A nonlinear analysis of dynamic interactions of CFRD–compressible reservoir system based on FEM–SBFEM

Reservoir water compressibility is a major factor affecting dynamic dam–reservoir interactions, and most studies focus on the analysis of concrete dams. However, few studies have been conducted with respect to the effects of reservoir water compressibility on the dynamic response of CFRDs (concrete-faced rockfill dams). Furthermore, new researches show the hydrodynamic pressure is significant for evaluating the seismic performance of high CFRD. In this paper, a method to calculate the nonlinear dynamic interactions of CFRD–compressible reservoir water system in the time-domain is established based on a FEM–SBFEM approach. The CFRD is discretized using the finite element method (FEM), and the hydrodynamic pressure of the semi-infinite water on the upstream face of the dam is calculated using the efficient scaled boundary finite element method (SBFEM), in which the degrees of freedom of the hydrodynamic pressure to be solved for are relatively few. The objective of this work is to investigate the effects of reservoir water compressibility and the sediment absorption layer at the reservoir bottom and bank slopes on the dynamic response of a high CFRD–reservoir-coupled system under seismic action in various directions. When the reservoir water is considered compressible, partial absorption of the hydrodynamic pressure wave by the sediments can be considered. The results show that water compressibility can significantly affect the stress in the face slabs.