Dynamic stability of concrete structures with varying sections to underwater contact explosion: A case study of gravity dams

Concrete structures with varying sections are widely used in the fields of ocean engineering, hydraulic engineering and civil engineering. And the damage mechanism of variable-section structures to underwater contact explosion, which involves localized damage by explosion impact and instability by overall structural vibration, is very complex. The gravity dam is taken as an example, the coupled analysis model for gravity dams under underwater contact blast is established, a prototype test on the dynamic response of a gravity dam under underwater explosion is conducted to verify the reliability of the fluid-solid interaction method, and the reliability of the concrete dynamic damage model adopted in this paper is validated by a small-scale field test on the internal blast damage of a gravity dam. The damage mechanism of gravity dams subjected to underwater contact explosion is analyzed. A stability analysis method for gravity dams to underwater contact explosion is proposed, which allows simultaneous consideration of the dam stability in the blast-induced vibration phase and the static phase after damage. The dynamic stability performance of gravity dams to underwater contact explosion is analyzed. And a stability assessment criterion that could be used to assess the safety level of dams at various stages is presented.