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SOIL TYPES(Ref.l)
<br /> Boulders: Particles of rock that will not 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#4 sieve,but not a#200 sieve.
<br /> Silt Soil that will 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 term;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-#40 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-#40 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 limit,i.e.the range in water contents over which the
<br /> soil is in a plastic state.
<br /> MEASURES OF CONSISTENCY OF COHESIVE SOILS(CLAYS) (Ref's 2&3)
<br /> Very Soft N=0-1* C=0-250 psf Squeezes between fingers
<br /> Soft N=24 C=250-500 psf Easily molded by finger pressure
<br /> Medium Stiff N=5-8 C=500-1000 psf Molded by strong finger pressure
<br /> Stiff N=9-15 C=1000-2000 psf Dented by strong finger pressure
<br /> Very Stiff N=16-30 C=200011000 psf Dented slightly by finger pressure
<br /> Hard N>30 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 N=0-4** RD=0-30 Easily push a 1/2-inch reinforcing rod by hand
<br /> Loose N=5-10 RD=30-50 Push a 1/2-inch reinforcing rod by hand
<br /> Medium Dense N=11-30 RD-50-70 Easily drive a 1/2-inch reinforcing rod
<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-pound weight,
<br /> divide the blow count by 2 to get N(Ret 4).RD=Relative Density
<br /> Ref.l: ASTM Designation:D 2487-93,Standard Classification of Soils for Engineering Purposes(Unified Soil
<br /> Classification System).
<br /> Ref.2: Terzaghi Kul,and Peck,Ralph B.,Soil Mechanics in Engineering Practice,John Wiley&Sons,
<br /> New York, 2nd Ed.,1967,pp.30,341,347.
<br /> Ref.3: Sowers,George F.,Introductory Soil Mechanics and Foundations:Geotechnical Engineering,
<br /> cm
<br /> Maillan 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 Nostrand Reinhold Company,New York,2nd Ed,1991,p.39/
<br /> �. Lathrop Effluentnds Earth Systems Consultants SOIL TERMINOLOGY
<br /> �j Percolation po
<br /> Northern California Lathrop,California Figure 2
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