地铁车站基坑稳定风险值计算

摘要

In order to study the stability value-at-risk calculation of a foundation pit of subway station, the calculation method and process of single-factor risk ratio, factors combination risk ratio and value-at-risk were constructed based on the combination of probability analysis theory in the uncertainty analysis theory and function failure theory. The results show that building a high dimensions mapping model from influencing factor to response value can compute the single-factor risk ratio better based on the numerical methods which combined with the Monte Carlo simulation analysis method. The stability of the foundation pit is controlled by the integral landslide, soil parameters follow the normal distribution, and the manner of excavation and supporting follows the Beta distribution. Through the calculation of factors combination risk ratio and value-at-risk, the degree of probabilistic risk of the foundation pit can be differentiated, and the value-at-risk can be estimated further.%将不确定性分析法中的概率分析方法与失效分析方法相结合,构建单因素风险率、因素组合风险率、风险值的计算方法与步骤,对某车站基坑稳定风险值计算进行研究.研究结果表明:以数值分析方法为基础,建立影响因素与响应值之间的高维映射模型,结合Monte Carlo模拟分析方法,能较好地进行单因素风险率计算；该车站基坑的整体滑动失稳对基坑稳定起控制作用,基坑土层参数变化基本服从正态分布,开挖及支护方式变化基本服从贝塔分布；通过多因素影响下的稳定风险率、风险值的计算,判别了该车站基坑的风险概率等级,估算了相应的风险值.