Study on Possibility of Shield Machine Cutting Through Steel-Reinforced Concrete Diaphragm Wall of Existing Structure

With the rapid expansion of urban transportation networks, new metro tunnels frequently cut through existing structures’ diaphragm walls by using the shield machine. Such intrusions induce dynamic disturbances that pose significant risks to adjacent structures. This study employs Suzhou Metro Line 8 as a case study to evaluate the safety of existing metro stations during shield tunneling, specifically examining deformation characteristics induced by varying tunneling parameters. A three-dimensional numerical model is developed to assess structural responses, with simulation accuracy rigorously validated against field measurements. Results reveal that the transverse influence zone of the base slab extends approximately 2.5 times the tunnel diameter. Diaphragm wall exhibits horizontal deformation opposite the tunneling direction, while the maximum lateral deformation of adjacent station walls reaches 2.49 mm. Concurrently, a slight uplift manifests at the base slab center with a peak value of 2.54 mm. All obtained structural deformations remain well below the permission value of 5 mm, with observed maxima constituting only 50% of this safety threshold. This substantial deformation margin significantly mitigates construction hazards, promoting the sustainable development of underground space.