Abstract
Mountain tunnels are generally thought to be less susceptible to seismic damage. However, tunnels often suffer seismic damages such as cracks and compression failure depending on the magnitude of the earthquake and the distance from the epicenter. Authors paid attention to the seismic damage of tunnels in poor geological conditions and performed model tests and numerical analyses to clarify the mechanism of seismic damage to tunnels as well as the aseismic performance of tunnel lining. It was revealed that actual earthquake damage was able to be reproduced by the model tests, in which loading conditions and structural defects were modeled. From the model tests and numerical analyses, it was found that the void above the lining have negative effects on the aseismic performance. The tunnel rigidity can be effectively increased by constructing the invert, resulting in the reduction of tunnel deformation, especially heaving at the invert. However, as the stress in the lining is also increased by the invert when large ground displacement is expected, another countermeasure is necessary to prevent the failures caused by the overstress of the lining.
