Test: Unified Soil Classification - Civil Engineering (CE) MCQ

 In 1940, casagrande originally developed the unified soil classification system (USCS).

 In earlier stages of World War 2, the USCS system was used for air field construction.

According to USCS the fine grained soils, whose behavior is controlled by plasticity, are classified on the basis of their plasticity.

 Various soil are classified in to four major groups
1. Coarse grained
2. Fine grained
3. Organic soils
4. Peat.

If more than 50 % of the soil is retained on a NO.200 US sieve (0.075), it is designated as coarse grained soil.

 If the percentage of fines lies between 5 to 12 %, coarse grained soils are designated by dual symbols GW-GM or SP-SM.

Based on their liquid limit and plasticity index, fine grained soil are subdivided in to silt and clay

Based on the liquid limit and plasticity index, fine grained soil is subdivided.

Based on the soil size, coarse grained soil is divided in to gravel and sand.

 In Casagrande’s plasticity chart, the numbers denote relative suitability with No.1 as the best and No. 10 as the worst.