Study On The Influence Of Adjacent Excavation Construction On Existing Tunnels And The Countermeasures

With the development of national economy, the demand for transportation infrastructure construction is increasing. Main roads of high level are under unprecedented development. The construction of subway and tunnel has become the main measure to alleviate the traffic jams. At the same time, the accelerating process of urbanization will certainly result in large underground space using. Those will inevitably emerge the excavation project above the existing tunnel. When initial depth is small, it will strongly influence the existing tunnel.This paper based on the project of National Natural Science Foundation of China’the study of influence division and countermeasures of fill or excavation construction above existing tunnel’. During the indoor model test and numerical simulation, the influence rules of the excavation above the existing tunnel have been studied by considering surrounding rocks, tunnel structural soundness and initial buried depth. Based on test results and projects, the influence division and countermeasures have been obtained.1) The model test uses similar material simulating three grade level surrounding rocks, two kinds of tunnel structural soundness and three initial buried depths.2) Numerical simulation use to support and verify the model tests. By comparing the data from test with the data from numerical simulation, the problems of model test and finite element analysis have been analyzed, and the excavation Influence rule caused by the surrounding rocks, structural soundness and initial buried depths has been reached.3) The influence division of initial depth 3.6D,2.4D and 1.1D is divided by allowable stress increment, the level of surrounding rocks and structural soundness is taking into account. The countermeasures of excavation construction above existing tunnel is raised by existing tunnel, middle ground and new construction. The lian- huo high- speed expansion project has strong influence, so the project need to use beam reinforcement, the monitoring results show that the tunnel construction deformation and stress is normal.