论文部分内容阅读
土体饱和渗透系数表现为天然的变异性,为此基于Green-Ampt模型建立了考虑饱和渗透系数变异性的降雨入渗物理模型,并藉此模型确定了坡体湿润锋深度和含水率分布。然后结合无限长非饱和土边坡稳定模型得到解析形式的反映边坡稳定性的极限状态函数。采用Monte Carlo法对饱和渗透系数进行随机抽样并最终建立降雨条件下考虑饱和渗透系数变异性的边坡概率分析框架。针对一假想边坡,探讨了饱和渗透系数的变异系数、降雨持时和降雨强度对边坡破坏概率以及破坏发生时间概率分布的影响,结果表明:在降雨初期,边坡的破坏概率随饱和渗透系数变异性的增强而逐渐增加,但随着降雨的持续,破坏概率开始随变异性的增强而显著降低;滑坡最可能发生时间的大小并不受饱和渗透系数变异性的影响,而是直接取决于降雨强度;滑坡最可能发生时间所对应的概率却随变异性的增强而逐渐减小。
Therefore, the saturated permeability coefficient of soil shows natural variability. Based on the Green-Ampt model, a physical model of rainfall infiltration considering saturated permeability coefficient variability is established, and the depth and moisture distribution of wetting front are determined by this model. Then the limit state function reflecting the slope stability is obtained by combining the stability model of slope with infinitely long unsaturated soil. The Monte Carlo method was used to randomly sample saturated permeability coefficients and finally to establish the slope probability analysis framework considering the variability of saturation permeability under rainfall conditions. For a hypothetical slope, the effect of coefficient of variation of saturated permeability coefficient, rainfall duration and rainfall intensity on the probability of slope failure and the probability distribution of failure time are discussed. The results show that the failure probability of slope with saturation permeation Coefficient of variability increases gradually, but as the rainfall continues, the probability of failure begins to decrease significantly with the increase of variability; the magnitude of the most likely time of landslide is not affected by the variability of saturated permeability coefficient but directly The rainfall intensity; the probability of the most likely time of landslide decreases with the increase of the variability.