Laserfiche WebLink
1 UNIFIED SOIL CLASSIFICATION SYSTEM <br /> Soil Classification I <br /> Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests A Group Symbol <br /> Group Name6 <br /> Sy '1 Gravels: Clean Gravels: Cu>_4 and 1 <_Cc<_3 E GW Well-graded gravel F <br /> More than 50%of Less than 5%fines C Cu<4 and/or 1 >Cc>3 E GP Poorly graded gravel F <br /> coarse fraction retained Gravels with Fines: Fines classify as ML or MH GM Silty gravel F.c." <br /> Coarse Grained Soils: on No.4 sieve More than 12%fines c Fines classify as CL or CH GC Clayey gravel F°.H I <br /> More than 50%retained <br /> on No.200 sieve Sands: Clean Sands: Cu-6 and 1 <Cc<- 3 E SW Well-graded sand' <br /> 50%or more of coarse Less than 5%fines° Cu<.6 and/or 1 >Cc>3 E SP Poorly graded sand' <br /> fraction passes No.4 Sands with Fines: Fines classify as ML or MH SM Silty sand c."'' I <br /> sieve More than 12%fines° Fines classify as CL or CH SC Clayey sand G"' <br /> PI>7 and plots on or above"A"lined CL Lean clay K.L,M <br /> Inorganic: K,1 M I <br /> Silts and Clays: PI<4 or plots below"A"lined ML Silt <br /> Liquid limit less than 50 Liquid limit-oven dried Organic clay L,M." <br /> Fine-Grained Soils: Organic: <0.75 OL K.L.M.o <br /> 50%or more passes the Liquid limit-not dried Organic K LIB <br /> No.200 sieve PI plots on or above"A"line CH Fat clay I <br /> Inorganic: <br /> K,L.M <br /> Silts and Clays: PI plots below"A"line MH Elastic Silt <br /> Liquid limit 50 or more Liquid limit-oven dried Organic clay K,L,M.P <br /> Organic: <0.75 OH K,L.M O <br /> Liquid limit-not dried Organic silt <br /> Highly organic soils: Primarily organic matter,dark in color,and organic odor PT Peat I <br /> A Based on the material passing the 3-in. (75-mm)sieve "If fines are organic,add"with organic fines"to group name. <br /> B If field sample contained cobbles or boulders,or both,add"with cobbles ' If soil contains>_ 15%gravel,add"with gravel"to group name. <br /> or boulders,or both"to group name. ' If Atterberg limits plot in shaded area,soil is a CL-ML,silty clay. <br /> c Gravels with 5 to 12%fines require dual symbols: GW-GM well-graded K If soil contains 15 to 29%plus No.200,add"with sand"or"with gravel," <br /> gravel with silt,GW-GC well-graded gravel with clay,GP-GM poorly whichever is predominant. <br /> graded gravel with silt,GP-GC poorly graded gravel with clay. L If soil contains>-30%plus No.200 predominantly sand,add"sandy"to <br /> °Sands with 5 to 12%fines require dual symbols: SW-SM well-graded group name. <br /> sand with silt,SW-SC well-graded sand with clay,SP-SM poorly graded M If soil contains=30%plus No.200,predominantly gravel,add <br /> sand with silt,SP-SC poorly graded sand with clay "gravelly"to group name. <br /> (D )2 "PI>4 and plots on or above"A"line. I <br /> E Cu=D60/D10 Cc= 30 °PI<4 or plots below"A"line. <br /> D10 x D60 P PI plots on or above"A"line. <br /> F If soil contains,15%sand,add"with sand"to group name. °PI plots below"A"line. <br /> O If fines classify as CL-ML, use dual symbol GC-GM,or SC-SM. I <br /> 60 • <br /> For classification of fine-grained <br /> soils and fine-grained fraction <br /> 50 of coarse-grained soils •�ce,'' �e . I <br /> v, \, <br /> Equation of"A"-line ,J,1" �•P <br /> d Horizontal at P1=4 to LL=25.5. O <br /> X 40 - ( ) <br /> then PI-o.73 LL-20 I <br /> pEquation of"U"-line �oc <br /> Z Vertical at LL=16 to P1=7, G <br /> 30 then PI=0.9(LL-8) ,, <br /> o 1 , Ov <br /> U) 20 . Goo <br /> Q <br /> n_ MHorOH <br /> 10 r' <br /> 7 ---�OBbI� <br /> 4 MLorOL 1 <br /> 0 <br /> 0 10 16 20 30 40 50 60 70 80 90 100 110 <br /> LIQUID LIMIT (LL) <br /> Exhibit C-2 1 <br />