The following test results were obtained for a fine-grained soil:
WL= 48% ; WP = 26%
Clay content = 55%
Silt content = 35%
Sand content = 10%
In situ moisture content = 39% = w
Classify the soil, and determine its activity and liquidity index
Plasticity index, IP = WL– WP = 48 – 26 = 22%
Liquid limit lies between 35% and 50%.
According to the Plasticity Chart, the soil is classified as CI, i.e. clay of intermediate plasticity.
Liquidity index , = = 0.59
The clay is of normal activity and is of soft consistency.