土岩软硬结合部隧道结构的震害机理分析及抗震研究

Analysis and Study of the Seismic Failure Mechanism and Aseismic Measures of a Tunnel Structure in the Rock-Soil Interface Area

在土岩软硬结合部,土体与岩体由于刚度、质量密度等力学参数不同而产生不同的地震动响应,继而导致隧道结构发生严重破坏。文章结合青岛海底隧道相关资料,研究分析了地震灾害来临时隧道结构在土岩软硬结合部位的破坏机理及相关抗震措施。研究结果表明,在土岩软硬结合部,地震动作用下的围岩失稳、大的地震惯性力,以及大能量基岩面波产生的变形能都会导致隧道衬砌发生破坏,而大能量基岩面波产生的变形能是主要原因;当保持围岩稳定或使隧道结构的质量密度、刚度与围岩相差不大时都可以防止土岩软硬结合部隧道结构发生破坏,而后者是最有效的途径;轻质量延性隧道的抗震性能良好。本研究成果对于揭示土岩软硬结合部隧道结构的震害机理及优化抗震设计具有一定的借鉴意义。

Because of different mechanical parameters such as stiffness and mass density, rock and soil may have different seismic responses in the interface area of a tunnel project, thereby causing serious damage to the tunnel structure. Based on a theoretical analysis and numerical simulation of the Qingdao subsea tunnel, the seismic fail- ure mechanism and related aseismic measures of the tunnel structure at the rock-soil interface area were studied. The results show that rock failure, great seismic inertia forces induced by ground motion, and deformation caused by a large magnitude bedrock surface wave may result in damage to the tunnel linings in the rock-soil interface area, of which the last factor is the main cause; the damage to the tunnel structure can he prevented in the rock-soil inter- face area if the surrounding rock is kept stable and the differences in the mass density and stiffness between the tun- nel structure and surrounding rock are minimized, the latter of which has proved to he the most effective; and a tun- nel structure with light support and ductility has better seismic behavior. The results can be used as a reference for the study of seismic failure mechanisms and for the optimization of seismic design regarding tunnel structures within the rock-soil interface area.