Analysis of the Fracture Mechanism of Concrete Gravity Dams under Explosive Loading

As a critical strategic target and a large hydraulic structure, the dynamic response of concrete gravity dams under explosive loading has been extensively studied, yielding mature research results. However, there remains a gap in understanding the damage process and mechanisms. This study conducts contact explosion experiments on concrete gravity dam models with varying explosive charges and detonation locations. Coupled with simulation calculations, the fracture process and fracture path characteristics of the dam body are analyzed. Additionally, based on the elastoplastic theory of concrete, the study quantitatively calculates the damage surface of the dam structure under different conditions. The similarity degree between the damage surface and the fracture path of the dam body is analyzed using curve similarity algorithms (PCM, DTW, etc.), thereby investigating the fracture mechanism of the dam. The results indicate that when large-scale fractures occur in concrete dams under explosive loading, the starting points of the fracture path of the remaining dam body typically locate in the transition zone outside the crushing zone. The fracture mechanism of this process tends more toward a mode I-II composite fracture, which involves the combined effects of opening-mode and sliding-mode fractures.