Abstract: Reservoir bottom wave absorption is an important part of the interaction in a gravity dam-foundation-reservoir system. In this study, the absorption is simulated using an acoustic structure coupling method and impedance boundary conditions. An example verification analysis shows that an accurate curve of hydrodynamic pressure distribution over the dam surface can be obtained in the case of different coefficients of reservoir bottom reflection at the same excitation frequency or the case of these coefficients taking the same value at different excitation frequencies. Analysis of the new Fengman gravity dam supports the conclusion that the reflection coefficient has significant influence on the pressure distribution, and an increase in the coefficient will enhance the amplitude of hydrodynamic pressure and consequently the dynamic response of the dam. The influence of the old Fengman dam, located in the upstream, on the new one is examined, revealing the existence of the old dam brings about significantly larger amplitudes in the variations of hydrodynamic pressure over the whole surface of the new dam.

Key words: gravity dam, acoustic structure coupling, impedance boundary conditions, reservoir bottom absorption, hydrodynamic pressure, dynamic response of dam