Practice Question: Soil Classification Based on Sieve Analysis

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Solution

Refer to PE Civil Reference Handbook Section 3.7.2 for USCS Soil classification.

Determine whether the soil is silt and clays or sands and gravel based on the No. 200 sieve % passing.

#200 Sieve pass = 15 % → Soil is Coarse-Grained (Sands and Gravel) given more than 50% is retained at No.200 Sieve.
#4 Sieve pass = 82 % → Soil is Sandy given more than 50 % of coarse fraction passes No.4 Sieve.

Additionally, 
#200 Sieve pass = 15 % → Soil is Sandy with fines given No.200 Sieve pass greater than 12%.

Refer to Plasticity Chart for USCS (ASTM D 2487):

\[LL = 25\]

\[PL=10\]

\[Soil \ has \ CL\]

\[No. 4 \ retained = 100-82= 18 \% \to Gravel\]

From Page 118 of Handbook, Flow Chart to Determine the Group Symbol and Group Name for Coarse-Grained Soils (ASTM D 2487): 

→ Gravel Percent = 18 % then the USCS Classification = SC (Clayey Sand with Gravel)

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