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UNIFIED SOIL CLASSIFICATION SYSTEM (USCS) <br />COARSE GRAINED SOILS <br />(Less than 50°h fines. Fines are soils pauing the It 200 sievc,) <br />GROUP SYMBOL DESCRIPTION MAJOR DNISIONS <br />GW � Wel4graded GRAVELS or GRAVEL• , <br />�. SAND miutures, less than 5% fines. � <br />GP Poorfy graded GRAVELS or GRAVE4 <br />SAND mi�rtures, kss lhan 5%fines. � <br />GM Silty GRAVELS, GRAVEL-SANDSILT ' <br />� miMures, more than 12%fines. <br />� Clayey GRAVELS, GRAVEL- SAND-SILT� <br />' mixtures, more ihan 12°,b fines. <br />SW I Wel4gratled SANDS or Gravely SANDS � <br />miNures, less than 5%fines. <br />Poody graded SANDS or Gravelly �� <br />SANDS mutures, less than 5% (nes. � <br />GC <br />SP <br />SM Silry SANDS, SAN0.SILT mintures, � <br />morethanl2%fines. i <br />SC Clayey SANDS, SAN0.CLAY mirtures, �I <br />more than 12% fines <br />GRAVELS <br />More than haM ol coarse fradan is <br />larger than No. 4 sieve. <br />SANDS <br />More lhan haM of coarse haqion is <br />smallerihan No. 4 sieva. <br />Nole: Coarse-grained soils ieceive dual symbols H they contain beMeen 5 antl 12 percent fines. <br />FINE-GRAINED SOILS <br />(hbre than 50°� fines. Fines afe materials passing Ihe N 200 sieve) <br />GROUP SYMBOL DESCRIPTION MAJOR DIVISIONS <br />M� Inorganic SILTS, very (ne SANDS, <br />ROCK FLOUR, Sitty or Clayey SANDS <br />Inorganic CLAYS ot low to medium SILTS and CLAYS <br />C� plasticity, Gravelly CLAYS, Sandy <br />CLAYS, Silly CLAYS, Lean CLAYS Liquid limit iess than 50 <br />OL �, Organic SILTS, or o�ganic Sitty CLAYS of <br />Iow plasticity <br />I Inorganic SILTS, Micaceous or � <br />MH ' Diatomaceous fine SANDS or SILTS, <br />Elastic SILTS <br />CH <br />OH <br />PT <br />Inorganic CLAYS of hyh plaslidty, fat , <br />CLAYS <br />Organic CLAYS of ineAium to hgh � <br />plasticity <br />PEAT, MUCK, and other hghy organic <br />soils <br />SILTS and CLAYS <br />Liquid limit greater than 50 <br />Highly organic soils <br />Note: Fine-greined soils receive dual symbols H their limRs plot lefl of the'A" Line and have a plasticiry index (PI) of 4 to 7 I <br />percent. <br />UNIFIED SOIL CLASSIFICATION SYSTEM <br />Otto Rosenau 3 Associates, <br />Inc. <br />A7 ��1� <br />