3D Printed Concrete Tunnel Lining (2025-06)¶

As a representative technology of Industry 4.0, additive manufacturing demonstrates significant potential in innovative tunnel lining structures. However, current research on the mechanical properties of 3D-printed concrete tunnel linings remains limited. This study systematically investigates the compressive and flexural performance of 3D-printed concrete tunnel linings fabricated through curved-path and linear-path printing strategies. A novel stress-difference based method is proposed to divide the compression process into five distinct phases: pore compaction, linear elasticity, yielding, failure, and residual stages. The anisotropic compressive strength characteristics under X, Y, and Z loading directions are analyzed, with particular emphasis on the influence of weak interfacial regions on mechanical behavior. The experimental results show that compared with linear printed samples, curved printed samples exhibit significantly superior compressive strength, while when loaded in the Z direction, they show significantly enhanced bending resistance compared to samples in the X and Y directions. This research elucidates the anisotropic mechanical properties of 3D-printed concrete and provides valuable insights for optimizing printing path strategies to enhance structural performance and mitigate compressive strength anisotropy.