穿越断层长大深埋隧洞动力非协调变形与破坏机制

Dynamic Incompatible Deformation and Failure Mechanism in A Long Deep Buried Fault-crossing Tunnel

摘要:

强震作用下穿越断层破碎带长大深埋隧洞的动力问题一直是深部地下工程研究的热点问题，保障震后隧洞的安全和稳定通行是灾后救援的关键。为了深入探究穿越断层长大深埋隧洞围岩地震动力响应，依托于香炉山隧洞工程，采用室内振动台试验与理论分析相结合的方法，开展不同断层倾角下隧洞围岩动力响应定性定量分析，揭示强震作用下穿越断层长大深埋隧洞动力变形规律，结果表明：强震作用下，当断层倾角为30°时，隧洞围岩的动力响应最为显著，断层破碎带处峰值加速度、峰值应变以及峰值位移变化最为强烈。基于振动台试验结果发现，隧洞围岩的动力响应存在显著的断层放大以及上盘效应，并因此产生隧洞围岩的非协调变形，这是导致穿越断层长大深埋隧洞变形破坏的主要原因。香炉山隧洞穿越断层或近断层位置处，振动荷载叠加作用以及残余拉压应力引起隧洞循环往复的张拉、压缩和错动，导致纵向、横向及环向裂缝的出现，进而产生大变形甚至破坏。研究成果可以为强震区长大深埋隧洞工程稳定性分析和安全评估提供指导和借鉴。

Abstract:

Dynamic problem of the long deep burial fault-crossing tunnel has always been a hot issue in deep underground engineering. It is the key to ensure the safety and stability of the tunnel after earthquakes post-disaster rescue. To explore the dynamic response of the surrounding rock of the long deep fault-crossing tunnel, relying on the Xianglushan tunnel project, the indoor shaking table tests and theoretical analysis were illustrated to explore the dynamic response of the tunnel surrounding rock under different inclination angles. Finally, the dynamic deformation and failure mechanism of the long deep buried tunnel were revealed, draw the conclusions: Under strong earthquake load, the dynamic response of the tunnel surrounding rock was the most significant when the inclination angle was 30°, and the peak acceleration, peak strain and peak displacement of the fault were the most intense. The dynamic response suggested the significant fault amplification and hanging wall effect by shaking table tests, which caused the incompatible deformation of the tunnel surrounding rock. This dynamic incompatible deformation caused the deformation and destruction of the long deep buried fault-crossing tunnel. The Xianglushan tunnel near-fault and cross fault locations was induced a cyclic back-and-forth tension, compression and dislocation by vibrational loads and residual tension-compressive stress. The longitudinal, transverse and annular cracks were produced to lead large deformation and even destruction. The research results can provide guidance and reference for the stability analysis and security assessment of the long deep buried tunnels in a strong seismic area.