降雨循环条件下高切坡稳定性演化过程及预测方法

为进一步揭示降雨循环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，以乐西高速马边至昭觉段某粉质黏土覆盖层基岩型台阶状高切坡为研究对象，通过室内干湿循环试验建立土体抗剪强度参数劣化数学模型；利用Geo-studio数值模拟软件研究多工况降雨循环下高切坡降雨入渗过程，揭示不同降雨循环工况下及雨后高切坡内部渗流场及稳定性变化规律，建立降雨型高切坡稳定系数逐年劣化方程；结合室内试验及数值模拟结果，建立该类高切坡稳定系数预测方法。研究结果表明：降雨入渗过程中高切坡潜在滑移面形状及位置并不发生明显变化，且表现为高切坡深处圆弧面及基岩积水面的组合型滑面；相同降雨时间内，高切坡降雨入渗深度及稳定性劣化幅度与降雨强度成正相关；单次降雨循环周期内，高切坡稳定性劣化幅度与降雨循环次数成负相关；高切坡降雨入渗深度或入渗总量越大，雨后高切坡稳定系数回升越小；高切坡稳定系数劣化系数采用土体抗剪强度参数劣化系数平均值较为安全合理，所建降雨型高切坡稳定系数预测方法具有较高的精度。

Analysis of the stability evolution process and prediction method of high cutting slope under rainfall cycle condition

In order to further reveal the process of rainfall infiltration and stability evolution of bedrock-type stepped high cutting slopes under rainfall cycling conditions, taking the bedrock-type stepped high cutting slope of a silty clay cover layer from Mabian to Zhaojue section of Lexi Expressway as the research object, a mathematical model for the deterioration of soil shear strength parameters was established through indoor dry-wet cycle tests; Geo-studio numerical simulation software was used to study the rainfall infiltration process of the high cutting slope under multi-case rainfall cycles, which reveals the internal seepage field and stability change rules of high cutting slopes under different rainfall cycle conditions and after rain. And the annual degradation equation of the stability coefficient of the rainfall-type high cutting slope has been established; Combining the results of indoor experiment and numerical simulation, a method for predicting the stability coefficient of this type of high cutting slope has been established. The research results show that the shape and position of the potential sliding surface of the high cutting slope does not change significantly during the process of rainfall infiltration, and it appears as a combined sliding surface of the circular surface and the bedrock water surface at the depth of the high cutting slope; In the same rainfall period, the depth of rainfall infiltration and the extent of stability degradation of high cutting slopes are positively correlated with rainfall intensity; The degree of stability degradation of high cutting slopes in a single rainfall cycle is negatively correlated with the number of rainfall cycles. The greater the depth of rainfall infiltration or the total rainfall infiltration of high cutting slopes, the smaller the recovery of the stability coefficient of high cutting slopes after rain; It is relatively safe and reasonable to use the average value of the degradation coefficient of the shear strength parameter of the soil for the degradation coefficient of the high cutting slope stability coefficient. And the prediction method for the stability coefficient of rainfall-type high cutting slope has high accuracy.