Analysis and reinforcement design of power concentrated joints in steel arch splicing mechanisms for tunnel boring machines.

To address the challenges of low efficiency and high safety risks in manual steel arch installation during Tunnel Boring Machine (TBM) construction, this study proposes an innovative steel arch splicing mechanism. By employing power-concentrated joint analysis and closed-loop reinforcement design, the mechanism demonstrates significantly enhanced dynamic performance and load-bearing capacity. The research first introduces a novel bolt-free steel arch joint structure that enables rapid automatic splicing through a self-locking mechanism. Subsequently, two power-concentrated joints in the mechanism are identified using unit power concentration metrics, and optimized through hydraulic-driven closed-loop structural designs, effectively improving both structural stiffness and power transmission efficiency. Prototype testing results show that the optimized mechanism achieves an impressive load-to-weight ratio of 1.19, with splicing efficiency 4-8 times higher than manual operations, while maintaining stable and reliable grasping and docking performance. This work presents an efficient and reliable solution for automated steel arch splicing in heavy-duty construction environments, offering substantial engineering application value.