中文摘要：

降雨是诱发滑坡的最主要因素之一,降雨入渗将显著降低非饱和土的基质吸力,从而降低边坡土体抗滑力。本文提出了考虑降雨入渗的多层非饱和土边坡稳定性分析方法。首先改进Green-Ampt入渗模型,提出适合多层非饱和土边坡降雨入渗的计算方法;然后得到各层土体在入渗各阶段的强度参数值;最后,采用强度折减法计算整个边坡在入渗条件下的安全系数。将本方法应用于广州大夫山滑坡案例发现滑动面和实际情况接近,为短期强降雨诱发的浅层滑坡。分析了不同降雨强度和历时对滑坡稳定性的影响,结果表明：降雨入渗导致边坡潜在最危险滑面的位置主要在浸润锋处或土体与基岩交界处。低强度长历时的降雨过程中,雨水入渗深度较大,易发生深层滑动;在高强度短历时的降雨过程中,雨水入渗深度较小,更易发生浅层滑动;随着降雨强度和降雨时间的增加,入渗深度增加,进而降低边坡的稳定性。

英文摘要：

Rainfall is one of the major causes for slope failures. Rainfall infiltration reduces the slope resis-tance by largely lowering the matrix suction. The paper presents a method slope stability analysis ofmulti-layered unsaturated soils. Firstly,the Green-Ampt infiltration model is improved to calculate the infil-tration depth in multi-layered unsaturated soils. Then, the soil strength parameters are estimated with con-sideration of rain infiltration. Finally, stability analysis is conducted by using of strength reduction methodwith ABAQUS. The method is applied to the case study of the Dafushan landslide in Guanzhou and foundthat the shallow slip surface in the simulation is close to the real case. Slope stability analyses are furtherconducted with different rainfall intensity and lasting period. It is found from the analysis that the slide sur-face is most probably located in wetting front or at the interface between the soils and bedrock. The longterm and low density antecedent rainfall makes larger infiltration depth and deep seated slope failure;theshort term and high density antecedent rainfall usually cause smaller infiltration depth and shallow seatedslope failure;with the increase of rainfall intensity, rainfall duration, the infiltration depth increases, andthen aggravate the slope failure.