基于首次超越概率理论的混凝土坝时变风险率研究

The research of the time-varying risk of concrete dam based on first transcendental probability theory

随着我国大坝安全管理工作逐渐由传统的工程安全管理向工程风险管理方向发展,在役大坝风险水平成为了越来越重要的研究课题.混凝土坝实际运行过程中受到众多随机不确定因素和模糊因素影响,导致大坝自身风险率具有显著的时变特性,本文尝试引入二元高斯算法采用并联体系方法计算混凝土坝系统时变风险率,将时变风险率分析问题转化为静态并联体系失效概率计算问题,通过在广义随机空间内采用JC法计算固定时刻混凝土坝风险率,并基于首次超越概率理论转化为混凝土坝时变风险率.最后,在工程算例分析中以某混凝土重力坝沿坝基抗滑失效为例,通过引入合理的抗力和荷载效应随机过程变量模型,采用该算法对混凝土重力坝抗滑稳定时变风险率进行了分析,验证了该模型的有效性,具有一定的理论和工程应用价值.

With the gradual transition of dam safety management work from engineering safety management to engineering risk management in China,the dam risk degree has become a more and more important research field.Under the influence of mutiple random uncertain and fuzzy factors,the dam risk degree exhibits strong time-varying characteristics.This paper adopted the bivariate Gaussian method to compute the time-varying risk degree based on parallel-system method by transforming the time-varying risk computation into the risk computation of the failure of static parallel system.By computing the static dam risk degree at fixed times based on the JC method in generalized random space,the time-varying risk degrees were obtained based on first transcendental probability theory.Finally,the case study took a certain concrete gravity dam on the foundation interface as an example and the time-varying risk degree of the dam sliding failure was computed with the proposed method by introducing feasible random-process variable model of the resistance and load effects,verifying the effectiveness of the model,which is of certain theoretical and practical values.