Development of a laboratory-scale apparatus and experimental investigation of fluid property effects on pipe wear in slurry shield TBM operations.

Managing pipeline wear is critical for maintaining excavation efficiency during slurry shield tunnel boring machine (TBM) operations. Yet, the effects of carrier fluid properties on pipe wear in slurries containing coarse particles remain insufficiently understood. To address this gap, this study developed a laboratory-scale test apparatus to simulate slurry flow in the discharge pipelines of a slurry shield TBM, focusing on the influence of carrier fluid viscosity and density on pipe wear. Crushed granite fragments with a uniform size distribution were employed as erodent particles. Pipe wear in both horizontal straight and bending sections was assessed by measuring changes in pipe weights. Results showed that, at higher fluid viscosities with constant density, pipe wear in the straight section decreased, while wear in the bending section remained largely unchanged. In contrast, denser fluids led to more pronounced wear in both sections. Further analysis of wall thickness reduction in the bending sections revealed that the impingement behavior of erodent particles varied with carrier fluid density. These findings provide valuable insights into pipeline wear mechanisms and emphasize the importance of accounting for slurry characteristics when developing effective wear management strategies for slurry shield TBM operations.