Failure analysis for concrete gravity dam subjected to underwater explosion: A comparative study

•Two types of numerical models are utilized to provide a cross validation of the failure analysis results.•The damage of the dam subjected to underwater explosion is mainly concerntrated directly opposite to the explosive resource.•The underwater explosion load still affects the failure behavior of dam even after the energy transmission at fluid–structure interface. The failure analysis of concrete gravity dams subjected to noncontact underwater explosions (UNDEXs) plays a significant role in evaluating the safety of dams. In this paper, two types of numerical models were developed to predict the failure behavior of a typical concrete gravity dam, i.e., the fully-coupled and semi-coupled model, which can provide a cross validation of the analysis results. The two models were verified by the experimental data and then adopted for the failure analysis. The results show that the shock wave can produce peak value in the blast responses and concentrated damage directly opposite to the explosive source. Even after the energy transmission at the fluid–structure interface, the UNDEX load still had influence on the failure behavior of the dam and can induce a total swelling in the velocity response.