Study on Shearing Characteristics of Circumferential Joint Rebate of Stagger-Jointed Shield Tunnel

At present, the design and construction of shield tunnels often adopt stagger-jointed form with rebate, and improving the mechanical properties of rebate is the key to solving the problem of leakage of tunnel structure and other diseases. This paper aimed at circumferential joint rebate of staggered shield tunnel segment, established the local model of discontinuous contact of three-dimensional solid joint to analyse the influence of rebate and the length and inclined angle of it on shear resistance of joint. The result shows five points: (1) When the segment joint is sheared, the greater the axial force of the joint, the stronger the frictional shear resistance. (2) Setting rebate in joints can reduce the number of dislocations in the stage of rapid development of dislocation and increase the shear resistance of joints. (3) The length of rebate has little influence on the shear strength of joints. (4) The angle of inclined plane of rebate has a great influence on the shear resistance of joint. The smaller the angle of inclined plane, the larger the peak shear force and the corresponding dislocation, while the greater the local stress. (5) When the inclined angle increases, the stress of rebate is more uniform, which can prevent the damage of rebate.