Numerical Simulation For The Seismic Response Of Unsymmetrically Loaded Tunnel Entrance

The mechanics of the portal part of unsymmetrically loaded tunnel is different from that of common tunnel, so the dynamic response behaviors of them will be also different. This paper has simulated the seismic response of the portal part of Huangcaoping No.1 tunnel by using FLAC(3D), and has discussed the earthquake response characteristic of surrounding rock and lining of the portal part from the aspects of the plastic zone, stress, displacement and acceleration. The findings indicate that the side against mountain is weak in earthquake-resistance of tunnel, so the strengthening measures should be done in this part. Based on the orderliness of acceleration of surrounding along the axial direction of the tunnel, the anti-seismic fortified length in tunnel outlet of Huangcaoping No.1 tunnel can be gotten as fifteen meters.