Objective To investigate the assembly and load-bearing mechanical performance of a novel automatic ring connector for shield segments, it is necessary to carry out pull-out tests and numerical simulations on the ring joints of shield segments equipped with the novel automatic connectors.

Method Laboratory insertion and extraction tests and numerical simulations are carried out on a novel automatic ring connector for shield segments with self-adaptive functionality. Key mechanical properties such as pull-out bearing capacity, pull-out stiffness, and stress distribution patterns are obtained, revealing the mechanical transmission mechanism and construction adaptability characteristics.

Result & Conclusion  Experimental results show that the maximum insertion force of the connector is 25.5 kN, with a pull-out bearing capacity of 536.8 kN and a longitudinal pull-out stiffness of 51.65 MN/m. During the elastic stage, the joint opening could be controlled within 6 mm. The welded position of the anchor bars on the male connector is identified as a mechanically weak point. The joint surface of the male connector exhibits extensive spalling and radial cracks around the connecting components, while that of the female connector only shows peripheral circumferential cracks. Numerical simulation results show that the concrete in both the male and female connectors experiences tensile yielding around the front section of the anchor bars and in the gaps at the rear section. The concrete surrounding the embedded connecting components in the female connector undergoes shear failure, whereas the concrete at the welded anchor bar root of the male connector and its surrounding area exhibits failure. The stress variation trend of the anchor bars with increasing pull-out force is consistent with the numerical simulations and experimental results, but the anchorage structure of the male connector is weaker than that of the female connector.