中文摘要：

本文采用非线性地震波动分析方法，将坝体、地基、库水的强震反应作为满足体系中接触面边界约束条件的波传播问题求解，以坝体位移反应发生突变作为拱坝体系整体失稳判断准则，依据设计概率水平及实际可信超设计概率水平确定的地震动，对小湾拱坝的地震响应进行数值计算分析，给出其在不同水平地震作用下的抗震超载安全度。分析结果表明，该拱坝在实际可能发生的最大地震作用下，尚有1．3倍的超载裕度，其抗震安全性能满足设计要求。

英文摘要：

The nonlinear analysis method for wave propagation problem is applied to numerically study the seismic response of the high arch dam in the Xiaowan Hydro Project. The response of dam-foundation-reservoir system is regarded as the propagation of wave under the constraint of contact surface. The sudden increase of displacement is adopted as the criterion to determine the occurrence of failure of the dam. The calculated earthquake levels include the design probability level and the level with different exceeding probabilities. The analysis result shows that the factor of safety of the arch dam under the action of probable maximum earthquake is 1.3, which is in accordance with the requirement of design.