2002-11-05_REVISION - M2001107 - Laserfiche WebLink

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UNIFIED SOIL CLASSIFICATION SYSTEM Criteria for Assigning Group Symbols and Group Names Using Lahoratory Tests' Coarse Grained Soils Gravels Clean Gravels More than 50 % retained More than 50 % o(coarse Less than 5 % fines` fraction retained on on No. 200 sieve No. 4 sieve Gravels with Fines More than 12 % foes` Fine-Grained Soils 50 % or more passes the No. 200 sieve Sands Clean Sands 50 % or more of coarse less than 5 % fnes° fraction passes No. 4 sieve Sands with Fines More than 12 %fines° Silts antl Clays inorganic Liquitl limit less than 50 organic Silts and Clays inorganic Liquid limit 50 or more organic soils Cu z4 and15Ccs 3` Cu < 4 andPor i > Cc > 3` Fines classify as ML or MH Fines Uassity as CL or CH Cu >_6and15Ccs3` Cu < 6 and/or t > Cc > 3' Fines classify as ML or MH Fines classify as CL or CH PI > 7 and plats on er above "A" line' PI < 4 ar plots below "A" line' Liquid limit -oven dried <0.75 Liquid limit -not dried PI plats on or above "A" line PI plots below'A' line Liquid limit -oven dried < 0.75 Soil Classification Group Symhol Group Name' GW Well graded gravel` GP Poorly graded gravel` GM Siity gravel°~6~" GC Clayey gravel"" SW SP Well graded sand' Poony graded sand' SM Silly sand"' SC Clayey sand`"' CL Lean Uay"`" ML Silt"`" OL Organic clay"`"" Organic siltK~"'0 CH Fat clay"~`" MH Elastic silt"'`"' OH Organic Uay"~"`° Organic siltKLLO PT Peat Liquid limit -not dried Primarily organic matter, dark in color, and organic odor "Based on the material passing the 3-in. (75-mm) sieve °If field sample contained cobbles or boulders, or both, add "with cobbles or boulders, or both' to group name. °Gravels with 5 to 12%fines require dual symbols: GW-GM well graded gravel with silt, GW-GC well graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay. °Sands with 5 to 12%fines require dual symbols: SW-SM well graded sand with silt, SW-SC well graded sand with clay, SP-SM poorly graded sand with silt, SP-SC poorly graded sand with clay z Dio x Deo ° If soil contains z 15% sand, add "with sand" to group name. °If fines classify as CL-ML,~use dual symbol GC-GM, or SC-SM. - 60 50 a W 40 O Z ~ 30 U F- N p° J a to 7 4 a 0 10 1fi p 30 40 50 60 70 LIQUID LIMIT (LL) BO 90 "If fines are organic, add "with organic fines' to group name. I If soil contains s 15% gravel, add'With gravel" to group name. ~ I(Atterberg limits plot in shaded area, soil is a CL-ML, silty clay. "If sail contains 15 to 29% plus No. 200, add 'with sand' or "with gravel," whichever is predominant. ~If soil contains >_ 30% plus No. 200 predominantly sand, add "sandy" to group name. "' If soil contains >_ 30% plus No. 200, predominantly gravel, add "gravelly" to group name. "PI z 4 and plots on or above "A" line. ° PI <4 or plots below "A" line. °PI plots on or above "A" line. ° PI plots below "A" line. For classification of fine-grained soils and fine-grained fraction of coarse-grained soils co ~~ o Equation of"A'-line ~ ,J~,i~ + ~\~ P Horizontal al PI=4 to LL=25.5. Inen PI=0 73 (LL-20) ~ . C• Equation of "U' -line o~ ~ Vertical al LL=16 to PI=7, G - --- - - then PI.0.9 (LL-9) - - ' /' O~ , pt ~ G I I MHa I rOH --- _ ='-'a ML OL i I or 100 110 1 ~~rracon