Experimental and Numerical Study on the Impact of Multi-Line TBM Tunneling in Fractured Zones on Building Deformation

Tunneling in fractured zones significantly affects surface and building deformation. This paper investigates the deformation of overlying buildings and the surrounding ground induced by multi-line TBM tunneling in fractured zones of the Qingdao Metro, combining a 3D physical model test, numerical simulations, and field monitoring to analyze the evolution of settlement and structural responses. The results show that settlement induced by TBM excavation peaks at the center and diminishes laterally, with amplified differential settlement and building torsion near fractured zones. Comparative analyses of reinforcement strategies indicate that crown grouting is the most effective in reducing deformation. Sensitivity analysis further indicates that tunnel depth, grouting pressure, and building–tunnel relative position are the dominant factors influencing building settlement. The findings provide practical guidance for similar projects in complex geological conditions and contribute to deformation control in underground works.