The construction of new metro stations in close proximity to existing tunnels poses significant engineering challenges due to potential disturbances in soil stability and structural integrity. This study employs a three-dimensional finite-element model to evaluate the impact of adjacent metro-station construction on an operational tunnel, with emphasis on induced structural stresses and deformations. Based on the simulated mechanical response, a safety assessment of the existing tunnel is conducted. Numerical results reveal that excavation and support activities during station construction lead to limited structural stress redistribution and deformation in the adjacent tunnel. Results indicate that station excavation and support installation induce measurable but limited responses in the existing tunnel: peak bending moment rises by 8.7% and peak axial force increases by 5.7%. The maximum displacements observed are 2.1 mm in the vertical direction and 1.6 mm laterally, both substantially below the widely accepted control threshold of 10 mm. The study emphasizes the importance of maintaining design strength margins, implementing targeted reinforcement—particularly to enhance vertical stiffness—and adopting rigorous real-time monitoring coupled with detailed post-construction inspection to safeguard long-term operational safety.
Liu et al. (Tue,) studied this question.