A series of dynamic centrifuge model tests on clay tailings reservoir as well as the reservoir after expanding has been performed in a centrifuge shaker. The seismic behavior examined in this study includes the acceleration amplification

variations in the pore water pressure both in soft clay foundation and in clay tailing

deformation of the soft ground-clay tailing-tailings dam system. The experimental results indicate that the acceleration amplification by the soft clay ground is limited

while the acceleration response increases with height for the tailings dam. The strongest acceleration response occurs at the highest sub-dam

especially at the highest one of the tailings dam after expanding. There is an increase in pore water pressure induced by earthquake both in soft ground and in clay tailing

but no liquefaction occurs. The ground motion

soft foundation and the consolidation state of tailings in the reservoir have great influence on the deformation mode of tailings reservoir. If the soil is not sufficiently consolidated and the earthquake is strong enough

horizontal movement of the clay tailing and rise of soft clay in the downstream can occur. Seismic settlement can be found if the soil is sufficiently consolidated and the shaking is relatively weak. The experimental results can provide a reference for the seismic analysis of this kind of tailings reservoir.