地震工况下兰州南绕城高速公路路堑高边坡格构支护效果评价

Evaluation on the lattice support performance for the high cutting slope along Lanzhou South Ring Expressway under the earthquake condition

摘要:

以兰州南绕城高速公路已加固典型路堑高边坡为研究对象，利用AutoCAD及ANSYS软件建立所选典型边坡的三维数值模型，在此基础上运用有限差分软件FLAC3D对其在地震工况下的稳定性进行科学评价，目的是为黄土类高边坡工程防护及安全设计提供参考。得出的结论为：当水平向地震加速度为0.1g和0.2g时边坡处于稳定状态，水平向地震加速度为0.3g时边坡处于基本稳定状态，水平向地震加速度为0.4g时边坡处于不稳定状态。研究表明，格构锚杆支护承受了大量拉张应力及剪应变增量等，效果显著，对边坡稳定性发挥了重要作用。因该公路建设区抗震设防烈度为8度，地震加速度设计为0.2g，所以地震工况下的所选格构支护边坡处于稳定（稳定系数为1.15）状态，能够满足规范要求。

Abstract:

Taking the reinforced typical high cutting slope along Lanzhou South Ring Expressway as the research object, a three-dimensional numerical model is established for the selected typical slope by using AutoCAD and ANSYS software. On this basis, the finite differential software FLAC3D is used to evaluate the stability of the slope under the earthquake condition, so as to provide reference for the protection and safety design of loess-like high slope works. It is concluded that the slope is stable when the horizontal earthquake acceleration is 0.1g and 0.2g; the slope is basically stable when the horizontal earthquake acceleration is 0.3g; and the slope is unstable when the horizontal earthquake acceleration is 0.4g. The lattice bolt support bears large part of the tensile stress and shear strain increment, et al., with remarkable effect, and it plays an important role in slope stability. The specified seismic intensity for the highway construction region is 8 degrees with the designed seismic acceleration of 0.2g; thus, the selected lattice-supported slope is in a stable state (the stability coefficient is 1.15) under earthquake conditions, which can meet the specification.