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SOIL TYPES(Ref.1)
<br /> Boulders: Particles of rock that will nm pass a 12-inch screen.
<br /> Cobbles: Particles of rock that will pass a 12-inch screen,but not a 3-inch sieve.
<br /> Gravel: Particles of rock that will pass a 3-inch sieve,but not a#4 sieve.
<br /> Sand: Particles of rock that will pass a M sieve,but not a#200 sieve.
<br /> Silt Soe that wi0 pass a#200 sieve,that is non-plastic or very slightly plastic,and that exhibits little or
<br /> no strength when dry.
<br /> Clay: Soil that will pass a#200 sieve,that can be made to exhibit plasticity(putty-like properties)within a
<br /> range of water contents,and that exhibits considerable strength when dry
<br /> MOISTURE AND DENSITY
<br /> Moisture Condition: An observational teen;dry,moist,wet.
<br /> Moisture Content: The weight of water in a sample divided by the weight of dry soil in the soil sample,expressed as a percentage.
<br /> Dry Density: The pounds of dry soil in a cubic foot of soil.
<br /> DESCRIPTORS OF CONSISTENCY(Ref.3)
<br /> Liquid Limit The water content at which a-#90 soil is on the boundary between exhibiting liquid and plastic
<br /> characteristics.The consistency feels like soft butter.
<br /> Plastic Limit: The water content at which a 440 soil is on the boundary between exhibiting plastic and semi-solid
<br /> characteristics.The consistency feels like stiff putty.
<br /> Plasticity Index: The difference between the liquid limit and the plastic lmuL i.e.the range in water contents over which the
<br /> .if is in a plastic state.
<br /> MEASURES OF CONSISTENCY OF COHESIVE SOILS(CLAYS) (Ref's 2&3)
<br /> Very Soft N=0-1• C=6250 psf Squeezes between fingers
<br /> Soft N=24 C=250-500 ps( FasRy molded by finger pressure
<br /> Medium Stiff N-w`8 C-2`00-1006 psf Molded by strong finger pressure
<br /> Stiff N915 C=1000-2000 psf Dented by strong finger pressure
<br /> Very Stiff N=1630 C=20004000 psf Dented slightly by finger pressure.
<br /> Hard N130 C>4000 psf Dented slightly by a pencil point
<br /> •N=Blows per foot in the Standard Penetration Test.In cohesive soils,with the 3-inch-diameter sampler.,140-pound weight,
<br /> divide the blow count by 1.2 to get N(Ref.4).
<br /> MEASURES OF RELATIVE DENSITY OF GRANULAR SOILS(GRAVELS,SANDS,AND SILTS)(Ref's 2&3)
<br /> Very Loose NdF RD-b-30 Easily push a 1/2-inch reinforcing rod by hand
<br /> Loose N=5-70 RD--30-50 Push a 1/2-inch reinforcing rad by hand
<br /> Medium Dense N=11-30 RD-50-70 Easily drive.]/2-inch reinforcing red
<br /> Dense N--=31-50 RD-70-90 Drive a 1/2-inch reinforcing rod 1 foot
<br /> Very Dense N>50 RD=90.100 Drive a 1/2-inch reinforcing rod a few inches
<br /> "N=Blows per foot in the Standard Penetration Test.In granular soils,with the 3-inch-diameter sampler,140-p000d weight,
<br /> divide the blow count by 2 to get N(Ref 4).RD=Relative Density
<br /> Ref.1: ASTM Designation:D 2487-93,Standard Classification of Soils for Engineering Purposes(Unified Soil
<br /> Classification System).
<br /> Ref.2: TernRhi,Karl,and Peck,Ralph B., Soil Mechanics in Engineering Practice,John Wiley&Sons,
<br /> New York, 2nd Ed.,1%7,pp.30,Ml,347.
<br /> Ref.3: Sowers,George R,Introductory Soil Mechanics and Foundations:Geotechnical Engineering.
<br /> Macmillan Publishing Company,New York,4th Ed.,1979,pp.80,81,and 312.
<br /> Ref 4: Lowe,John III,and Zaccheo,Phillip F,Subsurface Explorations and Sampling Chapter 1 in"Foundation Engineering
<br /> Handbook,'Hsai-Yang Fang,Editor,Van Nostoo d Reinhold Company,New York,2nd Ed,1991,p.39/
<br /> Earth systems Consultants Pombo/Cl comn SOIL TERMINOLOGY
<br /> '��! North.CalNornia Tracy,California Figure A2
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