基于Bayes方法的堤坝时变渗流风险率评估

随着工程的老化,影响堤坝防洪安全的各种不确定性因素将发生缓慢变化。定量评估各种随机量的时变特性,对确定时变的防洪风险率至关重要。Bayes方法提供了对随机量概率分布进行推断的框架,利用一切可以利用的先验信息,并通过不断的实时采样信息,修正和改进原有的概率分布规律假设,以减少所考察随机量的时变不确定性。本文以渗流随机量的时变特性分析为例,论证了采用Bayes方法对时变随机量进行定量评估的可行性和适用性,并建议以正态共轭分布模拟数据的采样过程并计算其后验分布。在此基础上,讨论了渗流风险率计算的实测法模型,分析了随机变量的时变特性对渗流风险率的影响。

Assessment of seepage time-varying risk rate for embankments and dams based on Bayesian approach

Various stochastic factors have mild time-varying negative impact on the flood control safety due to the ageing of hydraulic projects. It is important that the time-varying characteristics of the various stochastic factors are quantitatively predicted to evaluate the time-varying flood control risk rate. A frame to infer the statistical distributions of the stochastic variables is provided by the Bayesian approach. By using the prior information the results of suitable sampling inspections can be used to modify and improve the hypothesis of accumulated statistical distribution to control the time-varying uncertainty. The time-varying characteristics of seepage variable L were analyzed, the feasibility and suitability by using the Bayesian approach to quantitatively predict the time-varying stochastic characteristics were proved. The inspection procedure simulated by using the Normal conjugate function was suggested, and the posterior distribution of L was computed. On this basis, a practical model for quantitatively predicting the seepage risk rate of the embankments and dams was discussed, and the influence of the time-varying characteristics of the stochastic variable L on seepage risk rate was analyzed.