Abstract: The authors investigate the influence of various construction parameters on tunnel structure integrity and surrounding geological stability during the mechanical cross-passage excavation. A global sensitivity analysis based on the Sobol method is employed in conjunction with a finite element numerical model that simulates tunnel structure behavior and auxiliary construction facilities. Numerical simulations are conducted throughout the entire construction process, and the results are validated against field monitoring data. Key findings include: (1) During lateral excavation through the main tunnel for cross-passage, the maximum displacement of the main tunnel increases by approximately 34% compared to the pre-construction state, while maximum stress levels rise by 15.5%, and interfacial stresses increases by 5%－8%. Stresses within the internal support system range from －12 MPa to 40 MPa. Additionally, structural strains and stresses exhibit a degree of rebound or reduction after construction completion. (2) Significant stress and deformation variations are observed near the cutting ring opening, with principal stress Ⅲ distributions forming spindle-shaped geometries along the inside and outer surfaces of the cutting ring cross-section. (3) The deformation displacement curves from numerical simulations are consistent with field monitoring data, closely matching average trend curves and demonstrating similar variation tendencies, thereby validating the accuracy of the numerical model. (4) Sensitivity analysis indicates varying rankings of construction parameters′ influence on stress and deformation.  Key influencing parameters include chamber pressure, propulsion force, torque, and prestress in the internal support frame. Among these, chamber pressure is identified as the most sensitive parameter affecting bolt axial forces, which remained within a controllable range.

Key words: shield method, cross-passage, numerical simulation, displacement monitoring, construction parameters, global sensitivity analysis