Abstract
Some mountain tunnels in service suffer from floor heave, and some of them require countermeasures. It is considered that such floor heave phenomenon and the effect of its countermeasures are closely connected with the excavation method and tunnel structures, however no such numerical analysis study has been found. In this study, tunnel construction, floor heave during service and its countermeasures are consistently modeled in the numerical analysis. As the result, invert construction and early closure were found to be effective for preventing deformation not only during tunnel construction but also during service. Moreover, it was confirmed that in the application of rock bolts as a countermeasures to the floor heave during service, well-balanced specification of the bolts considering the surface bonding and yielding of the bolts is important for securing the long-term performance of the countermeasures.
