基于同震位移的隧道抗震设计及其工程应用

Seismic Design and Engineering Application of Tunnels Based on Coseismic Displacement

首次在隧道抗震设计中考虑地震同震位移场,通过搜集历史地震破裂信息估计工程区地震位错,采用"分裂节点法"获得隧道周边的同震位移场,并联合拟静力隧道抗震设计方法,成功应用于某公路隧道。研究表明:基于同震位移的隧道抗震设计方法能够为我们估算未来可能的地震灾害提供有力的定量分析工具;当地层自振周期和基岩反应谱未知,可以利用同震位移场估算远场剪应变开展隧道拟静力抗震设计;例如对于云南某隧道,如果龙陵—澜沧断裂带发生地震,隧道南北两端强制位移约为6 cm。如果龙陵—瑞丽断裂发生地震,由于强制位移导致隧道南北部分出现反向运动,将会对隧道中部产生剪切作用,且隧道出现明显的横向和垂向差异运动。

In this work,the theory of the coseismic displacement field is first considered in the aseismic design of tunnels.We estimate earthquake dislocation in the engineering area by collecting historical earthquake rupture data.The coseismic displacement field around the tunnel is calculated through the splitting nodes method and applied in combination with the pseudostatic method in the aseismic design of a highway tunnel in Yunnan Province.Results show that the method based on coseismic displacement for the aseismic design of tunnels can provide a powerful quantitative analytical tool for the estimation of possible future earthquake disasters.If the natural vibration period and bedrock response spectrum are unknown,the coseismic displacement field can be used to estimate the far-field shear strain when conducting the quasistatic aseismic design of the tunnel.The forced displacement of the north and south segments of a tunnel in Yunnan is approximately 6 cm if earthquakes occur along the Longling-Lancang Fault Zone.If earthquakes occur along the Longling-Ruili Fault,forced displacement will cause reverse movement in the north and south parts of the tunnel.These movements will exert a pronounced shear effect on the middle of the tunnel,and lateral and vertical differential movements in the tunnel will intensify.