地震对交叉隧道影响机制及抗震方案研究

Research on the Effect Mechanism of Earthquake on Cross Tunnel and the Aseismic Scheme

研究目的:因立体交叉隧道会同时受到来自入射、反射、绕射等地震波导致的震动,其所受影响相比一般隧道而言更大。因此,对立体交叉隧道受地震荷载作用下隧道结构动力响应规律进行定量分析,分析确定影响隧道结构主应力各因素敏感性,从而优化抗震方案。研究结论:(1)对立体交叉隧道净距、围岩级别、隧道埋深等因素对隧道结构加速度、应力以及位移的响应规律进行定量分析,得到隧道净距、埋深的增大和围岩变好对交叉隧道的抗震有利;(2)地震作用对交叉隧道的上跨隧道和下穿隧道影响敏感性大小都依次是围岩级别、隧道净距和隧道埋深;(3)改变隧道衬砌混凝土的强度抗震方案效果不明显,设置隔震层效果显著,但增加隔震层厚度对抗震影响较小;(4)本研究成果可为立体交叉隧道在地震荷载作用下的抗震设计提供指导。

Research purposes： Because of fly-over crossing tunnels can be subject to shocks from incident waves,such as incident,reflection and diffraction,their impact is greater than the common tunnel. Therefore,the dynamic response law of tunnel structure under seismic load of fly-over crossing tunnel is analyzed quantitatively,the sensitivity of various factors affecting main stress of tunnel structure is analyzed and identified,and the aseismic scheme is optimized.Research conclusions：（1） The influence of the distance between the tunnel,the surrounding rock level and the depth of fly-over crossing tunnel on the response laws of the acceleration,stress and displacement of the tunnel structure is analyzed quantitatively,it is concluded that the increase of tunnel spacing,burial depth and the better surrounding rock is beneficial to the seismic resistance of cross tunnels;（2） The sensitivity of seismic action to the upper and lower tunnels of the cross tunnel is in the order of the grade of surrounding rock,net distance of tunnel and the depth of tunnel;（3） The effect of changing the strength of the tunnel lining concrete is not obvious,and the effect of the isolation layer is remarkable,but increasing the thickness of the isolation layer has little effect on the tunnel earthquake resistance;（4） The research results can provide guidance for the aseismic design of the fly-over crossing tunnel under seismic loading.