基于响应面法和Morgenstern-Price法土坡可靠度计算方法

基于响应面法,建立了一种高效的边坡可靠度指标和失效概率近似计算方法。该法在构造响应面函数时,抽样点计算采用Morgenstern-Price法取代传统费时的有限单元法,大大降低了计算工作量。利用Monte-Carlo随机抽样原理,提出了一种能同时确定边坡最危险非圆弧滑动面和最小可靠度指标的随机搜索新算法。该文给出的两个算例验证了方法的实用性和可靠性,其计算结果同时表明:当分别以最小可靠度指标和最小中值安全系数为目标函数时,搜索到的边坡最危险滑动面相差较大。最后,探讨了土性指标(c,φ)的分布概型及相关性对边坡可靠度计算结果的影响。

CALCULATION METHOD OF EARTH SLOPE RELIABILITY BASED ON RESPONSE SURFACE METHOD AND MORGENSTERN-PRICE PROCEDURE

Based on response surface method (RSM), a highly efficient approximate method for computing the reliability index or failure probability of slopes is proposed. The Morgenstern-Price method is adopted to compute sample points instead of traditional time-consuming finite element method in the construction of response surface functions, and the computing time is greatly decreased. By making use of the random sampling idea of Monte Carlo technique, a new random search algorithm is presented, which can locate the critical non-circular slip surface associated with the minimum reliability index. Two examples are given to verify the practicability and reliability. It is also found that when separately taking the minimum safety factor and minimum reliability index as the target function their critical slip surfaces show significant difference. In the end, the influence of the probability distribution and correlativity of soil parameters on the reliability index of slope is discussed.