Mechanical Response Analysis of Large Section Transverse Channel Construction in Metro Station

The safe construction of transverse channel was the premise to ensure the smooth construction of the shallow-buried excavated metro station. Based on the construction of the transverse channel of Shikui Road station of Dalian Metro Line 5, the surface settlement, the stress of the support structure and the removal length of the primary lining were analyzed by using the field monitoring data and numerical simulation. The results showed that the excavation of shaft caused disturbance to the rock at the beginning of the transverse channel, and it was necessary to adopt advanced grouting bolt to reinforce the surrounding rock before the excavation of transverse channel, so as to make up for the stratum loss. The biggest disturbance to the ground surface and rock mass was the construction of the first and second pilot tunnels on the left side of the transverse channel, and the surface settlement caused by this stage accounted for 58% of the total settlement. The area affected by the construction of the transverse channel was within 4 times the diameter of the pilot tunnel from the center line of the transverse channel. The rapid closure of the primary lining at the top of the transverse channel could effectively reduce the disturbance to rock mass and ground surface caused by the excavation of large section of the lower pilot tunnels. Based on the numerical simulation results, the removal length of the primary lining was determined to be 12 m, and its rationality was verified effectively in the actual construction. The research results could provide reference for the design and construction of similar projects.