中文摘要：

针对热带与亚热带地区由于降雨引起的边坡失稳，采用数值模拟方法，基于Mein-Larson降雨入渗模型，提出了均质无限长非饱和土边坡在均匀降雨强度下，由于基质吸力的变化，导致土体强度指标的变化，从而发生边坡破坏的条件。结论表明，在降雨强度大于土壤的饱和渗透系数并且降雨持时满足一定的时间下，降雨才可能土坡失稳。

英文摘要：

In view of the slope instability due to rainfall in tropical and subtropical regions, the paper proposes a simple model to estimate slope stability under rain infiltration. In this paper, numerical simulation method is adopted. Based on Mein-Larson rain infiltration model, the essential conditions to homogeneous and infinite slope failure in unsaturated soils under uniform rainfall intensity are proposed. The change of matric sunction lead to the intensity index of soil changing, therefore resulting in slope slides. The research results show that if rain intensity surpasses the saturated coefficient of permeability of soil and the prolonged period of rainfall satisfies an essential time,the rain infiltration will lead to instability.