Reliability Analysis of Seismic Stability of Shield Tunnel Face under Multiple Correlated Failure Modes

In this paper, the seismic stability of shield tunnel face under multiple correlated failure modes is studied by combining the upper bound theorem of limit analysis with the response surface method. The pseudo-static method is employed to research the influence of seismic forces on the assessment of active and passive failure of shield tunnel face. The critical collapse pressure and blowout pressure of tunnel face are solved by the upper bound method. Furthermore, the reliability model of shield tunnel face is established in terms of these two limit states, and the range of supporting pressure to ensure the stability of tunnel face is obtained by the response surface method. Comparison of the solutions of this paper with existing results verifies the present method. The research shows that, the safe range of supporting pressure of tunnel face based on the reliability model of multiple correlated failure modes is more reasonable and effective. The soil shear strength and seismic force exert an obvious effect on the stability of tunnel face. In addition, the dispersion of random variables reduces the stability of shield tunnel face. This work can provide some guidance for the anti-seismic design of tunnel face in earthquake-prone regions.