Laserfiche WebLink
UNIFIED SOIL CLASSIFICATION SYSTEM <br />Criteria for Assigning Group Symbols and Group Names Using Lahoratory Tests° <br />Coarse Grained Soils Gravels Clean Gravels <br /> More than 50 % of coarse Less than 5% fines` <br />More than 50 % retained fraction retainetl on <br />on No. 200 sieve No. 4 sieve Gravels with Fines <br /> More than 12 % fines` <br /> Sands Clean Sands <br /> 50 % or mare of coarse Less than 5 % fines° <br /> fraction passes <br /> No. 4 sieve Sands with Fines <br /> More than 12 % fnes° <br />Fine-Grained Soils Silts and Clays inorganic <br />50% or more passes the Liquid limit less than 50 <br />No. 200 sieve <br /> organic <br />Silts and Clays inorganic <br />Liquitl limit 50 or more <br />organic <br />soils <br /> Group <br />Symbol <br />Cu?4 and 15Cc53` GW <br />Cu < 4 and/or 1 > Cc > 3r GP <br />Fines classify as ML or MH GM <br />Fines classify as CL or CH GC <br />Cu >_6andisCc<3` ~ SW <br />Cu < 6 antl/or 1 > Cc > 3` <br />Fines classify as ML or MH <br />Fines classify as CL or CH <br />PI > 7 antl plots on or above "A"line' <br />PI < 4 or plots below "A" line' <br />Liquid limit -oven <br />dried <g.75 <br />Liquid limit -not <br />PI plots on or above "A" line <br />PI plots below "A" line <br />Liquid limit -oven dried <br />< 0.75 <br />SP <br />SM <br />SC <br />CL <br />ML <br />OL <br />CH <br />MH <br />OH <br />PT <br />Soil Classification <br />Group Name° <br />Well graded gravel` <br />Poorly graded gravel` <br />Clayey gravelF6'" <br />Well graded sand' <br />Poorly gratled sand' <br />Silly sand°"' <br />Clayey sand°X1 <br />Lean clay"`"' <br />Silt"`" <br />Organic clay"`^'" <br />Organic silt"'~gO <br />Fat clay""" <br />Elastic silt"~~" <br />Organic clay"`"" <br />Organic silt"`"° <br />Peat <br />Liquid limit -not dried <br />matter, dark in color, and organic odor <br />"Based on the material passing the 3-in. (75-mm) sieve <br />elf feld sample contained cobbles or boulders, or both, add "with cobbles <br />or boulders, or both" to group name. <br />c Gravels with 5 to 12% fines require dual symbols: GW-GM well graded <br />gravel with silt, GW-GC well graded gravel with clay, GP-GM poorly <br />graded gravel with silt, GP-GC poorly graded gravel with clay. <br />°Sands with 5 to 12% fines require dual symbols: SW-SM well graded <br />sand with silt, SW-SC well graded sand with clay, SP-SM poorly graded <br />sand with silt, SP-SC poorly graded sand with clay <br />)~ <br />ECu = DedDio Cc = (D°° <br />Di° x Dso <br />r If soil contains >_ 15% sand, add "with sand" to group name. <br />olf fines classify as CL-ML, use dual symbol GC-GM, or SC-SM. <br />60 <br />50 <br />a <br />w ao <br />0 <br />z <br />r ao <br />U <br />F- <br />Q 20 <br />J <br />a <br />ro <br />7 <br />a <br />0 <br />0 <br />"If fines are organic, add "with organic floes" to group name. <br />~ If soil contains 2 15% gravel, add "with gravel" to group name. <br />~ If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay. <br />Klf soil contains 15 to 29% plus No. 200, add "with sand" or "with <br />gravel," whichever is predominant. <br />`If soil contains z 30% plus No. 200 predominantly sand, add <br />"sandy" to group name. <br />m If soil contains z 30% plus No. 200, predominantly gravel, <br />add "gravelly" [o group name. <br />"PI 2 4 and plots on or ahove "A" line. <br />o PI < 4 or plots below "A" line. <br />PPI plots on or above "A" line. <br />o PI plots below "A" line. <br />10 16 20 30 40 60 EO 70 BO 90 <br />LIQUID LIMIT (LL) <br />tbo no <br />l~~rracon <br />