Stability analysis of large slurry shield-driven tunnel in soft clay

• Published in: Tunnelling and underground space technology Vol. 24; no. 4; pp. 472 - 481
• Main Authors: Li, Y., Emeriault, F., Kastner, R., Zhang, Z.X.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.07.2009; Elsevier
• Subjects: Applied sciences; Buildings. Public works; Computation methods. Tables. Charts; Exact sciences and technology; Face stability; Global stability; Local stability; Partial failure; Slurry shield-driven tunnel; Structural analysis. Stresses; Tunnels, galleries; Upper bound theory; Asia; China; China, People's Rep., Changjiang R; China, People's Rep., Shanghai; Face stability; Slurry shield-driven tunnel; Global stability; Upper bound theory; Local stability; Partial failure; Clay; Structural stability; Mechanism analysis; Theoretical study; Soft soil; Case study; Upper bound; Numerical analysis; Analysis method; Tunnel driving; Numerical simulation; Damaging
• ISSN: 0886-7798; 1878-4364
• DOI: 10.1016/j.tust.2008.10.007

The face stability of large slurry shield-driven tunnels is investigated by an upper bound approach in limit analysis and three-dimensional numerical modelling for the Shanghai Yangtze River Tunnel. Both the local failure and global failure in collapse and blow-out are studied. Firstly, the upper bound solution for local stability is presented, taking into account the gradient of slurry pressure. The maximum tunnel diameters for given site conditions could be determined by this solution. Then, the progressive global stability mechanism is studied using a multiblock model of upper bound theorem. The analysis shows that it is necessary to take into account the partial failure in large size slurry shield-driven tunnels, especially in the case of blow-out. The global blow-out of the partial upper part of the tunnel face occurs when the slurry pressure is too great; while the global collapse of the whole tunnel face occurs when the slurry pressure is too small. The failure mechanisms and critical slurry pressures obtained from both the multiblock model to numerical simulations are compared with each other.