Upper Bound Stability Analysis of Shield Tunnel Face in Nonhomogeneous and Anisotropic Soils

• DOI: 10.1007/s40098-017-0224-z
• Publication Date: 2017-02-14T08:34:41Z
• Authors: Qiao Liang; Cong Yao; Jingshu Xu
• Keywords: Safety factor; Basis (linear algebra)

This paper focuses on the stability of shield tunnel face excavated in nonhomogeneous and anisotropic soils. The models of soil nonhomogeneity and anisotropy are established on basis of existing researches. Two failure mechanisms of tunnel face are constructed to reveal different conditions of face failure. Upper bound analysis is conducted and the analytical solution of supporting pressure is deduced. By virtue of numerical optimization, the upper bound solution of supporting pressure is derived. Parameter analysis shows that both nonhomogeneity and anisotropy of soil mass have great influences on the supporting pressure and corresponding failure mechanism. Besides, the buried depth is also found to be a key factor to the stability of tunnel face.