摘要
心墙堆石坝地震破坏是渐变的过程,目前地震易损性研究均采用确定性的破坏准则;然而由于对破坏等级认知的局限性,导致地震破坏等级的划分具有模糊性。针对上述问题,本文提出考虑破坏准则模糊性的心墙堆石坝地震易损性分析方法。首先,采用模糊集理论将大坝破坏等级界限值模糊化,并提出能够反映隶属度函数形式和模糊区间大小的模糊度系数来量化地震模糊破坏等级;其次,依据地震模糊破坏等级推导地震易损性函数模糊-概率积分计算公式,弥补目前地震易损性函数计算公式依据确定性破坏准则的不足,并结合概率地震需求模型,获得破坏准则模糊条件下的大坝地震易损性曲线,得到坝体结构在不同地震强度作用下产生各个等级破坏的概率。将所提方法应用于糯扎渡心墙堆石坝地震易损性分析中,结果表明:考虑破坏准则模糊性获得的地震易损性曲线与传统易损性曲线趋势一致;在破坏准则模糊性条件下,相同坝顶震陷率对于发生高等级破坏的隶属度增加,导致在一定的地震动强度下,坝体发生高等级破坏的概率有所增加;此外,模糊度系数越大,破坏准则模糊性对地震易损性的影响越大。
The earthquake failure of core rockfill dams is a gradual process,but deterministic failure criteria were adopted in its previous seismic vulnerability studies,and the classification of its grades is ambiguous due to limited understanding of its mechanism and grades.This paper describes a seismic vulnerability analysis method for core rockfill dams,considering the fuzziness of failure criteria.First,the fuzzy set theory is used to fuzzily the threshold values of dam damage levels;and to quantify the seismic fuzzy damage levels,we formulate a fuzziness coefficient that reflects the membership function form and the size of the fuzzy interval.Then,a fuzzy-probability integral formula for calculating the seismic vulnerability function is derived from the fuzzy seismic damage level.For the calculation,this formula makes up for the deficiency of its existing formula that is based on the deterministic failure criterion.Combined with the probabilistic seismic demand model,this new formula gives a dam seismic vulnerability curve under the fuzzy failure criterion and predicts the probability of dam structure failure at different levels corresponding to different earthquake intensities.Our method is applied to the seismic vulnerability analysis of a core rockfill dam in Southwest China.Results show that the seismic fragility curve obtained using the fuzzy failure criterion follows a trend similar to the traditional curve.Under the fuzzy criterion,the subsidence rate of the dam crest increases the membership degree for high-level damage,resulting in an increase in the probability of high-grade dam body failure under the same earthquake intensity.And a greater ambiguity coefficient means a greater impact of the failure criterion ambiguity on seismic vulnerability.
作者
李星辰
苏哲
黄青富
杨旸
王晓玲
余佳
LI Xingchen;SU Zhe;HUANG Qingfu;YANG Yang;WANG Xiaoling;YU Jia(State Key Laboratory of Hydraulic Engineering Simulation and Safety,Tianjin University,Tianjin 300072,China;Kunming Engineering Corporation Limited of PowerChina,Kunming 650051,China)
出处
《水力发电学报》
CSCD
北大核心
2022年第11期107-116,共10页
Journal of Hydroelectric Engineering
基金
天津市自然科学基金(19JCYBJ22600)。
关键词
心墙堆石坝
地震易损性
破坏准则
模糊不确定性
模糊-概率积分
core rockfill dam
seismic vulnerability
failure criterion
fuzzy uncertainty
fuzzy-probability integral
