Mechanical Response Analysis of Mainline Tunnel Structures in the Full Process of Metro Shield Interval Connecting Passage Mechanical Construction

［Objective］ The mechanical method construction of connecting passages significantly impacts the internal forces within the segment structures of metro mainline tunnels. It is essential to understand the force variation patterns and weak points in the tunnel structure during the construction process to ensure its safety. ［Method］ Using the mechanical method pipe jacking construction project of the connecting passage in a Zhengzhou Metro shield interval for case study, a numerical calculation model is established using ABAQUS finite element software. A simulation analysis is conducted on the entire process of connecting passage construction to investigate the deformation of the mainline tunnel structure and the change patterns of internal forces. The reliability of the numerical model is validated by comparing the trends and locations of simulated values with those of the actual measured values. ［Result & Conclusion］ The trends and locations of changes in measured and simulated values are generally consistent, confirming the accuracy of the finite element model. During construction, the maximum deformation of the cutting ring exhibits a gradually increasing trend. The maximum bending moment of the cutting ring at the originating end first increases and then decreases, while the maximum bending moment at the receiving end initially decreases slowly before increasing. The maximum axial force of the cutting ring shows a gradual increasing trend. The maximum deformation and internal force values upon completion of the passage construction are within the allowable design limits.