基于变形的土石坝地震易损性分析

Seismic fragility analysis for earth-rockfill dams based on deformation

地震易损性分析是地震风险分析的重要组成部分,可以预测结构在遭受不同等级地震荷载作用下发生各级破损的概率。土石坝在地震作用下易发生不同程度的破坏,对其进行易损性分析可以为土石坝地震风险分析及评价提供有效途径。考虑土石坝材料参数及地震动输入不确定性因素的影响,提出了基于变形的土石坝地震易损性分析方法。采用正交设计法选取材料参数样本组合,分别施加不同地震峰值加速度进行地震反应分析,基于坝顶相对沉陷破损评价指标,给出了大坝的易损性曲线。以云鹏心墙土石坝为例进行了地震易损性分析,得到大坝不同震损等级的风险概率,对土石坝地震风险评估和抗震设计优化、维修加固决策等具有重要意义和应用价值。

Seismic fragility is an important part of seismic risk analysis, which can be adopted to predict the probabilities of structural damage induced by different levels of earthquakes. The fragility analysis provides an effective way for the seismic risk analysis and evaluation of earth-rockfill dams due to the dam performance with different degrees of damage under earthquakes. Considering the uncertainties of earth-rockfill dam material parameters and ground motion effect, a seismic fragility analysis method for earth-rockfill dams is proposed. Seismic response analysis is undertaken by using different peak accelerations of earthquakes. The combinations of material parameter samples are obtained by means of the method of orthogonal design. A fragility curve of the dam is proposed based on the relative settlement of the dam crest which serves as a seismic damage evaluation index. The seismic fragility analysis is applied in the Yunpeng Core Earth-rockfiU Dam, and the risk probabilities with different seismic damages are obtained. This research is of great significance and applicable value for seismic risk assessment, seismic design, reinforcement and maintenance measures of earth-rockfill dams.