Abstract:
The ring joints of shield tunnels have obvious nonlinear mechanical characteristics, and it is difficult to analyze the longitudinal deformation of tunnels reasonably to simulate the response of the stress and deformation. In order to solve this problem, this paper proposes a simple and practical model for the analysis of joints between rings, that is, the contact surface element that can transmit pressure but not tension is used to simulate the ring-to-ring contact, and the beam element based on the embedded beam generalized displacement method is used to simulate bolts. The nonlinear contact state at the joint between the rings and the axial stiffness and shear stiffness of the joint bolts are considered, and it is suitable for all kinds of bolt shapes between the rings (straight bolts, bent bolts or oblique bolts). A calculation example is used to compare the calculation results of the finite element and the theoretical analysis model to verify the accuracy of the model. The model is applied to the longitudinal deformation analysis of shield tunnels crossing the fault fracture zone in an actual project. The results show that the water conveyance shield tunnel is stable in homogeneous bedrock; and the deformation of the lining ring joints in the fault fracture zone and the bolt stress increase significantly, but are within the design control range. The model can provide a certain reference for engineering safety construction and operation.