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UNIFIED SOIL CLASSIFICATION SYSTEM Major GroupTypical Field Identlflcation Procedures Information Required for Divisions Symbols Names (excluding particles larger than 3 inches Describing Soils and basing fractions on estimated weights) 1 2 3 4 5 6 2 8 GW Well-graded gravels gravel sand mixtures little or Wide range in grain saes and substantial amounts of For undisturbed soils add information on I c3 no lines ail intermediate panicle saes stratification degree of compactness cementation i? moisture cond}tions and drainage characteristics GP Poorly graded gravels or gravel sand mixtures little Predominantly one size or a range of sizes with some or no fines intermediate sizes missing Z GM Silty gravels gravel sand silt mrxlure Nonplastic fines or fines with low plasticity Give typical name Indicate approximate rh S (for identification procedures see ML below) percentage of sand and gravel maximum size b LL angularity,surface condition,and hardness of the n $ GC Clayey gravels gravel sand clay mixtures Plastic fines(for identihcalion see CL below) coarse grains local or geologic name and other e pertinent descriptive information and symbol in SW Well graded sands gravelly sands little or no Wide range in gram size and substantial amounts of parentheses 2S 5 S lines all intermediale particle sizes 3 i? SP Poorly graded sands or gravelly sands little or no Predominantly one size or a range of saes with some Example fines intermediate sizes missing Silly sain gravelly about 20%hard angular gravel particles 112 in maximum size,rounded and SM Silty sands sand silt mrstures Nonplastic lines or tines with low plasticity subangular sand grains course to fine,about 4% ggg (for ideft0ficatwn procedures see ML below) nonplastic fines with low dry strength,well $ compacted and moist in place alluvial sand,(SM) SC Clayey sands sand clay mixtures ��`fines( for Identification procedures see CL Identification Procedures on Fraction Smaller then No 40 Sieve Size m Ory Strength Dtlatancy Toughness m (Crushing (Reaction (Consistency characteristics) 10 shaking) near PL) ML Inorganic silts and very line sands,rack flour silty None to slight Ouick to slow None For undisturbed soils add information on structure or clayey line sands or clayey silts with slight stratification,consistency In undisturbed and c plasticity remolded states moisture and drainage conditions 3 CL Inorganic clays of low 10 medium plasticity gravetiy Medium to None to very Medium F 4 clays sandy clays silty clays lean clays high slow g OL Organic silts and organic silty clays of low Slight to Slow Slight Give typical Hama militate degree and Character plasticity medium of plasticity,amount and maximum size of coarse grains color In wet condition odor N any local or '$ MH Inorganic silts micaceous or diatomaceous line Slight to Slow to none Slight to geologic name and other pertinent descriptive e sandy or silty sods elastic silts medium medium information,and symbol In parentheses ffiCH Inorganic clays of high plasticity lat clays High to None High rd very high OH Organic days and stlts of medium to high plasticity Medium to None to Slight to Example high very slow medium Cla___vav siiL brown slighty plastic,small percentage of fine sand numerous vertfcat root holes firm and Highly Organic Soils Pt Peat and other highly organic soils Readily Identified by color odor,spongy feel and dry in place,loess,(ML) frequently by fibrous texture RWXAS9oc ATM