Experimental Research on Bending and Shear Resistance of Concrete Segment Joints in Shield Tunnels

The Joint of eonerete tunnel Segments is simultaneously subjeeted to the combined action of axial force, bending moment, and shear force. In order to fully understand the mechanical Performance of the concrete segment Joint un-der different external forces, three sets of tests, including ultimate bearing capacity, ultimate bending moment, and shear tests were designed according to the research characteristics. Subsequently, considering the working conditions of the concrete segment joints with or without oblique bolts, the experimental data of the compressive zone height, maxi-mum opening width, and opening angle of the Joint were analyzed from the perspective of the relationship between axial force and ultimate bending moment. Finally, three comparative test methods, including oblique bolt reverse shear, oblique holt forward shear, and no oblique bolt shear, were used to analyze the failure State of the segment joints and the relative displacement of the joints. The study shows that the compressive zone height and ultimate bending moment of the concrete segment joints with or without oblique bolts both show a linear increase with the increase of axial force, while the maximum opening width and opening angle both show a linear decrease with the increase of axial force. For the segment Joint with oblique bolt connections, the relative displacement curve shows a platform segment, and the platform segment under forward shear is significantly longer than that under reverse shear. Through the comparative study of the forward shear and reverse shear failure of the segment joints, the macroscopic deformation law of the bending and shear resistance of the Joint can be comprehensively revealed. The research results can provide reference for the rational selection of shield tunnel segment Joint construction. © 2024 Science Press. All rights reserved.