ABSTRACT
After a reservoir having run a period of time, a sediment layer will be deposited before its dam. The studies of the effects of sediment layer on the hydrodynamic pressures of impounded water and the seismic responses of dam are less, and the factor is not almost considered in the seismic design of dams to be constructed and the assessment of earthquake safety of existing dams. A common action of sediment layer and foundation is modeled as a partial energy absorption boundary while considering the compressibility of impounded water in the less research materials. In the paper, it is revealed that sediment layer not only has the energy absorption effect, but also has the inertia amplification effect for the responses of dynamic pressures of water and sediment induced by vertical ground motion on dams through studying for a series of theoretically models and verifying of the test on indoor shaking table. With increasing of the thickness and porosity of sediment, the frequency corresponding to the inertia amplification effect appears to vary gradually. The comprehensive idea in the paper is important for further improving the analytical model and method of seismic responses of dams.
