隧道洞口开挖诱导高陡边坡滑动变形及支护研究

Deformation and Support of High and Steep Slope Induced by Tunnel Entrance Excavation

依托某高速公路隧道洞口段边仰坡大变形情况,以现场调查、数值模拟和现场监测为手段,对隧道开挖诱导高陡边坡滑动的变形及支护展开研究。据现场调查结果推测隧道洞口施工扰动是滑坡的主要诱因,滑坡进而引起古滑坡复活,两者相互作用导致隧道洞口大变形。然后采用反算B样条曲面拟合方法,通过MIDAS GTS三维有限元软件建立隧道洞口段高陡边坡三维地质模型,分析数值模拟结果可知,边仰坡开挖致使古滑坡复活,另外因隧道洞口开挖施工使得围岩变形加剧,导致坡体的深部有潜在滑移风险;采取复合式支挡结构加固边坡方案能有效抑制边仰坡滑坡和古滑坡的进一步发展,同时隧道洞口的大变形也得到控制。这与现场监测结果一致,验证了之前的推测,也进一步证明支护方案的可行性及工程实用性。

In this paper,relying on the large deformation of the uphill slope at the entrance of some tunnel,by means of field investigation,numerical simulation and field monitoring,the deformation and support of the high and steep slope sliding induced by tunnel excavation are studied.According to the results of field investigation,it is speculated that the disturbance of the tunnel entrance construction is the main cause of the landslide.The landslide in turn caused the resurrection of the ancient landslide,and the interaction between the two led to the large deformation of the tunnel entrance.Then,using the inverse calculation method of B-spline surface fitting,a three-dimensional geological model of the high and steep slope at the entrance of the tunnel was established by MIDAS GTS 3D finite element software.Excavation construction increases the deformation of the surrounding rock,leading to the risk of potential slippage in the deep part of the slope;The use of a composite supporting structure to strengthen the slope can effectively inhibit the further development of the side slope landslide and the ancient landslide,and the tunnel entrance large deformations are also controlled.This is consistent with the results of field monitoring,which verifies the previous speculation,and further proves the feasibility of the support plan and the practicality of the project.