水下爆炸冲击荷载作用下混凝土重力坝的破坏模式

Failure mode analysis of concrete gravity dam subjected to underwater explosion

考虑混凝土的高应变率效应,构建重力坝水下爆炸全耦合模型,运用显式动力分析程序LS-DY-NA,对水下爆炸冲击荷载作用下大坝动态响应进行分析,探讨大坝可能破坏模式及相应的破坏机制。研究表明,大坝破坏模式不仅与坝体的自身动力特性有关,还取决于炸弹起爆时的水下深度、爆心距及炸弹药量;重力坝坝头是抗爆性能薄弱部位,大坝可能破坏模式为上游迎爆面的爆炸成坑破坏、坝顶及坝下游面的震塌破坏、坝头与上游直面交接处及下游折坡附近的脆性冲切破坏并出现贯穿性裂缝破坏。

Strain rate effect of concrete dam was taken into consideration in the establishment of gravity dam fully coupled model by using software LS-DYNA. Numerical simulation method was used to study the dynamic response of the dam subjected to strong underwater explosion shock loading. The possible failure mode and corresponding failure mechanism of concrete gravity dam were discussed. It is found that the failure modes of dam under blast loading depend not only on its own dynamic charac- teristics, but also on the underwater depth, tlhe blast center distance and the bomb dosage. The head of a gravity dam is one of weak parts for antiknock performance. Possible failure modes of a dam in- clude explosion to pits at upstreamface concrete zones which meet explosive, explosion-induced collapse at crest and downstream, brittle punching at joint of the head and upstream planes and near the downstream slope with penetrating cracks.