层状围岩隧道交叉结构地震方向敏感性分析

Sensitivity analysis of seismic direction of intersecting structure of tunnel in layered surrounding rock

依托某层状围岩深埋铁路隧道工程,以主线单线隧道与横通道正交结构为研究对象,通过ABAQUS建立有限元分析模型。选取12条地震波数据,模拟基岩SV波地震作用,调整地震动峰值加速度和地震动入射方向,对研究结构随地震动输入方向的敏感性进行分析。研究分析得到:二次衬砌在地震入射角度为30°~45°时对地震动方向变化敏感性较低,初期支护在地震角度为60°~90°时对地震方向变化的敏感性较低,初期支护和二次衬砌在地震入射角度为45°~60°时对地震动方向变化敏感性较大;受力最不利的地震入射角度为15°~45°;位于主隧道与横通道交叉口拱脚附近二次衬砌受地震方向影响最敏感,横通道拱脚靠近主隧道5 m范围初期支护受地震方向影响最敏感。

This paper relies on the deep buried railway tunnel project in a layered surrounding rock,and regards orthogonal structure between main tunnel and cross passage as the analytic target of the case.The finite element analysis model is established by ABAQUS.Twelve seismic waves are selected to simulate the seismic action of bedroom-SV wave.By adjusting the peak acceleration and the direction of ground motion incident,the sensitivity of the input direction of ground motion of the studied structure is analyzed.The results show that the secondary lining is less sensitive to the change of seismic direction when the earthquake incidence angle is 30°to 45°and the primary support is less sensitive to the change of seismic direction when the earthquake incidence angle is 60°to 90°,and the primary support and secondary lining are more sensitive to the change of seismic direction when the earthquake incidence angle is 45°to 60°in the research structure.The most disadvantageous earthquake incidence angle of the structure is 15°to 45°.The most sensitive part of the secondary lining affected by the earthquake direction is located near the arch foot of the intersection of the main tunnel and the cross passage.The most sensitive part of the primary support affected by the earthquake direction is located at the arch foot of the cross passage 5 m away from the main tunnel.