考虑行波效应的混凝土高坝系统地震分析与损伤评价

Seismic Analysis and Damage Evaluation of High Concrete Dam System Considering Effect of Traveling Wave

为研究地震动行波效应的影响,基于时程分析的数值方法,对国内某高坝系统在强震作用下的动力响应进行模拟,即引入等效三维一致粘弹性人工边界,推导了计入水流向行波效应的地震动输入公式,将等效荷载作用于人工边界对行波输入进行验证;考虑坝体和基岩材料非线性,结合与规范相统一的混凝土本构和能量等效性假设,推导出归一化混凝土本构与损伤因子的对应关系;模拟库水可压缩性和坝体伸缩横缝的开合非线性,以不耦合损伤变量的简化地震损伤评估方法进行安全评价。结果表明,上部坝肩和左、右侧边表孔顶部是抗震的薄弱部位,不考虑水流向行波效应对高坝抗震设计偏保守。

To study the effect of seismic traveling wave,numerical method based time history analysis was applied to carry out the finite element simulation of the earthquake dynamic response for a domestic high dam system.With three-dimensional equivalent viscous-spring boundary,the formula of seismic motion input considering the effect of traveling wave in flow direction was deduced.And then the equivalent load was acted on the artificial boundary to evaluate the wave input method.Considering the material nonlinearity of dam and rock foundation,the corresponding relationship between the normalized concrete constitutive and damage factor was deduced by combining with concrete constitutive relation of unity of specification and the energy equivalence hypothesis.Furthermore,the reservoir water compressibility and contact nonlinearity of contraction joint opening and closing states were simulated.The simplified earthquake damage assessment method which is not coupled with damage variable was adopted for seismic safety evaluation.The results show that the upper dam abutment and the top of surface spillways in left and right side are more vulnerable under earthquake action,and it is partial conservative for high dam anti-seismic design without considering the effect of travelling wave.