基于概率方法的土质边坡稳定性分析

Stability Analysis of Soil Slope based on Probabilistic Method

以某公路路堑边坡为例,设计了强度参数最小值组合、最大值组合、平均值组合的边坡确定性方法的计算方案,用其检验了概率方法的合理性,分析了两者的异同。设计了Monte-Carlo循环次数为5000,10000,100000,1000000和5000000等5种计算工况。发现随着循环次数的增加,安全系数的分布范围逼近最小值组合及最大值组合情况下确定值方法计算的安全系数值;安全系数的平均值与平均值组合时,确定性方法计算的结果差别不大;失效概率随循环次数的增加没有稳定趋势,可靠性指数、安全系数则逐步趋稳。

A soil cut slope of highway is studied under conditions of minimum, maximum and average combinations of soil strength parameters by means of deterministic method of slope stability. The result is used to test the reasonability of probabilistic method and the difference between these two kinds of method. Simultaneously, the influence of Monte - Carlo cyclic times is studied under condition of 5 000, 10 000,100 000, 1 000 000 and 5 000 000 cyclic times. It is found that the distributing scope of safety factor is approaching that of deterministic method under conditions of minimum and maximum combinations of soilstrength parameters step by step, that the difference between the average bf safety factor and the result of deterministic method under condition of average combination of soil strength parameters is very small, that with the increasing of cyclic times, the failure probability doesn ＂t appear stable, but the reliability index and factor of safety respectively reaches a stable value.