2021 Volume 77 Issue 1 Pages 1-16
The deformation suppressing effect of mountain tunnel reinforcement works for deformed mountain tunnels in service are evaluated by numerical analysis. It is found that the back-filling has a limited effect by itself. It is found that the rock-bolting has the effect even by itself, and that the effect increases as the number of rock bolts increases, and there is a length that the effect does not increase any more, which is related to the size of the fracture region. It is found that the effect of the liner reinforcement is small by itself, but the effect becomes apparent when liner reinforcement is used in combination with the back-filling. It is considered that the liner reinforcement should be used in combination with the back-filling and the rock bolting, only when the deformation is large and large effect is required. Based on these results, the selection criteria of reinforcement work and the prediction method of reinforcement effect are proposed so that it can be applied in practice. Moreover, the validity of the method is confirmed by the verification analysis of the actual deformation tunnel.