Study on Failure Characteristics and Treatment of Tunnel Lining Crossing Active Faults

Considering the influence of active fault dislocation on tunnel lining structures and taking reasonable measures to reduce the influence of fault dislocation on these structures is helpful to ensure the safe operation of the tunnel and the safety of people’s lives and property. In this paper, through the 1:40 lining model, an indoor model test is carried out by using a self-made fault dislocation test box, and the damage characteristics of the tunnel lining structure caused by the setting of spacing and the expansion of cross-sections are explored and compared. The results show that the setting of damping joints plays an effective role in controlling the longitudinal failure of tunnels. Reducing the spacing of damping joints can further control the longitudinal failure distance of tunnels affected by fault dislocation. From the test results, the optimization effect can reach about 25%. However, the ability of a single ring to bear load decreases because of reducing the spacing of damping joints, which will make the problem of seismic resistance more prominent at the fault. To ensure an effective clearance area of the tunnel after fault dislocation, the design of enlarged sections and longitudinal damping joints can be adopted. However, it is worth noting that in the seismic design of the project, the size of the enlarged section and the joint setting distance of the damping joint should be reasonably arranged according to the strike and dislocation of the fault.