Examining the effects of layering on the seismic behavior of tailings dams using dynamic centrifuge tests

This study aims to examine the effects of layering on the seismic behavior of tailings dams. The focus is put on the spatial distribution of excess pore pressure and its variations with time during earthquake loading. In order to achieve this, dynamic centrifuge tests have been carried out for tailings dam models with thin silty layers sandwiched in sandy tailings. The experimental results demonstrate that dense sandy tailings can be contractive under cyclic loading, generating excess pore pressure. The flow of liquid upwards to the slope surface and the dissipation of excess pore pressure in the tailings can be inhibited or slowed by the overlying silty layer. The tailings covered by silty layers at shallower locations may exhibit a more pronounced increase in the ratio of excess pore pressure over initial effective vertical stress, leading to a more significant reduction in the stiffness and strength. This eventually may lead to liquefaction or failure of the slope. Those results can improve our understanding on the seismic behavior of tailings pond with thin silty layers, which is common in real mining projects.