基于Chen-Young模型及不平衡推力法的降雨型高切坡稳定性演化过程分析

Stability Evolution Process of Rainfall-Type High-Cut Slope Based on Chen-Young Model and Unbalanced Thrust Method

为进一步揭示降雨条件下基岩型台阶状高切坡的降雨入渗及稳定性演化过程,基于Chen-Young模型及不平衡推力法建立了基岩型台阶状高切坡概念模型,推导了该类降雨型高切坡稳定性计算方法;利用Geo-studio数值模拟软件开展了多工况下高切坡降雨入渗过程研究,揭示了不同降雨工况下及雨后高切坡内部渗流场及稳定性变化规律;获得了该类边坡在不同降雨时间及降雨强度作用后的稳定性变化情况,基于此给出了该类高切坡在不同降雨量及降雨时间下的稳定性预测方法。研究结果表明:与倾斜式边坡不同,该类边坡降雨入渗过程应考虑高切坡尺寸效应,依据降雨入渗深度与边坡形状尺寸大小关系,可将该类边坡入渗过程划分为3种模式,其中强降雨条件下该类边坡潜在滑面为湿润锋面及基岩面的双折线型滑面,且模拟结果与模型计算具有较好一致性;降雨条件下高切坡稳定性劣化过程可划分为平稳阶段、快速劣化阶段、缓慢劣化阶段及回升阶段4个阶段;高切坡稳定性状态与降雨时间、降雨强度成负相关,降雨总量一致时,与降雨强度相比,降雨时间影响边坡稳定性较剧烈;降雨入渗深度及总量越大,高切坡雨后稳定系数回升幅度越小。

In order to further reveal the process of rainfall infiltration and stability evolution of bedrock stepped high-cut slope under rainfall conditions, a conceptual model of bedrock stepped high-cut slope was established based on the Chen-Young model and unbalanced thrust method, and the stability calculation method of this type of high-cut slope under rainfall conditions was deduced. Geo-studio numerical simulation software was used to study the rainfall infiltration process of the high-cut slope under multiple conditions, and the internal seepage field and stability variation laws of the high-cut slope under different rainfall conditions and after rain were revealed. The stability changes of this type of slope under different rainfall time and rainfall intensity were obtained, and the stability prediction method of this type of high-cut slope under different rainfall volume and rainfall time was given. The research results show that: different from the inclined slope, the size effect of high-cut slope should be considered in the rainfall infiltration process of this type of slope. According to the relationship between rainfall infiltration depth and slope shape and size, the infiltration process of this kind of slope can be divided into three modes, in which the potential sliding surface of this type of slope under the condition of heavy rainfall is a double-folded sliding surface of wet front and bedrock surface, and the simulation results are in good agreement with the model calculations. The degradation process of stability of the high-cut slope under rainfall conditions can be divided into four stages: stationary stage, rapid degradation stage, slow degradation stage, and recovery stage. The stability of high-cut slope is negatively correlated with rainfall time and rainfall intensity. When the total rainfall is consistent, the rainfall time affects the slope stability more severely than the rainfall intensity does. The greater the rainfall infiltration depth and the total rainfall amount, the smaller the recovery amplitude of the stability coefficient of the high-cut slope after rain.