Abstract: To investigate the radial shear along the shear direction of the circumferential joint in shield tunnels, a radial shear stiffness calculation model based on concaveconvex tenons and diagonal bolts is established. The development of radial shear along the shear direction in the circumferential joint is analyzed in four stages: static friction, bolt anchoring, bolt bending, and concaveconvex tenon occlusion. The mechanical characteristics and main components of shear stiffness of the circumferential joint in each stage are analyzed using an analytical method. By comparing experimental data with theoretical model results, it is found that: The differences in bolt assembly methods and deformation mechanisms of the structure lead to differences between the theoretical model and test results； During the deformation stage, the results are similar, indicating that the calculation model is capable of accurately describing the shear characteristics of the circumferential joint in the shear process. The experimental data of the loading test of the tenoned segment is compared with the theoretical model. The results indicate that when the longitudinal force reaches 2 000 kN, the experimental results of the shear stiffness of concaveconvex tenon are close to the theoretical model calculation results, which indicates that the theoretical model can accurately describe the mechanical behavior of tenons in the process of shearing under the condition of large longitudinal force.

Key words: shield tunnel, concaveconvex tenon, diagonal bolt, circumferential joint, longitudinal shear stiffness