多级边坡开挖与锚固的影响范围数值模拟

Numerical Simulation for the Influence Range of Excavation and Anchoring on Multi-level Slope

采用FLAC3D对岩土多级边坡施工过程进行系统的数值模拟,探究多级边坡在开挖时引起的松弛区范围和锚索在锚固时引起的坡体预压区范围以及两者相互影响的作用机制。结果表明:多级边坡开挖与锚固引起的坡体变形均大致呈圆弧状。预应力锚固时,在一定范围内坡体预压区随着预应力的增大而增大,但当预应力增大到一定程度,坡体预压区边界不再有明显扩展。施加预应力能有效缩小下级边坡开挖引起的松弛区范围,所以高边坡施工应遵循"逆作法"原则,边开挖、边加固,一次开挖量不能过大。预应力锚固引起的坡体预压区与该级边坡开挖形成的松弛区在形状上非常相似,说明施加预应力能有效恢复开挖引起的土体松弛变形,从而提高边坡的稳定性和安全性。

FLAC3Dis adopted to perform numerical simulations for the construction process of geotechnical multi-level slope,aiming at exploring the relaxation zone caused by slope during excavation and precompression zone caused by the anchor during an-choring, as well as the mechanism of action on the interaction of both zones. The results show that the slope deformation rangecaused by slope during excavation and anchoring is roughly circular shape. When pre-stressed anchorage operation happens, withina certain range, slope precompression zone increases with the increase of pre-stress. While pre-stress increases to a certain degree,the boundary of slope preloading area will extend slightly. Pre-stressing can effectively reduce the relaxation zone caused by the low-er slope excavation, therefore, the construction of high slope should follow the principle of reverse construction method, making rein-forcement while excavating, and make control of the excavated volume every time. The slope precompression zone caused by pre-stressed anchorage operation has a very similar shape with the relaxation zone caused by the side during excavation, which meansthat adding pre-stress can effectively restore the relaxation deformation of soil caused during excavation, so as to improve the stabili-ty and safety of slope.