Effects of reservoir-bottom explosion on concrete gravity dam and potential mitigation measure

As an essential infrastructure, dams may suffer explosive loads during their lifecycle. To reveal the dynamic response characteristics of concrete gravity dam (CGD) under reservoir-bottom explosions and explore potential mitigation measures, a 1:100 concrete gravity dam model was poured, and eight test scenarios under different explosion distances, water depths and detonation depths were designed. The time-history curves of water pressure, acceleration, and velocity under different test scenarios were recorded and compared to better understand the dynamic response of CGD under reservoir-bottom explosions. In addition, bubble curtains were used as a potential measure to mitigate the effects of underwater explosions on CGD. The results indicate that the maximum peak acceleration of the dam happens at the water's surface elevation. The smaller the explosion distance or the more profound the water depth, the more intense the response of the CGD. Compared with the reservoir-bottom explosion, the response of the CGD is stronger when the explosion is suspended in water. Arranging a bubble curtain on the upstream surface can significantly mitigate the reservoir-bottom explosion effects on the dam, and the peak accelerations are reduced by 92.0–99.5 %. This paper can provide important references for studying the dynamic response of CGD under reservoir-bottom explosions and corresponding mitigation measures.