考虑参数空间变异性边坡可靠度分析的Kriging方法

Reliability analysis of slope stability considering spatially varying soil properties using Kriging method

提出了考虑土体参数空间变异性边坡可靠度分析的Kriging方法.采用拉丁超立方抽样方法产生样本点,通过Karhunen-Loève(KL)级数展开方法离散土体抗剪强度参数相关对数随机场.基于有限元滑面应力法计算边坡安全系数,利用Kriging模型的优良特性拟合边坡可靠度分析的功能函数,在此基础上采用蒙特卡洛方法计算边坡失效概率,并编写了计算程序.最后研究了该方法在2个边坡可靠度分析中的应用.结果表明:与其他方法相比,该方法在考虑土体参数空间变异性的边坡可靠度分析中不仅计算效率高,而且精度也较好,为解决复杂边坡可靠度问题提供了一种新的有效的分析工具.忽略土体参数空间变异性并不一定会导致对边坡可靠度的保守估计,同时应准确地估计抗剪强度间的互相关性.

A new method is proposed for reliability analysis of slope stability considering spatial variability of soil parameters based on the Kriging model.The Latin hypercube sampling method is employed to generate sampling points.The Karhunen-Loève（KL） expansion method is used to discretize correlated lognormal random fields of shear strength parameters.The factor of safety is calculated using the finite element method.The proposed method can well fit the actual performance function for slope reliability analysis using a Kriging model,which has an excellent modeling capability.The probability of slope failure is then estimated using Mote Carlo simulation based on the Kriging model.A computer program is developed.Two illustrative examples of reliability analysis of soil slope stability are investigated to demonstrate the validity of the proposed method.The results indicate that the proposed method can effectively evaluate the reliability of slope stability considering spatially varying soil parameters.Compared with other methods,this method can provide one effective way for solving complex slope reliability problems.Ignoring the spatial variability of soil properties would not always lead to conservative estimation of slope reliability.In addition,the cross-correlation between the cohesion and friction angle should be accurately estimated.