Research on the Effect of Risk Mitigation Measures Against Earthquake for Mountain Tunnel Through Static Loading Test

摘要

Rock tunnels are generally considered to have the required structural strength to resistrnearthquakes; recently, however, a number of rock tunnels in Japan have suffered severe earthquake damage torntheir permanent lining. Although several countermeasures are available to mitigate the risk of such damage,rntheir mechanism and effect are not fully understood. In this study, static loading experiments assuming arnmountain tunnel affected by an earthquake were carried out to clarify the mechanism of lining damage and therneffect of countermeasures. The results revealed that the presence of void spaces behind the lining reduces thernstructural load-bearing performance, especially in tunnels constructed by conventional timber lagging method.rnMoreover, reinforcement such as inverted arch, rock bolts, lining rebars and carbon-fiber sheets for innerrnsurfaces can potentially mitigate the risk of lining collapse due to earthquake.