地震动的强烈不确定性使得高拱坝在满足设计地震烈度要求的前提下必须深入研究超载地震动作用下的抗震裕度。本文通过对考虑横缝的高拱坝在不同强度地震动下响应的分析,得到大坝在逐级增强的地震动作用下,拱冠顺河向位移和输入加速度呈现出分3段变化的规律。由此提出了拱坝整体抗震性能的3个阶段水平。同时,地震动峰值加速度也是一个随机变量,本文考虑了这个随机性,计算了拱坝在考虑某大小地震作用下处于某一功能水平的概率。相比于搜索拱坝在强震作用下具有较强随机性的失效路径的方法而言更有可操作性,本文在解决超静定拱坝在强震下的整体抗震性能评价指标方面提出了有益的参考。
It is necessary to thoroughly investigate the ultimate seismic capacity of dam under rare strong earthquake. The seismic responses of arch dam with transverse joints, under increasing levels of earthquakes, are studied using FEM model. Based on this analysis, 3 stages division in holistic seismic performance of arch dam is recommended. Considering the uncertainty of peak ground acceleration, the probability of arch dam in certain performance stage is calculated, and the result may be very useful for the seismic evaluation of arch dam, comparing with the approach of searching all the failure modes/paths. The preliminary study may give some hints in finding seismic performance evaluation index.