Abstract:
The construction of shallow-buried ;oess tunnel portals is key to the safety of tunnel break-in. Based on the portal construction of the Gujiping double-track railway tunnel with a designed speed of 200km/h in surrounding rock of grade V, this paper introduces advance pre-reinforcement with large pipe-roof and three-bench and seven-step construction technology. The results indicate that this construction method is both rapid and effective, guaranteeing construction safety.