基于指数型的浅层滑坡非积水降雨入渗模型研究

Exponential Model of Rainfall Infiltration of Shallow Landslides for Non-ponding Conditions

降雨诱发浅层滑坡稳定性评价的前提是计算边坡的湿润锋深度,目前较为常用的计算方法是基于改进的Mein-Larson降雨入渗模型,但该模型假定斜坡土体初始含水率均匀分布,实际上斜坡土体初始含水率分布是不均匀的,其表现出越靠近地下水位土体含水率越高的规律。为了体现这一实际情况,提出一种指数型的土体初始含水率分布函数,对传统的非积水降雨入渗模型进行了改进,并通过有限元数值分析对土体初始含水率分布函数和改进的模型进行了验证。结果表明:模型计算解与数值解较为接近,说明改进的非积水降雨入渗模型具有一定的适用性。

The calculation of wetting front is the premise of stability evaluation for shallow landslides in- duced by rainfall,and the prevalent computing methods by far based on the improved Mein-Larson model for rainfall infiltration. The model assumes that the water content of the slope soil is constant in the con- duction zone. However,it is actually uneven and becomes higher as the depth gradually approaches to the water table. To reflect the actual situation,this paper proposes an exponential distribution function of initial water content,which improves the traditional model of rainfall infiltration for non ponding conditions. The paper also verifies the function and the improved model by the numerical analysis of finite elements. The results indicate that the calculation solutions are close to the numerical solutions,and thus proves the applicability of the improved model.