初始含水率非均匀分布的无限边坡稳定性计算模型研究

Research on infinite slope stability calculation model with non-uniform distribution of initial water content

降雨入渗模型与边坡稳定性分析相结合是分析降雨诱发浅层滑坡的有效方法。文章考虑初始含水率非均匀分布对稳定性的影响,结合已有文献提出一个初始含水率呈线性分布的无限边坡稳定性简化计算模型,并运用Mein-Larson入渗模型及数值模拟方法验证该模型的可行性和计算精度;讨论同一土质和坡度条件下,降雨强度p、含水率线性变化率k以及地表初始含水率θ0对模型计算精度的影响。结果表明:简化模型能够较为准确地描述恒定降雨入渗过程,并且适用于降雨强度大于土壤入渗能力时的无限边坡稳定性分析计算;采用简化模型进行稳定性计算,p相同时,k值的变化对入渗深度Z w的计算精度影响较为显著,而对安全系数F s计算精度的影响总体上不明显;对于给定土质和坡度的无限边坡,当θ0值取0.15、k值取0.07时,采用该模型计算Z w的精度最高;与严格的数值模拟方法相比,该文提出的简化模型公式较为简单、计算用时较少,计算效率得以提高。研究结果为降雨型滑坡的稳定性分析提供了借鉴和参考。

The rainfall infiltration model in combination with slope stability analysis is an effective approach to analyze rainfall-induced shallow landslides.This paper considered the influence of non-uniform distribution of initial water content on stability,proposed a simplified calculation model of infinite slope stability with linear distribution of initial water content based on the existing literature,and verified the feasibility and calculation accuracy of the model by using Mein-Larson infiltration model and numerical simulation method.The paper discussed the influence of rainfall intensity p,linear rate of change of water content k,and initial surface water contentθ0 on the calculation accuracy of the model under the same soil and slope conditions.The results show that the simplified model can describe the infiltration process of constant rainfall more accurately and is suitable for the stability analysis of infinite slopes when the rainfall intensity is greater than the infiltration capacity of soil;when the simplified model is used for stability calculation,the change of k value has a significant influence on the calculation accuracy of infiltration depth Z w when p is the same,while the influence on the calculation accuracy of factor of safety F s is generally insignificant;for an infinite slope with a given soil texture and slope angle,when the value ofθ0 is 0.15 and the value of k is 0.07,the accuracy of Z w calculated by this model is the highest;compared with strict numerical simulation method,the formula of the simplified model proposed in this paper is simpler and takes less time to calculate,which improves the calculation efficiency to a certain extent.The results provide reference for the stability analysis of rainfall-type landslides.