Blast Performance and Damage Evaluation of High Arch Dams Subjected to Far-Field Underwater Explosions: Consideration of Joints

Abstract

The blast performance of 300-m-high arch dams is an important subject which has been studied widely over the years. An arch dam is convex on the upstream face, and the load is transmitted along the arch axis to the abutments at the ends of the dam. However, the integrity of arch dams is affected by the transverse contraction joints. The blast resistance performance of a 300-m-high arch dam subjected to far-field underwater explosion was investigated considering contraction joints. The acoustic–structural method was employed to model the underwater explosion loads and the interactions among the dam–reservoir–foundation system. To verify the reliability of the acoustic–structural method, a 1∶200-scale model of an arch dam subjected to far-field underwater explosion was tested. A zero-thickness cohesive element was employed to model the mechanical behavior of contraction joints with grouting. Nonlinear dynamic response and damage progress of the high arch dam with transverse contraction joints to the far-field underwater explosion were investigated in terms of peak displacement, velocity, and damage modes. The tensile damage mechanism of the arch dam subjected to the far-field underwater explosion was discussed. The damage modes and deformation mechanism of high arch dams at the different positions of initiation point were presented. A damage index based on the damaged area in the downstream face and foundation face is proposed to evaluate the blast performance of high arch dams subjected to far-field underwater explosions. The results show that the contraction joints have a certain influence on the nonlinear dynamic and damage modes of high arch dams subjected to the far-field underwater explosion. The damage is larger with explosive charges near the one-quarter arch ring in the weak stiffness bank due to the asymmetry of the arch dam.