Study On Calculation Method And Seismic Response Characteristics Of Seismic Fortification Length Of Highway Tunnel In Qiangshaoshan Area

When tunnel’s damage accumulates to a certain extent it will have an irreparable damage in view of the great harm of "5.12-Wenchuan-earthquake" in2008. In order to prevent the instability of tunnel’s portal induced by the strong seism, this paper combined the highway tunnels of Wenchuan earthquake with other seismic damage investigate information at home and abroad. This paper used literature research methods to analysis characteristics and influence factors of mountain highway tunnel’s seismic damage under the action of earthquake based on the project of the study in the evolution and mechanism of tunnel’s portal instability induced by earthquake. Seismic fortification length of tunnel’s opening period was derived and the correctness of the results was verified through the practical engineering. The main contents of this paper are as follows:1. Achievements and shortcomings of domestic and foreign scholars were inductive on fortified length of the tunnel entrance in seismic region. General rules of the dynamic response were obtained. Instability of surrounding rock and seismic inertial force caused untold damage to the entrance and the body of tunnel. The entrance of tunnel was a weak link on the grounds of18typical portals which were badly damaged.2. Oscillatory differential equation of tunnel structure was established, and the internal force and deformation of lining were analysed. Fortified length could be worked out based on knee point.3. The three-dimensional models of tunnel were established according to practical engineering tunnel which were applied to seismic acceleration or stress at the bottom. The effects of length could be got in the night of variation rule of internal force in different factors.4. The position of the damage in tunnel was painted. On the basis of the different distribution of earthquake damage along the axial direction of tunnel, the rationality analysis’ results and numerical analysis’ results were valid to make reference to the tunnel seismic fortification.