强降雨条件下考虑饱和渗透系数变异性的基岩型层状边坡可靠度分析

Reliability analysis of bedrock laminar slope stability considering variability of saturated hydraulic conductivity of soil under heavy rainfall

边坡土体因其自身的不均匀性及试验监测的不准确性,饱和渗透系数表现出一定的变异性。为探索强降雨条件下基岩型层状边坡的稳定性及失稳破坏概率,以笔者前期对基岩型层状边坡降雨入渗及其稳定性模型的研究为基础,结合Monte Carlo法,建立了考虑饱和渗透系数变异性的基岩型层状边坡稳定性可靠度计算模型,并基于MATLAB将这一计算过程程序化。最后,利用建立的基岩型层状边坡可靠度计算模型,得到了张家湾滑坡在不同饱和渗透系数变异系数及降雨强度下的失稳破坏概率,分析了饱和渗透系数变异系数及降雨强度对滑坡失稳破坏概率及安全系数均值的影响。计算结果表明在一定降雨条件下,当失稳破坏概率小于50%时,变异系数越大、滑坡发生失稳破坏的概率越大;当失稳破坏概率大于50%时,变异系数越小、滑坡发生失稳破坏的概率越大。

The saturated permeability coefficient of soil is an inherent variable due to its inhomogeneity and the inaccuracy of monitoring. To explore the stability and failure probability of bedrock laminar slope under heavy rainfall, a reliability analysis model of bedrock laminar slope is founded based on the Monte Carlo method and the model for rainfall infiltration and stability analysis developed by the authors, and the variability of saturated permeability coefficient of slope soil is considered in this reliability an.alysis model. To calculate the failure probability, the whole process is realized based on MATLAB. At the same time, the failure probability of Zhangjiawan landslide under different variation coefficients of saturated permeability coefficient and different rainfall intensities is analyzed by using the reliability analysis model, and the influences of variation coefficient of saturated permeability coefficient and rainfall intensity on failure probability and safety factor are analyzed. The results show that the larger the variation coefficient, the greater the failure probability of Zhangjiawan landslide when the failure probability is less than 50%. However, the smaller the variation coefficient, the greater the failure probability of Zhangjiawan landslide when the failure probability is greater than 50%.