Comparative study of the load-bearing and deformation behaviors of metal mesh and polymer thin spray-on liner surface supports in mining roadways

To investigate the differences in load-bearing capacity and deformation control between metal mesh and polymer thin spray-on liners (TSL) for roadway surface support, a study was conducted based on a mining roadway in Yulin, Shaanxi Province, China. Small-scale simulated roadway tests and engineering-scale numerical simulations were combined. Under the same geometric, boundary, and loading conditions, the peak load, strain response, surface displacement, and failure characteristics of the two support systems were compared. The effects of different surface supports on surrounding rock deformation and stress distribution were further analyzed under the same bolt–cable support conditions. The results show that the peak load of the metal mesh specimens was about 70 kN, with a maximum surface displacement of about 0.42 mm. The TSL specimens reached a peak load of about 85 kN, which was 21.4% higher than that of the metal mesh specimens, while the maximum surface displacement decreased by 23.8% to about 0.32 mm. Metal mesh mainly restrains loose rock blocks through tensile resistance, bending, and containment, whereas TSL provides earlier confinement to the shallow surrounding rock through continuous coverage, bonding, and membrane action. Numerical results indicate that, compared with metal mesh support, TSL support reduced the peak sidewall convergence, roof subsidence, and floor heave by 34.1%, 11.0%, and 6.3%, respectively, and slightly reduced the high-stress zone. The results suggest that, under the conditions investigated in this study, TSL has potential advantages in improving surface support performance and reducing shallow surrounding rock deformation. However, its long-term applicability and material safety require further verification through field monitoring and additional tests.