Analytical and Numerical Study on the Performance of the Curved Surface of a Circular Tunnel Reinforced with CFRP

Pasting carbon fiber reinforced polymer (CFRP) has become an effective method to reinforce the circular tunnel. For this reinforcement method, the mechanical performance of the curved substrate is important to keep the coordinated deformation of CFRP and the lining concrete. To investigate the effect of interface curvature on the stresses of the reinforced interface, an analytical model is proposed for the curved reinforced interface with the consideration of the interface bond–slip relationship. Additionally, a 3D numerical model is established to further investigate the effects of some important parameters (CFRP’s layer, length, elastic modulus, thickness and the adhesive’s elastic modulus, thickness) on the reinforced interface stresses. The results reveal that the stress state of the curved reinforced interface is more complex than that of the plane reinforced interface. With decreasing the radius of the curved reinforced interface, the interface radial stresses are increased significantly, while the circumferential stresses hardly change. For the adhesive, decreasing the elastic modulus and thickness of the adhesive layer can significantly improve the stress state of the reinforced interface. For the CFRP, decreasing the thickness, elastic modulus and layer number of CFRP is conducive to full utilization of materials and long-term combined work of the concrete and CFRP.

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