Abstract: The prefabricated joint is a prominent structural feature that distinguishes prefabricated metro stations from traditional cast-in-place stations. To investigate the bending deformation and failure mechanisms of grouted mortise and tenon joints, a comprehensive study is conducted. Experiments are performed to determine the compressive deformation characteristics of the grouting material (modified epoxy resin) and its bonding properties with concrete. Based on these experimental results, a simulation method is developed to model the joint grouting surface contact, incorporating the bond strength and bond failure model. Finally, a finite element numerical model is created and analyzed to evaluate the joint under bending loads. The results reveal the following: (1) The moment-rotation curves of the joint closely align with the experimental data, and the crack distribution patterns observed during bending failure closely match test results. (2) The numerical results, including the development of principal tensile stress, the failure of the grout-concrete bonding relationship, and crack propagation patterns, further reveal the bending deformation mechanism of the grouted mortise and tenon joints. (3) A comparative analysis of three simulation methods for grouting surface contact relationships—bond failure, friction, and tie—demonstrates that using friction or tie contact models leads to an underestimation of the joint′s flexural load-bearing capacity. (4) The findings highlight the importance of refined modeling of the grout-concrete bond relationship in grouted mortise and tenon joints for accurately evaluating their mechanical performance.

Key words: metro station, prefabricated assembly, grouted mortise-tenon joint, bond interface, bending performance, numerical simulation