考虑土层边界不确定性的边坡稳定性概率分析

目前,边坡稳定性的概率分析多数只考虑了单层土质边坡中的土体参数空间变异性,而忽略了多层土质边坡中土层边界不确定的影响。为此,提出了同时考虑这两类因素的边坡概率分析方法,利用随机有限元法和克里金插值方法同时表征了土体参数空间变异性和土层边界不确定性并考虑了静力触探测试对土层边界不确定性的约束。以某二维边坡为例,对比分析了仅考虑土体参数空间变异性和同时考虑两类因素的情况。结果表明,土层边界不确定性的影响在边坡稳定性分析中不可忽视。详细分析了边界深度变异系数、边界深度相关长度、静力触探布置密度对边坡稳定性的具体影响,并指出静力触探布置的合理密度与边界深度相关长度息息相关。因此,在设计边坡时能否获取边界深度相关长度的信息,是优化设计费用的关键。

Soil layer boundary uncertainty-considered probabilistic analysis on slope stability

At present，most probabilistic analyses of slope stability only consider the spatial variabilities of the parameters of the soil mass in single layered soil slope，while the impact of the uncertainty of the soil layer boundary of multi-layered soil slope is ignored． Therefore，a method of the slope probabilistic analysis under the consideration of both the factors is proposed herein，which simultaneously characterizes the spatial variability of soil mass parameter and the boundary uncertainty of soil layer with the random finite element method and Kriging interpolation method as well as considers the constraint from the static cone penetration test on the boundary uncertainty of soil layer． By taking a two-dimensional soil slope as the study case，the conditions of only considering the spatial variabilities of the parameters of the soil mass and considering both the factors at the same time are comparatively analyzed． The result shows that the impact of the uncertainty of the soil-layer boundary in the slope stability analysis can not be ignored． Furthermore，the specific impacts from the variation coefficient of boundary depth，the correlation length of boundary depth and the density of static cone penetration test on the slope stability are analyzed in detail， while it is pointed out that the reasonable density of the layout of static cone penetration test is closely related to the correlation length of boundary depth，thus whether the information of the correlation length of boundary depth can be obtained or not is the key link for optimizing the design cost．