考虑抗力退化的混凝土坝时变可靠性分析方法

Time-dependent Reliability Analysis Method for Deteriorating Concrete Dams

混凝土坝服役期间,由于具有随机时变性,结构抗力性能随时间发生不确定性退化,因此有必要从时变可靠度角度评估其运行安全性能。在概率密度演化理论(PDEM)的框架内,提出一种基于PDEM的时变可靠性分析方法(EP-TSR),即利用演化过程建立坝体结构时变响应的概率密度演化方程,引进虚拟随机过程技术再次建立概率密度演化方程并求解得到随机性初始条件,最终得到坝体静态响应的概率密度曲线演化规律和丰富的时变概率统计信息,并将该方法与Monte Carlo方法计算得到的结果进行对比。结果表明,EP-TSR法应用于混凝土坝有效、合理,且具有更高的计算精度和效率。

Due to the random time-dependent characteristics of concrete dams during service life,its structural resistance performance degrades in an uncertain manner.Therefore,it is necessary to evaluate its safety performance from the perspective of time-dependent reliability.In the framework of probability density evolution theory(PDEM),a time-dependent reliability analysis method based on PDEM was proposed.The probability density evolution equation for the dam time-dependent response was established through the evolutionary process.Another probability density evolution equation was established by introducing virtual random process technology to solve the initial condition with randomness.Finally,the probability density curve evolution law of the dam's static response and rich time-dependent probability statistical information were obtained.The method was compared with the results calculated by the Monte Carlo method.The results show that the EP-TSR method is effective and reasonable for concrete dams,and has higher computational accuracy and efficiency.