| Thus far, mountain tunnels constructed in bedrock generally have not suffered severe damage during earthquakes, excluding tunnels in sections with extremely poor ground, such as fault fracturezones and tunnel portals. Consequently, it was thought experience proved that tunnels were highly earthquake-resistant structures. However, during the Mid Niigata Prefecture Earthquake in 2004 in Japan, relative large damage, which was in a limited number of locations, occurred in areas that were thought to be resistant to seismic damage. Such damage included collapses of tunnel linings. It is important to elucidate the mechanism of seismic damage and to establish rational earthquakeresistant measures in order to minimize this kind of damage, because Japan is a country with numerous tunnels and earthquakes.In this study, as a first step to clarify the mechanism of seismic damage, we have conducted numerical analyses to simulate actual damages suffered by the earthquake in 2004. In addition, we have conducted shaking table test to investigate basic behavior of tunnel in soft ground. |
