各向异性随机场下的边坡可靠度分析  

Slope reliability in anisotropic random fields

作　　者：薛亚东[1,2] 方超[1,2] 葛嘉诚[1,2] 

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092

出　　处：《岩土工程学报》2013年第S2期77-82,共6页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(40772179;41072206)

摘　　要：土性参数的空间变异性表现为明显的各向异性。一般而言,垂直向的变异性要比水平向的大得多。为了体现土性参数在不同方向上变异性的差异,也为了研究这种差异对边坡稳定性的影响,将土性参数模拟为空间各向异性随机场显得更为合理。应用局部平均理论可以有效地离散出二维各向异性随机场,采用强度折减法可以在不预知滑移面的情况下求得边坡安全系数,将以上两种方法与Monte-Carlo法相结合,统计分析Monte-Carlo模拟结果即可得到二维边坡的可靠度。编写了二维边坡可靠度计算的Monte-Carlo随机有限差分程序,并用于计算分析土性参数随机场的各向异性对边坡可靠度的影响,计算结果表明:①随机场的各向异性对边坡可靠度计算结果有较大影响,忽略这一特性将给结果带来不同程度的偏差;②随机场在不同方向的变异性对边坡稳定的影响并不一致,相比于水平方向的变异性,边坡失效概率对垂直方向的变异性更为敏感。It has been recognized that the spatial variability of soil properties exhibit obvious anisotropy. Generally, the mechanical parameters of soils vary more rapidly in vertical direction than in horizontal one. In order to reflect this point of characterization and to study the effect of anisotropic variability on slope stability, it is more rational to simulate soil properties in anisotropic random fields than in isotropic ones. Applying the local average theory can realize the discretization of 2D anisotropic random fields efficiently, and using the shear strength reduction method can obtain the safety factor of slopes without giving a predefined sliding surface. Combining these two methods with Monte-Carlo simulation can easily get slope reliability. So a Monte-Carlo stochastic finite difference method is formed based on the idea, and it is adopted to investigate the effects of anisotropic spatial variability of soil properties on the slope reliability. The numerical results show that the anisotropy of random field has a significant impact on the slope reliability, and ignoring the feature will result in varying deviation. In addition, the vertical variation of soil properties has a more significant influence on the slope stability.

关 键 词：边坡稳定 可靠度 随机场 局部平均法 各向异性 相关距离 

分 类 号：TU43[建筑科学—岩土工程]