Liquefaction susceptibility of cohesionless soils under monotonic compression and cyclic simple shear loading at drained/undrained/partially drained modes

Abstract

Liquefaction susceptibility of cohesionless soils is influenced by various factors such as stress state, loading conditions, and shearing modes, and therefore, the implicit assumption of completely undrained shearing modes could pose damaging consequences. In the current research, the effect of stress state and shearing modes on liquefaction response of cohesionless soils was studied under monotonic compression and cyclic simple shear loading conditions. Undrained, drained, and partially drained shearing modes were applied on three different silty sands collected from three different locations of earthquake-prone region of Kutch. The partially drained shearing mode was applied at different effective stress ratios (ESRs) to simulate different stress states. All three silty sands exhibited undrained instability at large ESR values. The effect of cyclic stress ratio (CSR) on liquefaction response of cohesionless soils was also evaluated by conducting cyclic simple shear tests. Soil specimens from all the three locations exhibited liquefaction due to the generation of large excess pore water pressure of greater than 95% of the loss in effective stress. The number of cycles required to initiate liquefaction decreased and the rate of development of pore water pressure increased with the increase in the applied CSR under cyclic simple shear loading conditions.