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CLASSIFICATION of SOILS for ENGINEERING PURPOSES <br />ASTM Designation D-2487 and D2488 (Unified Soil Classification System) <br />Major Divisions <br />Course Grained Soils <br />Fine Grained Soils <br />More than 50% retained on No. 200 sieve <br />More than 50% passes No. 200 sieve * <br />50% or more of coarse fraction <br />More than 50% of coarse fraction <br />retained on No. 4 sieve. <br />passes No 4 sieve. <br />a) <br />co <br />(9 <br />ro <br />ro <br />v <br />os <br />N <br />Clean Sands <br />4-4 <br />co <br />Group <br />Symbol <br />Typical Name <br />Well —graded gravels and <br />GW gravel -sand mixtures, little <br />or no fines. <br />Poorly graded gravels and <br />GP gravel -sand mixtures, little <br />or no fines. <br />GM <br />GC <br />SW <br />SP <br />SM <br />SC <br />ML <br />CL <br />Silty gravels, gravel -sand - <br />silt mixtures. <br />Clayey gravels, gravel -sand - <br />clay mixtures. <br />Well -graded sands and <br />gravelly sands, little or no <br />fines. <br />Poorly -graded sands and <br />gravelly sands, little or no <br />fines. <br />Silty sands, sand -silt <br />mixtures. <br />Clayey sands, sand -clay <br />mixtures. <br />Inorganic silts, very fine <br />sands, rock flour, silty or <br />clayey fine sands. <br />Inorganic clays of low to <br />medium plasticity, gravelly <br />clays, sandy clays, silty <br />clays, lean clays. <br />OL <br />Organic silts and organic <br />silty clays of low plasticity. <br />MH <br />CH <br />OH <br />Inorganic silts, micaceous <br />or diatomaceous fine sands <br />or silts, elastic silts. <br />Inorganic clays of high <br />plasticity, fat clays. <br />Organic clays of medium to <br />high plasticity. <br />Pt <br />Peat, muck and other <br />highly organic soils. <br />Brookview Estates Reconstruction <br />Ramsey, Minnesota <br />NTI Project No. 18.MSP06855.000 <br />Classification Criteria <br />0 <br />0- <br />0- U N <br />CD <br />c <br />c a ( <br />w (7 0 m <br />O � 8 <br />w o o ca <br />CID <br />(5 <br />ra <br />a+ °� <br />u • > in <br />0 <br />0. <br />0 <br />m <br />0 <br />0 <br />cn <br />ro <br />v <br />m 0 <br />O 8 O O <br />rsi <br />oN o z <br />z <br />z °° m i <br />C N 0) <br />m <br />sz N o Atterberg limits <br />• ti <br />- below "A" line, or <br />c o E <br />" P.I. less than 4. <br />L m ' m Atterberg limits <br />E <br />o o above "A" line <br />J " o with P.I. > 7. <br />Plasticity Index Chart <br />(00 O O 000 CV <br />0 <br />}lual1 APPRssld <br />Cu = D60 / D10 greater than 4. <br />Cz = (D30)2 / (D10 x D60) between 1 & 3. <br />Not meeting both criteria for GW materials. <br />Atterberg limits <br />below "A" line, or <br />P.I. less than 4. <br />Atterberg limits <br />above "A" line <br />with P.I. greater <br />than 7. <br />Atterberg limits <br />plotting in hatched <br />area are borderline <br />classifications <br />requiring use of dual <br />symbols. <br />Cu = D60 / D10 greater than 6. <br />Cz = (D30)2 / (D10 x D60) between 1 & 3. <br />Not meeting both criteria for SW materials. <br />Atterberg limits <br />plotting in hatched <br />area are borderline <br />classifications <br />requiring use of dual <br />symbols. <br />1 <br />OH Soils <br />O <br />O <br />rn <br />co <br />0 <br />O <br />O <br />N <br />• 0 <br />— V <br />o <br />O <br />J <br />0 <br />cr <br />J <br />