Effect of the auxiliary method on the seismic behavior of tunnel excavated in low overburden or soft ground condition

一般认为隧道的抗震性能较好，但对隧道的抗震性能没有进行明确的讨论。然而，对于低覆盖层或软土地基开挖隧道衬砌的地震破坏，已有现场报道。为此，进行了一系列的模型试验和数值分析，以明确在上述地基中开挖的隧道衬砌和地基的抗震性能。在此基础上，对地基改善法和足部加固法等辅助方法的效果进行了探讨，并对其作用机理进行了探讨。试验结果表明，即使在高覆盖层条件下，地震作用在隧道衬砌上的荷载也在不断增大。此外，通过安装辅助方法可以防止隧道衬砌和地面的变形。

Tunnels are thought as excel in seismic adequacy, there for the seismic behavior of the tunnels are did not clearly discussed. However, earthquake damages of the tunnel lining are reported in the field, which with the low overburden or which excavated tunnel in soft ground. Therefore, a series of the model experiments and numerical analyses are carried out to make clear the seismic behavior of the tunnel lining and ground which excavated in the above mentioned ground. Thereafter, effect of the auxiliary method including the ground improvement method and foot reinforcement method, and the mechanism of the effect are discussed. Experimental results show that, the load act on the tunnel lining is increasing during earthquake, even in the high overburden condition. Moreover, the deformation of the tunnel lining and the ground can be prevented by installing the auxiliary method.