Soil Classification System

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Added on 2020-03-04

Soil Classification System

Added on 2020-03-04

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Running Head: UNIFIED SOIL CLASSIFICATION SYSTEM (USCS)Unified Soil Classification SystemName Institution Date

Running Head: UNIFIED SOIL CLASSIFICATION SYSTEM (USCS)Unified Soil Classification System (USCS) classified soils into coarse grained and fine grained categories. Under coarse grained soils which are those where more than 50% is retained in No.200 sieve, soils are further subdivide into sands and gravels depending on the percentage passing No.4 sieve. Fine grained are those that allow 50% or more to pass through No.200 sieve and are categorized into silts and clays with a liquid limit of less than 50 and those with a liquid limit of 50 or more. These can also be further classified into well graded and poorly graded. Gravels that have a coefficient of curvature between 1 and 3 and a coefficient of uniformity greater or equal to 4 are classified as well graded gravels.Sands that have a coefficient of curvature between 1 and 3 and a coefficient of uniformitygreater or equal to 6 are classified as well graded sands.DefinitionsPlasticity Index measures a soil’s plasticity and is calculated as the difference between the liquid limit and the plastic limit. The plasticity chart is used to classify using this.CoefficientofUniformity,Cu=D60D10CoefficientofCurvature,Cc=(D30)2D10∗D60Where;D30 = grain diameter at 30 percent passingD60= grain diameter at 60 percent passing

Running Head: UNIFIED SOIL CLASSIFICATION SYSTEM (USCS)D10= grain diameter at 10 percent passingCalculations and conclusions1)Soil from borrow pit B1D10=¿0.00002D30 = 0.0015 D60 = 0.014Cu=D60D10¿0.0140.00002=700Cc=(D30)2D10∗D60 = .001520.00002+.014 = 0.016Percentage passing the No. 200 sieve (0.075 micron) = 16%.Percentage passing the No. 4 sieve (0.00475 micron) = 41%. Liquid Limit was found to be 43 %Plastic Limit was found to be 18 %Plasticity Index = 43 – 18 = 25. Permeability was not acquiredThis soil is coarse grained and is therefore a gravel since the percentage passing sieve No.200 is less than 50% and that passing sieve No.4 is less than 50% . It is also well graded

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