Study on the mechanical behaviour of assembly prestressed reinforced structure and shield lining composite system

The internal reinforcement technology is an important method for controlling deformation of shield tunnels. However, existing internal reinforcement technologies fail to balance strengthening efficiency with economic feasibility, which also hinder the detection of cracks and water leakage. This paper innovatively proposes a design approach of assembly prestressed reinforced structure (APRS) to solve the existing problems. A full-size numerical model of APRS and shield lining composite system is established by using ABAQUS. In the selection of prestressed types, the reinforcement efficiency is the highest when the vault member is set to tensile stress and the arch waist member is set to compressive stress. Regarding the determination of prestressing magnitude, strengthening efficiency is proportional to the prestressing value, and the optimal limit of prestress setting is 50 MPa. Moreover, strengthening efficiency of unit steel quantity of the APRS is 2.2 times that of the steel bonding reinforcement structure, demonstrating superior economic efficiency.