Study On Seismic Response Analysis And Anti-seismic Measures Of Highway Tunnel In High Intensity Region

China is an earthquake-prone country, the earthquake areas are broad and scattered, the earthquakes are frequent and intense. Tunnel is an important social infrastructure, which once is seriously damaged in the earthquake not only can not play the role of lifeline, but also even become a hindrance against disaster relief. In order to reduce the losses caused by earthquake, the research on seismic response and aseismic and damping seismic measures for tunnel structures is imminent, related research in high intensity fortification area is even more important. This paper takes a highway tunnel project in a high intensity region as the background. In order to grasp the dynamic response mechanism of tunnel in high intensity region, seismic dynamic response and aseismic technology of the tunnel was researched, the following aspects were analysed, and some basis for the study on the law of stability of tunnel in high intensity region was provided.Firstly, the macroscopical seismic damage datas of the tunnel in the world were collected, and the damage situation and typical seismic damage of the tunnel were analyzed with earthquake magnitude, focal mechanism, seismic oscillation and intensity distribution. The seismic damage mechanism and the influence factors of the seismic damage of the tunnel were analyzed through the macroscopic seismic damage of tunnels. It was obtained that the seismic damage mechanism of tunnel structure is mainly divided into three categories of damage caused by seismic inertia force, damage caused by seismic forced displacement and damage caused by surrounding rock’s losing stability; and the factors causing serious damage to the tunnel generally include seismic parameters, the conditions of surrounding rock, fault, tunnel buried depth, tunnel condition etc.Secondly, the numerical simulation calculations of tunnel structure was carried out from three aspects, that is, inputting peak ground acceleration of different sizes, changing the stiffness of the primary support and secondary lining, setting different buried depth. The maximum axial force, maximum shear force and maximum bending moment on monitoring points of the secondary lining section of the tunnel were analyzed, and the laws of seismic dynamic response of the tunnel was obtained. The maximum axial force, maximum shear force and maximum bending moment of the secondary lining section are continuously increasing along with the increase of the peak acceleration of the earthquake wave, and the distribution of the internal force is more and more uneven. Only increasing the stiffness of the primary support is conducive to reducing the maximum shear force and maximum bending moment of the secondary lining section, and the maximum axial force of all parts of secondary lining section are increasing by only increasing the stiffness of the secondary lining, and the effect of increasing the stiffness of secondary lining is greater than that of increasing the stiffness of primary support. With the increase of tunnel buried depth, the internal forces of the secondary lining section show a gradual downward trend basically.Finally, the rubber was selected as damping material for the tunnel in high intensity region by comparing and consulting a large number of relevant information, the shock absorption layer was set between the primary support and secondary lining of the tunnel, the shock absorption layer of different thickness and different arrangement range was considered, the damping effect in each program was compared and analyzed. The calculation results show that the seismic response of tunnel can be effectively reduced by setting the shock absorption layer, and the effect of the arrangement range is greater than the thickness for the shock absorption layer. The program of 5cm thick rubber shock absorption layer setting along the whole section except inverted arch section was recommended eventually for the research object of this paper.