基于破坏形态的重力坝地震易损性研究

大坝的地震风险分析是评价和改进大坝抗震安全度的有效工具.大坝的地震易损性是指大坝在给定地震荷载作用下发生各级损伤的条件概率,是地震风险研究（地震危险性分析、地震易损性分析、地震灾害损失评估）的3个主要组成部分之一.在考虑混凝土材料细观层次非均匀性影响的基础上,通过对碾压混凝土重力坝强震损伤破坏形态和过程的大量数值模拟,总结提炼了重力坝的典型震害形态,并据此提出了重力坝的五级震害等级划分标准.结合大坝设计地震超越概率,提出了大坝易损性分析方法,给出了金安桥重力坝挡水坝段的地震易损性曲线.研究结果可为混凝土重力坝的抗震设计和加固决策等提供参考.

Analyses of failure modes-based seismic fragility of gravity dams

Seismic risk analysis is an effective method to evaluate and improve the seismic safety of dams.Seismic fragility analyses can describe the conditional probabilities of structural damage caused by different levels of earthquakes.It is one of three issues(seismic hazard analysis,seismic fragility analysis and seismic loss assessment) of seismic risk analyses.By considering meso-level influence of concrete heterogeneity,large amount of nonlinear time-history analyses of rolled compacted concrete gravity dam under strong earthquake are performed.Typical failure modes of gravity dam are concluded and a five-level standard for seismic damage of gravity dam is put forward.Combined with non-exceedance probabililty of design earthquake for the dam,the seismic fragility curve for retaining dam section of Jin’anqiao dam is obtained.This research is helpful to optimize seismic design,reinforcement and maintenance measures and improve aseismic capability of the dam.