特大断面隧道断层段地震响应与断层构造关系

针对特大断面隧道断层破碎带地震响应强烈而导致衬砌结构更易遭受破坏的问题,本文采用FLAC 3D仿真计算软件,通过数值模拟,研究特大断面隧道地震与断层宽度、断层倾角的关系,分析衬砌地震响应规律,确定抗震薄弱位置及抗震设防范围。分析结果表明：断层处的衬砌横断面上的拱腰和拱脚处属于抗震薄弱位置,需要在这些位置处重点进行设防；断层上盘位置对地震响应更明显,应加强这些位置上隧道衬砌的抗减震措施；地震时,小倾角,大宽度的断层构造对特大断面隧道的影响大。在本文研究的断层构造范围内,特大断面隧道的抗震设防区域选取应为：断层及断层交界面前后各取25~30m的区域。这些结果可为地震区的特大断面隧道设计建设提供参考。

Study on the relationship between seismic response and fault structure in fault section of extra-large section tunnel

Aiming at the problem that the lining structure is more susceptible to damage due to the strong earthquake response of the fault fracture zone of extra-large section tunnel and ensuring the safe use of the tunnel, this paper studied the relationship between earthquake and fault width and fault dip angle of extra-large section tunnel by using FLAC 3D simulation software. The seismic response law of lining was analyzed, and the seismic fortification range and seismic weak position were determined. The results show that the waist and the feet of the arch in the cross section of the lining at the fault are seismically weak and need to be fortified at these locations. The seismic response of the wall of the fault is more obvious, and the seismic mitigation measures of the tunnel lining at these positions should be strengthened. During an earthquake, faults with small dip angle and large width have a large impact on very large cross-section tunnels. The seismic fortification area of extra-large section tunnel should be selected as follows:: the area of the fault and the interface of the fault should be 25~30m each. These results can provide a reference for the design and construction of extra-large section tunnel in the earthquake area.