含优势渗流层边坡降雨入渗下的可靠度分析

含优势渗流层边坡在降雨入渗的作用下其渗流场往往具有较高的不确定性，这给边坡的稳定性评价带来困难，通常采用概率的方法解决此类问题。针对含优势渗流层边坡降雨入渗下的可靠度问题，通过将应力分析中的点估计-有限元法引入到边坡渗流-稳定性分析，提出了考虑优势渗流层渗透特性不确定性的渗流概率分析和边坡可靠度分析方法；其次以广西某含碎石夹层土坡为例，分析了降雨入渗下碎石夹层的优势渗流效应及渗流概率，并基于此开展了该边坡降雨入渗下的可靠度分析。结果表明:①含优势渗流层边坡雨水沿优势渗流层渗入坡体内部的深度显著高于沿坡面渗入的深度；优势渗流层渗透特性的不确定性对渗流结果的影响较大，使得边坡稳定性分析具有较强的不确定性；②随着雨水入渗持时的增加，含优势渗流层边坡不同滑动面的失效概率总体呈现增加趋势，最危险滑动面的位置不断向边坡下部演化；依托工程滑动面位置的预测结果与工程实际吻合；③提出的概率分析方法适用于分析含优势渗流层边坡降雨入渗影响下的稳定性问题，而且具有计算量小的优势，可作这类边坡可靠度分析的一种新方法。 

Reliability analysis of slope with dominant seepage interlayer under rainfall infiltration

Slopes with dominant seepage interlayers (DSI)often have relatively high uncertainty in their seepage field under the action of rainfall infiltration, which brings difficulties to the stability evaluation.In this regard, probabilistic methods are usually used to analyze the stability of such slopes.For analyzing the reliability of slopes with DSI under rainfall infiltration, the point estimation-finite element method used in the stress analysis was introduced to the slope seepage-stability analysis, and a method for seepage probability and reliability analysis of slopes was developed considering the uncertainty of permeability of DSI.Then, by taking a soil slope with gravel interlayer acting as DSI in Guangxi Province as the engineering case, the seepage probability of DSI under rainfall infiltration was analyzed, and then the slope reliability analysis was conducted based on the seepage probability.Results show that:① In the slope with DSI, the depth of rainwater infiltration along DSI is significantly higher than that along the slope surface; the uncertainty of the permeability of DSI has a great impact on the seepage field, which results in the strong uncertainty of slope stability; ② With the rainwater infiltration in the slope with DSI, the failure probability of different potential slip surfaces generally increases, and the position of the most dangerous slip surface evolves from the upper part to the lower part of the slope. The prediction of the position of slip surface is consistent with the practice; ③The proposed probability analysis method, with the advantages of small calculation amount, is suitable and can be used as a new method for analyzing the stability of slopes with DSI under the influence of rainfall infiltration.