Support Structure Internal Force Monitoring and Analysis for Undercut Metro Tunnel in Crossing the Existing Line

The ground surface settlement and deformation of existing tunnels of subway stations undercut with shallow overburden have important effects on the construction safety.This paper introduces the processes of tunnel excavating of the Xidan station of Beijing subway line 4 Xidan station.A scheme for monitoring structural forces is drawn up.The trends of structural forces and rock pressure are under control, and the reference information is provided to judge the stability and safety of the tunnel by monitoring information feedbacks.