Study on Earthquake Behavior Characteristics of Longitudinal Joint of Shield Tunnel Based on Submodeling Method

In order to clarify the stress characteristics of longitudinal joint of shield tunnel under earthquake, the submodel method is used to set up the joint refinement model based on actual engineering. Detailed deformation characteristics of longitudinal joint under different excitation directions are studied, and then the failure test is conducted to verify numerical results. The results of numerical and failure test show that when the seismic load is excited along the longitudinal and transverse directions of the tunnel, the stress characteristics of the tension risk area in the two working conditions are the same. The maximum principal stress concentration region of both tow conditions appears in the hand hole, the longitudinal joint surface and around the sleeve. The maximum principal stress extreme value appears around the sleeve, and the joint is more dangerous under longitudinal excitation. In the failure test, when the segment structure is broken, the bolt is not yet yielded, and the largest failure region appears on the joint surface adjacent to the outer surface of the segment, with slight crack occurs in the area of the hand hole. The concrete strain on the inner and outer surfaces is relatively small, and the internal surface on the hand hole side has a large compressive strain, while the outer surface of the sleeve side has a large tensile strain. The research results provide reference and learning for further revealing the stress characteristics of the longitudinal joint as well as the damage form of shield tunnel. © 2022, Department of Journal of the China Railway Society. All right reserved.