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01CLS021 (07/08) AMERICAN ENGINEERING TESTING, INC. UNIFIED SOIL CLASSIFICATION SYSTEM ASTM Designations: D 2487, D2488 AMERICAN ENGINEERING TESTING, INC. Criteria for Assigning Group Symbols and Group Names Using Laboratory TestsA Soil Classification Notes ABased on the material passing the 3-in (75-mm) sieve. BIf field sample contained cobbles or boulders, or both, add “with cobbles or boulders, or both” to group name. CGravels 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 DSands 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 (D30)2 ECu = D60 /D10, Cc = D10 x D60 FIf soil contains >15% sand, add “with sand” to group name. GIf fines classify as CL-ML, use dual symbol GC-GM, or SC-SM. HIf fines are organic, add “with organic fines” to group name. IIf soil contains >15% gravel, add “with gravel” to group name. JIf Atterberg limits plot is hatched area, soil is a CL-ML silty clay. KIf soil contains 15 to 29% plus No. 200 add “with sand” or “with gravel”, whichever is predominant. LIf soil contains >30% plus No. 200, predominantly sand, add “sandy” to group name. MIf soil contains >30% plus No. 200, predominantly gravel, add “gravelly” to group name. NPl>4 and plots on or above “A” line. OPl<4 or plots below “A” line. PPl plots on or above “A” line. QPl plots below “A” line. RFiber Content description shown below. Group Symbol Group NameB Coarse-Grained Soils More than 50% retained on No. 200 sieve Gravels More than 50% coarse fraction retained on No. 4 sieve Clean Gravels Less than 5% finesC Cu>4 and 1<Cc<3E GW Well graded gravelF Cu<4 and/or 1>Cc>3E GP Poorly graded gravelF Gravels with Fines more than 12% fines C Fines classify as ML or MH GM Silty gravelF.G.H Fines classify as CL or CH GC Clayey gravelF.G.H Sands 50% or more of coarse fraction passes No. 4 sieve Clean Sands Less than 5% finesD Cu>6 and 1<Cc<3E SW Well-graded sandI Cu<6 and/or 1>Cc>3E SP Poorly-graded sandI Sands with Fines more than 12% fines D Fines classify as ML or MH SM Silty sandG.H.I Fines classify as CL or CH SC Clayey sandG.H.I Fine-Grained Soils 50% or more passes the No. 200 sieve (see Plasticity Chart below) Silts and Clays Liquid limit less than 50 inorganic PI>7 and plots on or above “A” lineJ CL Lean clayK.L.M PI<4 or plots below “A” lineJ ML SiltK.L.M organic Liquid limit–oven dried <0.75 Liquid limit – not dried OL Organic clayK.L.M.N Organic siltK.L.M.O Silts and Clays Liquid limit 50 or more inorganic PI plots on or above “A” line CH Fat clayK.L.M PI plots below “A” line MH Elastic siltK.L.M organic Liquid limit–oven dried <0.75 Liquid limit – not dried OH Organic clayK.L.M.P Organic siltK.L.M.Q Highly organic soil Primarily organic matter, dark in color, and organic in odor PT PeatR 3 2 ½1 ¾4 10 20 40 60 140 200 100 80 60 40 20 0 0 20 40 60 80 100 81 Sieve NumberScreen Opening (in.) 50 10 5 1.0 0.10.5 PARTICLE SIZE IN MILLIMETERS SIEVE ANALYSIS PERCENT PASSINGPERCENT RETAINEDD60 = 15mm D30 = 2.5mm D10 = 0.075mm Cu = = = 200D60 D10 15 0.075 Cc = = = 5.6(D30) D10 x D60 2.5 0.075 x 15 2 2 CL-ML For classification of fine-grained soils and fine-grained fraction of coarse-grained soils. Equation of "A"-line Horizontal at PI = 4 to LL = 25.5. then PI = 0.73 (LL-20) Equation of "U"-line Vertical at LL = 16 to PI = 7. then PI = 0.9 (LL-8)"A" LIN E "U" LINECL OR OL CH OR OH 10 20 30 40 50 60 70 80 90 100 110 0 0 10 20 30 40 50 60 16 7 4PLASTICITY INDEX (PI)LIQUID LIMIT (LL) Plasticity Chart ADDITIONAL TERMINOLOGY NOTES USED BY AET FOR SOIL IDENTIFICATION AND DESCRIPTION Grain Size Term Particle Size Boulders Over 12" Cobbles 3" to 12" Gravel #4 sieve to 3" Sand #200 to #4 sieve Fines (silt & clay) Pass #200 sieve Gravel Percentages Term Percent A Little Gravel 3% - 14% With Gravel 15% - 29% Gravelly 30% - 50% Consistency of Plastic Soils Term N-Value, BPF Very Soft less than 2 Soft 2 - 4 Firm 5 - 8 Stiff 9 - 15 Very Stiff 16 - 30 Hard Greater than 30 Relative Density of Non-Plastic Soils Term N-Value, BPF Very Loose 0 - 4 Loose 5 - 10 Medium Dense 11 - 30 Dense 31 - 50 Very Dense Greater than 50 Moisture/Frost Condition (MC Column) D (Dry): Absence of moisture, dusty, dry to touch. M (Moist): Damp, although free water not visible. Soil may still have a high water content (over “optimum”). W (Wet/ Free water visible, intended to Waterbearing): describe non-plastic soils. Waterbearing usually relates to sands and sand with silt. F (Frozen): Soil frozen Layering Notes Laminations: Layers less than ½" thick of differing material or color. Lenses: Pockets or layers greater than ½" thick of differing material or color. Peat Description Fiber Content Term (Visual Estimate) Fibric Peat: Greater than 67% Hemic Peat: 33 – 67% Sapric Peat: Less than 33% Organic Description (if no lab tests) Soils are described as organic, if soil is not peat and is judged to have sufficient organic fines content to influence the Liquid Limit properties. Slightly organic used for borderline cases. Root Inclusions With roots: Judged to have sufficient quantity of roots to influence the soil properties. Trace roots: Small roots present, but not judged to be in sufficient quantity to significantly affect soil properties. ML OR OL MH OR OH Draft