The effects of reservoir geometry on the seismic response of gravity dams

Conventional seismic analysis of gravity dams assumes that the behaviour of the dam-water-soil system can be represented using a 2-D model since dam vertical contraction joints between blocks allow them to vibrate independently from each other. The 2-D model assumes the reservoir to be infinite and of constant width, which is not true for certain types of reservoirs. In this paper, a boundary element method (BEM) model in the frequency domain is used to investigate the influence of the reservoir geometry on the hydrodynamic dam response. Important conceptual conclusions about the dam-reservoir system behaviour are obtained using this model. The results show that the reservoir shape influences the seismic response of the dam, making it necessary to account for 3-D effects in order to obtain accurate results. In particular, the 3-D pressure and displacement responses can be substantially larger than those computed with the 2-D model.