Defence Technology (Sep 2023)
The damage to model concrete gravity dams subjected to water explosions
Abstract
Over the past century, the safety of dams has gradually attracted attention from all parties. Research on the dynamic response and damage evolution of dams under extreme loads is the basis of dam safety issues. In recent decades, scholars have studied the responses of dams under earthquake loads, but there is still much room for improvement in experimental and theoretical research on small probability loads such as explosions. In this paper, a 50-m-high concrete gravity dam is used as a prototype dam, and a water explosion model test of a 2.5-m-high concrete gravity dam is designed. The water pressure and the acceleration response of the dam body in the test are analysed. The pressure characteristics and dynamic response of the dam body are assessed. Taking the dam damage test as an example, a numerical model of concrete gravity dam damage is established, and the damage evolution of the dam body is analysed. By combining experiments and numerical simulations, the damage characteristics of the dam body under the action of different charge water explosions are clarified. The integrity of the dam body is well maintained under the action of a small-quantity water explosion, and the dynamic response of the dam body is mainly caused by the shock wave. Both the shock wave and the bubble pulsation cause the dam body to accelerate, and the peak acceleration of the dam body under the action of the bubble pulsation is only one percent of the peak acceleration of the dam body under the action of the shock wave. When subjected to explosions in large quantities of water, the dam body is seriously damaged. Under the action of a shock wave, the dam body produces a secondary acceleration response, which is generated by an internal interaction after the dam body is damaged. The damage evolution process of the dam body under the action of a large-scale water explosion is analysed, and it is found that the shock wave pressure of the water explosion causes local damage to the dam body facing the explosion. After the peak value of the shock wave, the impulse continues to act on the dam body, causing cumulative damage and damage inside the dam body.
