Numerical Simulation Study on the Dynamic Response Characteristics of Adhesive Steel Reinforced Pipe Joints Under Positive Bending Moments

To explore the dynamic response characteristics and failure modes of sticky steel-reinforced segment joints under cyclic loading, a refined finite element analysis model for such joints is developed against the backdrop of a practical urban shield tunnel. This study involves simulating the dynamic characteristics of sticky steel-reinforced segment joints under positive bending moments during cyclic loading, and exploring damage evolution features, failure modes, stiffness degradation, hysteresis energy dissipation characteristics, and ductility deformation capabilities. Results show that during the initial loading stage, the steel plates of the reinforced joint can effectively share the tension borne by the bolts, with the initial failure occurring at the bond between the steel plates. Once extensive delamination of the steel plates occurs, the failure process of the reinforced and unreinforced joints tends to be consistent. During the initial loading stage, the reinforced steel plates significantly enhance the stiffness and bending moment of the segment joint. Even after extensive delamination of the steel plates, the bending moment and stiffness of the reinforced joint remain slightly higher than those of the unreinforced joint. Under positive bending moment cyclic loading, the segment joint exhibits cumulative damage characteristics: with an increase in the number of cycles under the same load level, the joint demonstrates a certain degree of load-carrying capacity degradation. In the initial loading stage, due to the cracking failure of the structural adhesive, the energy dissipation capacity of the reinforced joint is noticeably higher than that of the unreinforced joint. During the later loading stages, the energy dissipation capacity of both reinforced and unreinforced joints increases with the increase in the degree of concrete damage, however, the energy dissipation capacity of reinforced joints is still slightly stronger than that of unreinforced pipe sheet joints.