The Optimization Of Tunnel Shed Structure Of Highway In The Mountain Area

With the development of the country's economy, more and more high-level driveway will be constructed in the western mountain area to meet the need of the economic development. However, the application of the routine supporting structure which would induce geologic disaster in the side slope is restricted by the intricacy geologic and hydrologic aspect. It is a stringent demand to find an appropriate structure which can keep the security of the highway and protect the ecologic environment in the mountain area. The shed tunnel structure won the favor of the deviser because it compromises the characteristic of supporting and environmental protection, It will play a big role in the western highway construction.Firstly, this paper summarized the representative form of the tunnel shed as proving the advantage of the structure in the western mountain area. And then research the coupling relationship between the side slope and tunnel shed in order to find a more reasonable theory in shed design. On the other hand, through the numerical analysis of shed tunnel by FEM program ANSYS, this paper try to optimize the structure on the base of the four structure style, which want to find a rational structure style of the tunnel shed. At last, combined with the example of a program, this paper have demonstrated the technical possibility and environmental advantages of using shed tunnel in shallow buried, unsymmetrical pressured and valley zones besides river. Then we believe that the new style of structure using shot-concrete-bolt support and shed tunnel is reasonable and safe, for it take the advantage of the shot concrete-bolt support and the support function of shed tunnel fully, which makes it to be a perfect system under stress. The calculator indicates that if the temporary stability of the slope was promised to be enough, the permanent stability of the slope can be ensured once the shed tunnel's structure was constructed, so the shed tunnel engineer reduces the excavation of hillside, which can protect the surrounding original environment and then can reduce the disturbance of the natural geology and the possibility of inducing the hazard of geology. So we can draw a conclusion that it is proposed to construct shed tunnel or half tunnel accommodating the topography to accomplish a purpose of protecting environment in shallow buried, unsymmetrical pressured,and valley zones besides river.