The Mechanism behind Seismic Damage to Railway Mountain Tunnels and Assessment of their Aseismic Performance

In this study, the authors performed case studies and model experiments to investigate the mechanism behind seismic damage to mountain tunnels and their aseismic performance, and the conditions under which such damage tended to be severe were clarified. Model experiments were performed with focus on damage to shallow tunnels or those in ground characterized by poor geological conditions, and the degree and extent of disasters caused by mountain seismicity were successfully reproduced. The experiments clarified the damage mechanism and seismic performance of tunnels in question. It was concluded that sound tunnels and those with inverts are less susceptible to seismic damage, and it was also confirmed that such damage tends to be greater when tunnels have voids above the lining and a lack of thickness, or when local displacement acts on them.