关键词: 边坡稳定性, 可靠度分析, 约束随机场, 有限元, 边坡尺度效应

Abstract:

The simplified method for slope reliability analysis ignores the spatial variability and use same strength parameters during every computation. The probabilistic characterization of soil properties are obtained through discrete sample test; thus can only represent point variability. The stability of slopes is often controlled by the average shear strength within a zone of influence, hence the average properties in the slope domain should be accounted. The unconfined random field ignores the samples’ location information and may lead to higher variability especially when the variability of soil is high. The constraint random field (CRF) is proposed and implemented utilizing random field theory and regionalized variable theory of geostatistics to ensure that the random field realizations match the parameters at the sample locations exactly; and slope reliability analysis is performed by Monte-Carlo random FEM (RFEM) and shear strength reduction technique. The computation results show that the CRF can significantly reduce variance of the random field simulation and get lower probability of failure when the soil variability is high. The comparison of RFEM and simplified method also shows that the simplified method will not always overestimate the probability of failure. The scale effect in slope reliability analysis is highlighted through RFEM; and the applicability of simplified method is discussed.

Key words: slope stability, reliability analysis, constraint random field, finite elements, slope scale effect