cstion 3 The natural soils along a proposed highway alignmen

cstion #3 The natural soils along a proposed highway alignment have a particle size distribution as described by curve A in the figure below, a liquid limit of 44, a plastic limit of 21, and is inorganic. Determine the USCS soil classification FINES SAND GRAVEL Fine Medium Coarse Fine Coarse #200 #4 100 90 70 E 60 40 30 20 10 0.001 0.01 10 100 Particle sie mm)

Solution

Simply read the curve, and corresponding standard given by USCS. Following observations can be made.:

% Passing(Finer) than no. 200 (0.075mm) = 55% i.e. >50%, so it is fine grained soil.

LL = 44 i.e. <50 and PI = 44-21 = 23 i.e. >7

A-line, PI = 0.73(LL-20) = 0.73(44-20) = 17.52, so it lies above A-line.

So the soil classification is CL(Lean Clay)