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WS UNIFIED SOIL CLASSIFICATION AND SYMBOL CHART LABORATORY CLASSIFICATION CRITERIA COARSE-GRAINED SOILS (more than 50%of material is larger than No.200 sieve size.) Clean Gravels{Less than 6%fines D D &GW Well-graded gravels,gravel-sand GW Cu= DG0 greater than 4;C = D %� between 1 and 3 GRAVELSmixtures,little or no flnes10 10 60 More than 50% Poody-graded gravels,gravel-sand of coarse mixtures,little or no fines GP Not mee ling all gradation requirements for GW fraction larger Gravels with fines Mare than 121I tines than Mo.4 sieve size !GIMA Silty gravels,gravel-sand-silt mixtures GM Atterbarg limitsbelow"A"line or P.I.less than 4 pbave"A"tins with P.l.6ekween 4 and 7 are borderline cases Clayey gravels,gravel Silty GC Atterherg limits above"A" requiring use of dual symbols mixtures line with R1,greater than 7 I Glean Sands Less than 5%fines D D 3n SW Welt graded sands,gravelly sands, SW Cu= D greater than 4;Cc= D x D between 1 and 3 little or no fines 10 1ta fi0 SANDS 50%or more Sp Poorly graded sands,gravelly sands, of coarse Itille or no fines Sp Not meeting all gradation requirements for GW fraction smaller Sands with flnes(Mare than 12%fines) than No.4 sieve size -,Sands Silty Sands,sand-At mixturesSilty sands,sand-silt mixtures SM Atterberg limits below"A" Limits plotting in shaded zone line or P.I,less than 4 with P.I.between 4 and 7 are ''''" Atterberg limits above"A" borderline cases requiring use 'r SC Clayey sands,sand-clay mixtures SC of dual symbols, line with P.I.greater than 7 FINE-GRAINED SOILS (50% or more of material is smaller then No.200 slave size,) Determine percentagesof sand and gravel from grain-size curve. Depending on percentage of fines(fraction smaller than Mo.200 sieve size), Inorganic silts and very fine sands,rock coarse-grained soils are classified as follows: SILTS ML flour,silty of clayey tine sands or clayey Less than 5 percent . .................. ,...,......GW,GP,SW,SIP silts with slight plast€city More than 12 percent;;.:. .;:, .. ............ GM,GC,SM,SG AND CLAYS n Inorganic clays of Saw to medium 5 to 12 percent...... . Borderline cases requiring dual symbols ;.a, Liquid limit -': CL plasticity,gravelly clays,sandy clays, less than '5: silly clays,teen clays PLASTICITY CHART 50% OL Organic silts and organic silty clays of 60 low plasticily Inorganic silts,mioaceous or a 50 CH MH diatomaceous line sandy or silty soils, SILTS elastic sills u 40 A LINE; AND 30 Pl a 0 73(LL-20) CLAYS CH Inorganic.clays of high plasticity,fat CL MhI I OH Liquid limit clays 50% c) 20 or greater J r OFt Organic clays of medium to high 10 plasticity,organic silts ML&OL HIGHLY 00 10 20 30 40 50 60 70 80 90 100 ORGANIC PT Peal and other hlgMy organic soils LIQUID LIMIT(LL)(°A) SOILS a,,