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建立了分析在非平稳地震动过程中重力坝失效路径可靠度的计算方法。首先,说明了指定的失效路径的失效概率与失效路径上的单元的失效概率的关系。其次,使用了虚拟变量代换了所需求得未知变量,简化了使用一次二阶矩法求解梯度的过程。然后,使用了虚拟激励法计算了响应位移的方差,并推导了单元第一主应力的均值与方差的求解公式,从而为上一步的计算提供了参数。最后,提出了一种搜索可靠度最小的失效路径的算法。计算结果表明,该文的方法收敛速度较快,具有很好的实用性。
A method to calculate the reliability of failure path of gravity dam during non-stationary ground motion is established. First, the relationship between the failure probability of the designated failure path and the failure probability of the unit on the failure path is described. Secondly, using the dummy variable to replace the unknown variable, it simplifies the process of solving the gradient using the first-order second moment method. Then, using the virtual excitation method, the variance of the response displacement is calculated and the formula of the mean and variance of the first principal stress of the unit is deduced, which provides the parameters for the previous calculation. Finally, an algorithm to search for the failure path with the lowest reliability is proposed. The calculation results show that the method of the paper converges fast and has good practicability.