The Seismic Dynamic Response Study Of Mountain Tunnel Three- Dimensional Cross Section

Traditional thinking that tunnel structure under surrounding soil constraint, do not need to consider the structure seismic problems.But around the world all previous earthquake, the underground structure has suffered destruction in various degrees, tunnel engineering seismic problems gradually cause the attention of the researchers. Mountain tunnel vertical cross section in the spatial structure form is more complicated than conventional tunnel, the seismic dynamic response study in the cross section, will definitely strengthen our understanding about the action of the cross section stability and safety.has certain scientific research significance.With chai jia-ying double line highway tunnel nearly under pass the existing railway tunnel project as an example, analysis of different level of highway tunnel vertical interval, and iron in tunnel clear distance, direction of seismic wave excitation, resistance to shock absorption measures related to the influence of the cross section stress and displacement peak, so as to provide seismic fortification reference for similar projects.The results show that:(1) Horizontal interval is beneficial to reduce with the increasing of highway tunnel in Mises stress value, Also have certain influence to railway tunnel; The increase of vertical interval can increase the highway tunnel Mises stress, Railway tunnel dynamic response will change too, Displacement of highway tunnel with small change, railway tunnel displacement is not to change.(2) Direction of seismic wave excitation can significantly influence on dynamic response of cross section, main show is xyz three direction combination the tunnel structure displacement and stress in the most adverse, y direction separate the tunnel affected minimum, displacement value is 1/10 of the xyz together.(3) Set the shock absorption effect of shock absorption layer of highway tunnel, will greatly reduce the Mises stress value, but the displacement value is slightly enlarged, damping effect by the thickness of damping layer and stiffness ratio. Settings damping layer may cause adverse effects on railway tunnel, the influence degree depend on damping layer parameters.(4) Set buckstay of highway tunnel seismic effect, but the effect is not as good as stress reduced damping layer, and the stress change along the tunnel longitudinal distribution, seismic effect associated with reinforcement ring thickness and strength. Set reinforcement ring will also affect the railway tunnel, but less adverse influence to set the shock absorption layer.