CONSTRUCTION METHOD OF CLOSE PARALLEL TUNNEL FOR EXCAVATING AND REINFORCING TUNNEL PILLAR PORTION ACCORDING TO GROUND CONDITIONS

摘要

Regarding the excavation of tunnel pillars, it is possible to improve the workability and shorten the construction period by applying the tunnel pillar reinforcement method in connection with the tunnel's excavation plan (front end and upper and lower half digging), leading tunnels and trailing tunnels. By forming an anti-vibration cutting line using a wire saw against the pillar, it is possible to minimize the impact of the blasting vibration of the base of the pillar of the tunnel, thereby maximizing the tie bolt support effect and increasing stability, and also strengthening the tunnel pillar In relation to the above, after the pre-drilling of the preceding tunnel, the steel pipe rock bolt of the tie-bolt system was pre-installed, and after performing the role of the rock bolt, the tie-bolt was immediately inserted into the steel pipe rock bolt immediately after excavation of the trailing tunnel to immediately reinforce the pillars, thereby gradually stepping into the tunnel pillar. It is possible to increase the stability of the pillar part by the construction of the tie bolt immediately, and it is easy to change the application plan of the tie bolt considering the ground conditions identified in the excavation of the preceding tunnel, thereby securing the stability, constructability and economy of the tunnel pillar part considering the ground conditions. Providing a method for constructing a close-up parallel tunnel that excavates and reinforces a tunnel pillar according to ground conditions.