黄土高边坡开挖过程中的稳定性分析

Stability Analysis of High Loess Slope in Excavation Process

根据甘肃兰州南坡坪—恩寺段K0+400~K1+498黄土高边坡地质地形特征,运用有限元软件对边坡支护和未支护工况进行数值模拟,对比分析两种工况下边坡的变形形态,塑性区的分布以及边坡稳定性。分析结果表明:未支护开挖和及时支护开挖各级测点的水平位移增量值变化趋势基本一致,产生的水平位移均指向坡外,坡面中部水平位移最大,坡顶水平位移最小;在竖向变形中,支护和未支护两种工况都表现出高测点比低测点变形大,最大竖向变形出现在坡顶,每级开挖都出现卸载回弹现象。综上说明,支护措施可有效减少水平和竖向变形,维持坡体稳定。

According to the geological topographic characteristics of K0 ＋ 400 ~ K1 ＋ 498 high loess slope in South Slope—Ci＇en Temple section of Lanzhou,Gansu Province,the finite element software is used to simulate the slope support and unsupported working condition. The deformation of the slope,the distribution of the plastic zone and the stability of the slope are compared and analyzed under two working conditions. Analysis shows： the trend of horizontal displacement increment of the points at all levels of unsupported excavation and timely supported excavation is basically the same and the horizontal displacement is pointing to the outside of slope,the horizontal displacement in the middle of the slope is the largest and the horizontal displacement in the top of the slope is the smallest. In the vertical deformation,the high measurement point shows a larger deformation than the low measurement point under the support and unsupported conditions,the largest vertical deformation occurs in the top of the slope,unloading rebound appears in each level of excavation. It can be shown that the support measures can effectively reduce the horizontal and vertical deformation so as to maintain the slope stability.