中文摘要：

近半个世纪以来，中国成为世界上建坝数量最多的国家。需要评估爆炸荷载对于大坝的安全的影响。本文为研究水下不同炸点接触爆炸对混凝土重力坝上游有折坡段和上游无折坡段两种坝型的动力响应以及破坏状态影响，进行了两种坝型的混凝土重力坝水下接触爆炸的动力响应及损伤破坏特性的对比分析。利用数值模拟方法计算了炸药在空气中爆炸对于混凝土板的损伤破坏，并与物理实验的结果进行对比。通过计算结果对比验证了所使用数值模型的正确性和可靠性。以混凝土重力坝上游有折坡段和上游无折坡段两种坝型为研究对象，考虑炸药-库水-空气-混凝土重力坝结构之间的动力耦合关系，对比分析了水下接触爆炸冲击荷载作用下，两种坝型的挡水坝段坝体的动态响应及损伤破坏分布特性。通过对比分析可知：混凝土重力坝上游有折坡段的挡水坝段减小了水下接触爆炸对坝体的加速度、速度及位移的动力响应。混凝土重力坝上游无折坡比有折坡坝型的挡水坝段在水下接触爆炸冲击荷载作用下损伤范围更大、更为严重。通过以上结果可得到结论：混凝土重力坝上游折坡段可以有效地散射爆炸产生的应力波，减小混凝土重力坝的损伤破坏程度。

英文摘要：

In the past half century, China has constructed more dams than any other country in the world. The impact of the blast load on the safety of a concrete dam needs to be assessed. The effects of different locations for underwater contact explosion on two different types of concrete gravity dams with and without folding slope on upstream face were compared and studied. Firstly, the numerical model was given to simulate the explosion response of concrete slabs in air and the damage and failure state of the concrete slabs. Through the comparative analysis of physical experiments and numerical experiments of damage to concrete slab results, the accuracy and reliability of the numerical model used in this study were verified. Then,taking concrete gravity dam as the research subject, by considering the dynamic coupling relationship of explosive-reservoir water-air-structure of the concrete gravity dam, analysis was made on the dynamic response and damage property of the two different types of gravity dams with and without folding slope on upstream face subject to un- derwater contact explosion. And the results showed the folding slope on upstream face of gravity dam decreases the dynamic responses of acceleration, velocity and displacement. Furthermore, the damage of gravity dam without folding slope was more serious subject to under- water contact explosion on upstream face. The results also showed that the folding slope on upstream face of gravity dam could effectively absorb the stress wave generated by the explosion and effectively reduce the damage of concrete gravity dam.