Behavior of Weathered Soil under Combined Undrained Cyclic-Monotonic Loading

Liquefied soils are considered as soils devoid of any strength or having only limited strength. Post-liquefaction shear behavior of soil before the drainage of excess pore pressure is important in predicting the immediate performance of foundation and soil structures subjected to liquefying loads. In the present study, the post-cyclic undrained behavior of weathered silty sand was examined under triaxial test conditions. The soil showed complete strength recovery after subjecting it to monotonic shearing up to large strains. The post-liquefaction shear behavior was mostly determined by the amount of excess pore pressures that developed during cyclic loading. The cyclic load amplitude and shear strain did not seem to have an effect on the post-cyclic shear behavior. Post-cyclic shearing showed that with sufficient strain the soil recovered its original strength even without dissipation of any excess pore pressure.