Effects of Bedrocks on the Dynamic Response of Concrete Gravity Dams Subjected to Underwater Explosions

Reservoirs and dams often play critical roles in economics and politics. They are frequently considered as the primary targets during wartime or in terrorism attacks. In this study, the behaviors of concrete gravity dams subjected to underwater explosions are numerically investigated. Three-dimensional finite element models are developed according to the design drawings of a concrete gravity dam built in China. The effects of an underwater explosion, including the shock wave and bubble oscillations, are modeled based on the pressure time-histories. The water is modeled using the acoustic method, for which the propagation of the pressure histogram is well reproduced as an acoustic wave. The concrete dam is modeled using solid elements. The damage and failure of the concrete are reproduced by the damage-plasticity model with strain rate dependence. To investigate the influence of bedrocks, three types of numerical models are developed, which are validated by comparing the predictions with the centrifuge tests on a scale concrete gravity dam. Systematic numerical results indicate that the developed numerical model is capable of capturing the features of concrete gravity dams subjected to underwater explosions. Furthermore, the bedrocks play an important role in the dynamic responses of the dams. Thus, the bedrocks should be considered for the accurate modeling of the underwater explosion systems of concrete gravity dams.