A real-life stability model for a large shield-driven tunnel in heterogeneous soft soils
1. Department of Civil Engineering, Shanghai Institute of Technology, Shanghai 201418, China; 2. Department of Geotechnical Engineering, College of Civil Engineering, Tongji University, Shanghai 200092, China; 3. Institute of Applied Geosciences, Graz University of Technology, Graz 8010, Austria
The current models that have been published to date only allow for homogeneous soil at the tunnel face. This paper presents a real-life face stability model to determine the minimal pressure needed at the tunnel face for a large shield-driven tunnel in heterogeneous soft soils. It is found that the influence of multilayered soil boundaries is significant, especially for the mixed-layer (e.g., sand and clay) soils. The suggested M-M model is developed by considering the influence of the heterogeneity of the soil on the angle of slip and the minimal support pressure. Comparisons of the solutions in mixed-layer soils are conducted, and the effects of the involved parameters for a large, multilayered, shield-driven tunnel are also investigated.