Bayes约束随机场下坝基溶蚀区随机模拟方法及其影响分析

Stochastic simulation and influence analysis of dissolution dam foundation under Bayes constraint random field

基于完全随机场模拟溶蚀岩体可能会高估其空间变异性和不能有效地利用溶蚀以外的地质信息和实践经验,提出用Bayes约束参数随机场模型描述坝基溶蚀区的随机模拟方法。引入Bayes公式,对溶蚀区域岩土参数的统计特性进行修正,反映出地质勘测的新增地质信息和试验参数信息,建立约束随机场,并在此基础上进行随机有限元分析,研究坝基溶蚀对大坝结构性态的作用效应。计算结果表明,相对于完全随机场模型,Bayes约束随机场模型更为客观地考虑了溶蚀岩体的空间变异性,有效地降低了溶蚀参数完全随机场下结构响应的模拟方差。在概率分析过程中,推荐蒙特卡洛响应面耦合方法(MC-RSM)作为适用于复杂工程的随机模拟方法,该方法能够代替直接MC法对同样力学机制的不断重复,减小计算时间成本。

The unconfined random field may lead to higher variability especially when the variability of dissolution foundation is high, and may lose the geological information and practice experience. So the Bayes constraint random field model is put forward. The constraint random field is built by introducing Bayes formula to modify the distribution characteristics of parameters of dissolution, to reflect the new geological and samples＇ location information. Then the effect of the dissolution system in the dam foundation is studied through stochastic finite dement method （SFEM）. The results show that the space variability of dissolution can be considered more objectively by Bayes constraint random field model rather than the unconfined one; also, the variance of the structural responses can be reduced effectively. In the probability analysis process, the Monte Carlo response surface coupled method （MC-RSM） is recommended for the random simulation of complex engineering, which can reduce the simulation time relative to the direct Monte Carlo method which can only repeat the process of the same mechanical mechanism.