断层破碎带注浆加固对跨断层隧道减震效果的试验研究

Shaking Table Tests on Seismic Mitigation Effect of Grouting Reinforcement in Fault-crossing Tunnels

隧道跨越断层区段是地震中最容易发生破坏的区域之一。为研究注浆加固断层破碎带对于跨断层隧道的减震机制与效果,设计了断层内有、无注浆加固的2种模型,采用1-g振动台试验,输入汶川地震动记录,测试隧道衬砌的加速度响应和应变响应时程。分析试验结果发现,跨断层隧道的最大加速度响应和最大Arias烈度均位于断层破碎带与上盘岩体交界处,隧道衬砌最大动应变分布在该交界面侧的隧道拱肩部位和断层破碎带侧的拱底部位;注浆加固可以显著减小该处的加速度响应和Arias烈度,并降低隧道衬砌环动应变沿纵向的差异。通过注浆加固破碎带提升断层内隧道周围的地层物理力学特性以减小隧道纵向地层性质差异,可以有效减小跨断层隧道的加速度放大效应与变形差异。

Tunnel sections crossing fault zones are among the most vulnerable areas to damage during earthquakes.To investigate the seismic mitigation mechanism and effects of grouting reinforcement in fault fracture zone for fault-crossing tunnels,two models with and without grouting reinforcement within fault were designed.A 1-g shaking table was utilized to input the Wenchuan earthquake ground motion records,and the acceleration and strain responses of the tunnel lining were tested.The test results revealed that the maximum acceleration response and Arias intensity of the fault-crossing tunnel were located at the interface between the fault fracture zone and the hanging wall,with the maximum dynamic strain of the tunnel lining distributed at the shoulder of the arch shoulder near the interface and the invert of the arch near the fault fracture zone.Grouting reinforcement significantly reduced the acceleration response and Arias intensity at this location while decreasing the longitudinal differences in the dynamic strain of the tunnel lining.By enhancing the geotechnical mechanical properties surrounding the tunnel within the fault through grouting reinforcement of the fracture zone,the acceleration amplification effect and deformation differences of the fault-crossing tunnel can be effectively reduced,thereby minimizing the longitudinal differences in the tunnel's geological properties.