The Study Of Mechanical Behavior Of Highway Tunnel Going Through The Existing Interurban Railway Tunnel

With the development of underground transport and the limited land resources, the adjacent project is common. When the new tunnel goes through the existing tunnel, the effect to the existing tunnel should care.Relying on one highway tunnel that go through the existing inter-city railway tunnel project, this paper analyzes the mechanics theory of construction on the basis of summing up the domestic and foreign scholars’ research and study two methods go through inter-city railway tunnel. The main research approaches is numerical simulation that use the FLAC3 D software. The longitudinal additional bending moment of lining and displacement and deformation of the existing inter-city rail tunnel was analyzed by simulating construction process. The main conclusions are obtained at:1) In the project by relying, existing tunnel had little effect on the surrounding rock displacement field by underground excavation and open cutting.2) In underground excavation contour extension to the ground, but contour extension to the ground using open cutting, and the line should be designed to avoid cross.3) The construction of new project has less influence on the state of tension or pressure of surrounding rock, and the key is to control the deformation of existing tunnel.4) In the approaching construction for two neighboring parallel tunnels the distribution of vertical deformation of existing tunnel in both horizontal and vertical direction along the tunnel longitudinal uniform, but near the intersection point, the bigger the deformation value is for up-down crossover tunnel approaching excavation.5) Inter-city railway tunnel deformation caused by the approaching construction for two neighboring parallel tunnels is easily adjustment.6) The construction process mechanical calculation of parallel and cross tuunels cannot be considered in plane strain, but the normal operation of mechanical analysis is available for operations of parallel tunnels.7) The existing tunnel structure deformation of open-cut scheme is dramatically less than that of excavation scheme.