Abstract: The study examines a shield-launching section in Baoding City and develops a three-dimensional stratigraphic numerical model using the finite-element platform ABAQUS. The model captures the evolution of vertical surface displacement during shield tunneling, and the simulated results show strong agreement with on-site monitoring data. Building on this validated model, a parametric sensitivity analysis is performed by increasing and decreasing the unit weight, elastic modulus, Poisson’s ratio, internal friction angle, and cohesion of the reinforced soil by ±20%. The corresponding changes in vertical surface displacement are then evaluated. The results indicate that variations in cohesion and Poisson’s ratio have minimal influence on surface deformation, whereas internal friction angle, elastic modulus, and unit weight exert significant effects. The relative sensitivity ranking is: internal friction angle > elastic modulus > unit weight. Based on these findings, an optimal parameter range for soil reinforcement is proposed. When the internal friction angle is 28°~32°, the elastic modulus is 95~105 MPa, and the unit weight is approximately 20 kN/m³, the excavation process demonstrates improved deformation control and enhanced construction safety. These results provide a useful reference for shield tunneling design in similar geological conditions.

Key words: Shielded Tunneling, Soil Reinforcement, Numerical Simulation, Parameter Influence