Liquefaction Behavior of Typical River Channel Deposit in Kolkata City

Abstract

Liquefaction susceptibility of river channel deposit in Kolkata city is studied using laboratory cyclic triaxial tests. River channel deposit, which supports a large part of rapidly growing urbanization of Kolkata city, mainly consists of sandy soil with little amount of silt. Cyclic triaxial tests have been performed on this soil sample with varying relative density, confining pressure, and cyclic strain amplitude. Results are presented to show how these parameters influence the pore water pressure generation within soil. Relative density, confining pressure and cyclic strain amplitude are found to affect the pore pressure generation characteristics in the soil, and the number of cycles required to reach liquefaction phenomena vary significantly. Finally, pore pressure generation characteristics are modeled using a hyperbolic model and a pore pressure generation equation is proposed for the typical river channel deposit soil. The model exhibits a certain threshold value of cyclic strain amplitude, up to which the initial rate of pore pressure generation decreases and then increases.