Study On A New Type Structure For Tunnel Reinforcement At Landslide Site

With the advance of Chinese economic construction, transport requirement of the central and western regions dramatic increase, leading to the emergence of a variety of high-grade road and rail. Because of the central and western regions of complex terrain and geological conditions, road or rail routes often pass through poor geological sections, so routes inevitably are affected by such geological disasters. Tunnel in landslide (tunnel was built in the landslide) has different degrees of disease which seriously affect the normal operation of routes. In the thesis, a method of partial reinforcement is proposed when the direction of landslide and tunnel axis has a big angle and tunnel is located near the sliding surface, which makes the cost of treatment greatly reduced, the new reinforcement structure is systematically studied, the main contents and results are as follows:(1) Tunnel in landslide has been classified according to the spatial relationship between landslide and tunnel, tunnel deformation characteristics, landslide tunnel and landslide interaction characteristics, and the deformation characteristics of each type have qualitative analysis, the geo-mechanical models are summaried; on this basis, a new reinforcement ideas and new representative reinforce structure which is anchorage and drag solid structure is proposed. The reinforcement principle of new structure is fully use tunnel lining, which is not only as transport facilities, but also as a part of sliding structure, this reinforcement means use anchors through sliding surface to let tunnel fix in stable bedrock, lining is used as anchor anti-force device, the location of slip surface is changed.(2) Two type of landslide tunnel which are tunnel through landslide and tunnel in landslide are discussed, then the struture of the new reinforcement struture is analysised, internal force and the theoretical formula of deformation are obtained, the influence of the new reinforcement structure internal forces has a correlation analysis by the change of the main parameters, results show that:the displacement and internal force of the tunnel structure increases linearly with the landslide force change; the displacement and internal force of the tunnel structure increases curved shape with the thickness and the anchor stiffness change; the landslide stability coefficient notablity increase by using the new structure to reinforce the tunnel.(3) The proposed new structure and method of reinforcement is used in high Beach station landslide of the second-line Xiangfan-Chongqing, the formation mechanism of landslide and landslide features, the landslide stability of before reinforcement and after reinforcement is analysised, the results show that the stability improves obviously, the stability coefficient change from 1.01 to 1.16. (4) The displacement and internal force of the tunnel structure are calculated by use the numerical software to simulate the new structural to reinforce the high Beach station landslide, the results show that the new structure is effective and feasible, the internal force and displacement of reinforcement structure is very small, the stability improves obviously, the stability coefficient change to 1.21.