复杂工况下高速公路路堑边坡稳定性分析

Stability Analysis of Cutting Slope of Expressway Under Complex Working Conditions

以某高速公路路堑边坡为研究对象,采用大型有限元软件进行了建模分析,分析了坡顶荷载、降雨和坡顶渗漏工况下的边坡安全系数变化规律,并重点研究分析最不利条件下路堑边坡的安全系数和位移变化规律,得到以下结论:边坡安全系数随坡顶荷载、降雨历时和坡顶渗漏历时的增大而减小,相比于坡顶无荷载时,荷载取200kPa、400kPa和600kPa时边坡稳定系数分别减小了43.4%、65.2%和71.8%,在坡顶荷载取最大值600kPa时,边坡安全系数为1.41,仍处于稳定状态;相比于降雨历时为0时,降雨历时取3h、6h、12h和24h时边坡稳定系数分别减小了54.4%、55.4%、56.2%和57.2%;相比于坡顶渗漏历时为0时,坡顶渗漏历时取1d、3d、7d和24d时边坡稳定系数分别减小了0、24.8%、31.2%和44.2%;复杂工况下,坡肩处、平台和二级边坡坡脚处水平位移较大,一级边坡水平位移接近于0,当历时12h时,边坡处于欠稳定状态,当历时达到24h时,边坡稳定系数小于1,此时边坡极可能会发生滑塌,应提前给予加固处置。

Taking the cutting slope of an expressway as the research object,the modeling analysis is carried out by using large-scale finite element software,the variation law of slope safety factor under the working conditions of slope top load,rainfall and slope top leakage is analyzed,and the variation law of safety factor and displacement of cutting slope under the most unfavorable condition is emphatically studied and analyzed.The following conclusions are obtained:the slope safety factor decreases with the increase of slope top load,rainfall duration and slope top leakage duration.Compared with no load on the slope top,the slope stability coefficient decreases by 43.4%,65.2%and 71.8%respectively when the load is 200kPa,400kPa and 600kPa.When the maximum load on the slope top is 600kPa,the slope safety coefficient is 1.41,which is still in a stable state;compared with rainfall duration of 0,when the rainfall duration is 3h,6h,12h and 24h,the slope stability coefficient decreases by 54.4%,55.4%,56.2%and 57.2%respectively;compared with slope top leakage duration of 0,when the slope top leakage duration is 1d,3d,7d and 24d,the slope stability coefficient decreases by 0,24.8%,31.2%and 44.2%respectively;under complex working conditions,the horizontal displacement of slope shoulder,platform and toe of secondary slope is large,and the horizontal displacement of primary slope is close to 0.When the duration is 12h,the slope is in an unstable state,and when the duration is 24h,the slope stability coefficient is less than 1.At this time,the slope is likely to collapse,which should be treated with reinforcement in advance.