Failure modes of concrete gravity dam subjected to near-field underwater explosion: Centrifuge test and numerical simulation

Abstract

Concrete gravity dams are often referred to as vertical cantilever structures with approximately fixed bottoms due to their massive gravity, frictions with the foundation, and additional anti-sliding techniques. Given this, when modeling concrete gravity dams subjected to underwater explosions, should the dam bottom be considered as the fixed boundary or the frictional boundary? In this study, two small-scale centrifuge tests and numerical simulations were used to investigate the dam failure modes due to near-field underwater explosions. Emphasis was placed on the effect of dam bottom boundary condition (DB-BC) to improve understanding of dam failure mechanisms and provide references for constructing experimental and numerical dam models. To this end, the current research began with a combined experimental and numerical investigation on the failure modes of dams with fixed bottoms. Then, a numerical study was conducted to evaluate the effect of DB-BC. Results revealed that dams with frictional bottoms demonstrated essentially the same failure mode as those with fixed bottoms. Both exhibited mainly the structural bending-induced tensile failure mode. To the authors’ knowledge, this is the first time the effect of DB-BC has been explored. In particular, by centrifuge tests, this paper presented the urgently needed experimental data in this field including dam failure patterns and strain histories as well as test videos.