Soil Compression Index Prediction Model for Fine Grained Soils

Compressibility of a soil mass is its susceptibility to decrease in volume under pressure and is indicated by soil characteristics like coefficient of compressibility, compression index and coefficient of consolidation. However, the determination of soil compressibility characteristics in the labs is a cumbersome and time consuming process, especially in the case of fine grained soils. In the present study, an attempt has been made to estimate compression index as a function of soil index properties. Soil samples were collected from different Indian hydropower projects. The collected samples were subjected to laboratory investigations for the determination of geotechnical parameters namely liquid limits, plastic limits and compression indices. Based on experimental results, correlations between the soil index properties (liquid limit & plasticity index) and compression index were evaluated. An empirical model was developed to estimate the compression index as a function of liquid limit and plasticity index. The model results were compared with the actual compression index values, as determined by laboratory tests, and were found to be in good agreement. The compression index values for the collected samples were also determined using the available models in literature, and the results indicate that the present model can predict the soil compressibility more accurately.