L MEDIUM PLASTICITY, GRAVELLY LESS THAN 50 CLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLAYS OL ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY INORGANIC SILTS, MICACEOUS OR MH DIATOMACEOUS FINE SAND OR SILTY SOILS INORGANIC CLAYS OF HIGH LIQUID LIMITCII GREATER THAN 50 PLASTICITY OH ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTS SOILS ' ''-•"� pT PEAT, HUMUS, SWAMP SOILS WITH u •i� HIGH ORGANIC CONTENTS DUAL SYMBOLS are used to indicate borderline soil classifications. The discussion in the text of this report is necessary for a proper understanding of the nature of the material presented in the attached logs. Earth Solutions NW TEST PIT NUMBER TP-1 1805 -136th Place N.E., Suite 201 Bellevue, Washington 98005 PAGE 1 OF 1 Telephone: 425-449-4704 Fax: 425-449-4711 CLIENT Hi h oirC Vrnvesl'm-.�.ents _LC __... _.�.� w. PROJECT NAME Cheeks Short Plat._n PROJECT NUMBER 3960.01 PROJECT LOCATION Edmnneic Wachinntnn _ ._ ........ _.......w :...._� .DATE STARTED 6/15/15 .�M �_._.. ....e.-.. .,._. _...W.�.................. _ ........ m... 6/15/15 GROUND ELEVATION _ ......_ TEST PIT SIZE _. COMPLETED ...._ EXCAVATION CONTRACTOR NW Excavatina GROUND WATER LEVELS: EXCAVATION METHOD AT TIME OF EXCAVATION — LOGGED BY AZS CHECKED BY KDH AT END OF EXCAVATION — NOTES ,Wt ep h 9 T'op it l : pa `' moss m ro .. .....,,.m,, ... AFTER EXCAVATION — w z w ui EL Lu " g TESTS r, a 0 MATERIAL DESCRIPTION (L ¢z O w 0 PSL °� � 0 5 TOPSOIL ._..__-............_..___...._.........._._......._.........�._._.�. ..._._... ... m .... d Brown silty SAND, loose to medium dense, moist = MC 10.00% SM -roots a.o �� -...... _.__._ .__... _..m .._.. _ __ ., ..�.............._.......... Tan poorly graded SAND with ��ravel, medium dense, moist MC = 7.00% 5 SP 5,5 Brown poorly graded SAND with silt and gravel, medium dense to dense, moist MC = 5.20% SP_ SM MC = 9.00% MC = 6.80% s_s _ roundwater encountered during g ter Test pit terminated at 9.5 feet below existing grade. Noen excavation. Bottom of test pit at 9.5 feet. i 00 �a is i J F Earth solutions NW TEST PIT NUMBER TP -5 1805 -136th Place N.E., Suite 201 PAGE 1 OF 1 Bellevue, Washington 98005 11WTelephone: 425-449-4704 Fax: 425-449-4711 CLIENT Hiahoomt Investments, LLC a „m,IT..._. PROJECT NAME -Cheeks Short Plat PROJECT NUMBER 3960.01„ ...6/15115.._..._�...�........___--,..�.w PROJECT LOCATION Edmonds Washinoton DATE STARTED COMPLETED 6115/15 a GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: EXCAVATION METHOD.m.. _ .w.._... AT TIME OF EXCAVATION . — ..._., r ,..,�..... LOGGED BY AZS..... m..... CHECKED BY KDH AT END OF EXCAVATION-- �,. _....,� ........_... NOTES pgMof Topsoil- & Sod -8": forest�rt��?f _ ..,,, . w AFTER EXCAVATION Lu o- v _ �w U� _ wTESTS ai O MATERIAL DESCRIPTION 0 p- D Q z C7 C0 o TPSL ` = ` 0 5 TOPSOIL _ ... e nse, moist medium de Brown poorly graded SAND with silt, loose to dense, MC = 7.00% SP - SM 5 s.o Gray well graded GRAVEL with sand, medium dense, moist MC 3.10% Fines = 0.60% 'i [USDA Classification: extremely gravelly coarse SAND] GW Ir 10 MC = 4.20% �....... during Test 't terminated at 10.0 feet below existing grade. No groundwater encounteredi excavation. bj Bottom of test pit at 10.0 feet. Earth Solutions NW TEST PIT NUMBER TP -6 1805 - 136th Place N.E., Suite 201 PAGE 1 OF 1 Bellevue, Washington 98005 Telephone: 425-449-4704 Fax: 425-449-4711 CLIENT liiahooirat. Investments. LLC y. _ PROJECT NAME Cheeks Short Platu ...._ .. . PROJECT NUMBER 3960.01 PROJECT LOCATION Edmonds.W aehinatoo ._.a DATE STARTED µ,6/15/15 COMPLETED 6/m15/15 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavatipa GROUND WATER LEVELS: EXCAVATION METHOD m w ...e.... ,m ... AT TIME OF EXCAVATION LOGGED BY _AZS _ .. M. .... CHECKED BY KDHu AT END OF EXCAVATION -- � �. � ... _........ NOTES Depth of Topsoil A Sod 4 forest duff _ITIT AFTER EXCAVATION -- w _ �w v W U TESTS O co MATERIAL DESCRIPTION z c� Q to 0 TPSL = o.5 TOPSOIL � ..... _ � �........ _�... _._. .. ...�......� ..... , , . _..w._...__._.. ............. --- ,�v Brown silty SAND, loose, moist = MC 9.80% SM d.o _ �� Gray poorly graded SAND, loose to medium dense, m�..,.�.�n._. oast MC = 4.50% SP �� '� MC 4.10% RF Test pit terminated at 8.5 feet below existing rade. No g ..�....ater ncou a„_ -r , during � g g groundwater encountered during excavation. Bottom of test pit at 8.5 feet. N Z_ 'a (7 d J a H m Z W 0 Earth Solutions NW TEST PIS" NUMBER TP -7 1805 - 136th Place N.E., Suite 201 PAGE 1 OF 1 Bellevue, Washington 98005 q0WTelephone: 425-449-4704 Fax: 425-449-4711 iahnoint Investments LLC CLIENT I I_. a _ ..... ........ m. _ PROJECT NAME Cheeks Short Plat ......_.._.,.,.,., ..w�. .... ......m_... PROJECT NUMBER 3960.07 ..w.. _._.. ,,...__. .._ Edmonds Wasl�ington ..... �. �, PROJECT LOCATION ATI m N m � ....:. .. .. �. ......, _ ., ._ DATE STARTED 6/15/15.,., COMPLETED 6/15/15 _....., GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR NW ExcavatingGROUND WATER LEVELS: EXCAVATION METHOD .__.. AT TIME OF EXCAVATION LOGGED BY AZS CHECKED BY KDH AT END OF EXCAVATION „— NOTES Denth of Toeso lmm& Sod 2 rasa ...._ .,,. _..._ AFTER EXCAVATION - _w ,.a . .... _ mm .... ,.... _. ... .... ,. W _W N = w w g TESTS 0-0 MATERIAL DESCRIPTION z 0 Cn n TPSL `- 1, 0-5 TOPSOIL __..__a.� ._...... ,, n.— ------ _... ...... Tan silty..SAND, loose tom . _A... , medium dense, moist MC = 11.00% SM CO............ W ...... �.. a..... ..... a .. e........_ � ... _. ..... ..._... Brown poorly graded SAND, medium dense, moist MC = 9.70% _.... SP - - MC = 6.40% 9' Test pit terminated at 9.0 feet below existing grade. No groundwater n ..,�m water encountered during ng excavation. Bottom of test pit at 9.0 feet. o Lz z t� s oa Earth Solutions NW GRAIN SIZE DISTRIBUTION 1805 -136th Place N.E., Suite 201 MW U P" 1 Bellevue, WA 98005 Telephone: 425-284-3300 CLIENT HiahDoint Investments LLC1O1_e , _..... _ �__..... PROJECT NAME Cheeks ShortPlat PROJECT NUMBER ES -3960.01 PROJECT LOCATION Edmonds- .. ........... .. U,S. SIEVE OPENING IN INCHE..�..._.._�e.�._m�..._ ._...... ._...._ �........ � ... A._.. S I U.S. SIEVE NUMBERS I HYDROMETER 6 4 3 2 1 314 1123/8 3 4 6 810 1416 20 30 40 50 60 100140920 100 95 .... _... ...... ._ .mA, ...... 90 85 .... _ ........ _. ., .r .. wr _.,_...._ _ _. _ .. _ _ _ .... w .... .... 8075 .a .w_ _ .... ..... ....... .. ... _._ ...... ._ _._. _. ..... . 70 65 C? 60 w .. _ �. _ _ w.....m _... _ _ .. ...... ........ _ .__ �...,.I m55 o: w 50 z LL F- 45 _. m. ,, ... _ .... e_ ...., .,...... _ _,.... ,... �m ....... __._ - .... ... a ...... . ... ...... ........ _._,.....,. z w U 40 .......... ...... w a i 35 30 20� ._ 15 10 5 0 100 10 1 0.1 0.01 0.001 GRAIN SIZE IN MILLIMETERS ._-., COBBLES GRAVEL SAN D ..... .. __.. SILT OR CLAY coarse fine coarse medium fine- ----------- - ecimen Identification TP -5 6.Oft. ification Cc Cu USDA. Gra Extreme) GravellyCoarse � �� Sand. USCS: GW w Sand. 2.68 31.43 ....30 Specimen Identification D100mmn D60 D10 LL PL PI D e...... ___w ... .. _..--- ... TP -5 6.0ft- 37.5 12.209 3.563 0.388 %Silt I %Clay 0.6