GENERATION OF PORE PRESSURE AND MATERIAL RESPONSE OF FINE GRAINED SOILS UNDER CYCLIC LOADS

This paper discusses the effect of pore-water pressure of fine-grained soils on failure behavior. For this purpose a series of dynamic triaxial tests were performed on natural medium-high plasticity clay specimens taken from the in-situ boreholes under groundwater levels. Two different dynamic loading sequences were used under isotropic stress conditions. In terms of cyclic strain amplitude the failure criteria is assumed as ±2.5%. Excess pore water pressure accumulation was recorded at the time of failure and were analyzed considering different soil parameters. It has been concluded that, besides the shear stress value, the pore water pressure behaviour has changed significantly by mineralogy of the soil sample. For practical purposes, a pore water pressure model is proposed