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

•A combined experimental and numerical study on the failure modes of concrete gravity dams subjected to near-field underwater explosions.•The first time the effect of dam bottom boundary condition has been explored.•The concrete gravity dam bends downstream and demonstrates mainly the structural bending-induced tensile failure mode with tensile fractures visible in the dam body.•A fixed dam bottom rather than a frictional one is preferred when constructing experimental and numerical dam models.