The Cause of Shallow Tunnel Collapse and Simulation Analysis of Consolidation for a Collapsed Tunnel

In order to ensure the safety of the shallow tunnels construction, it is very important to find the reasons of the collapse. During Fujiachong tunnel construction, collapse of the section Yk25 + 547～Yk25 + 552. Distributions of cracked surrounding rock, rainfall, geological forecast were discussed for reason of tunnel collapse. According to in-situ construction condition, reinforced support program was applied to the surrounding rock consolidation of the tunnel. In order to assess consolidation effect, a cross-sections of collapse zone measurement was increased and simulation analysis was applied to the section. The results of in-situ measurement and simulation results show that tunneling collapse zone was consolidated by reinforced support program successfully.