Longitudinal Analysis Model of Shield Tunnel Considering Contact Nonlinearity and Its Application

Abstract:

The contact state between the shield tunnel rings is related to the internal force. The traditional shield tunnel structure analysis model cannot consider the contact nonlinearity under the combined action of axial force， shear force， and bending moment. Therefore， this paper proposes a shield tunnel longitudinal analysis model considering the nonlinear contact under the combined action of axial force， shear force， and bending moment. This analysis method is used to analyze the mechanical behavior of the shield tunnel crossing a creeping fault in Shantou Bay. It is found that when the longitudinal joint transmits axial force， shear force， and bending moment at the same time， its force transmission effect can be equivalent to the beam considering the reduction of axial and bending stiffness， and its reduction coefficient is related to the displacement eccentricity. The mechanical analysis of the shield tunnel under creeping load shows that the contact nonlinear longitudinal joint has a great influence on the internal force of the structure， and ignoring the influence of nonlinearity may cause more than 1.4 to 3.3 times of internal force difference. The research results in this paper can be used to analyze the longitudinal mechanical behavior of shield tunnels under complex loads such as creeping fault dislocation.

Key words:shield tunnel;longitudinal nonlinear analysis;fault creep