基于极限平衡法的边坡稳定性可靠度分析

传统方法对边坡稳定性进行分析时,不能定量考虑土体参数随机性、变异性的影响。为更好地对边坡稳定性进行评价,本文基于传统边坡稳定性计算方法,同时考虑参数的变异性和分布类型的差异,利用蒙特卡洛模拟技术,编制了相应程序。针对某匀质边坡,利用Fellenius法、Bishop法、Janbu法和Morgenstern-Price法进行破坏概率计算。结果表明,安全系数大于1时,边坡仍有破坏的可能,边坡稳定性对参数变异性的敏感度不同,参数变量分布类型也会对边坡稳定性评价结果产生影响。利用可靠度方法得到的可靠度指标、破坏概率等指标,能够定量地描述各参数变异性对边坡稳定性的影响。因此,可以将可靠度的方法和确定性的方法相结合,对边坡的稳定性进行描述,为滑坡风险的评估提供参考依据。

Slope Stability Reliability Analysis Based on Limit Equilibrium Methods

The traditional methods of evaluating the slope stability can’t consider quantitatively the influence of soil parameter randomness and variability. To better evaluate the slope stability, the limit equilibrium analysis method based on Monte-Carlo simulation, considering the variability and probability distribution of parameters, is programed to evaluate the reliability of the slope stability. In view of a homogeneous slope, the Fellenius method, Bishop method, Janbu method and Morgenstern-Price method based on Monte-Carlo simulation are chosen to calculate the failure probability. Calculation results show that there is still the possibility of damage when the slope safety factor is greater than 1, and the parameter variation, parameter variables distribution will also be a certain influence on slope stability evaluation results. Reliability index and failure probability index can be used to describe quantitatively the effects of parameter variation on the slope stability.Therefore, the results of reliability methods and deterministic methods can be together used to describe the slope stability , and can be provided as the reference for landslide risk assessment.