Impact of missing insert positions on the sand-control performance of slant-insert sand-blocking walls

Wind-blown sand accumulation on railway tracks (sand hazards) threatens transportation safety. Slant-insert sand-blocking walls are effective countermeasures, yet their performance under realistic, damaged conditions remains poorly understood. This study investigates the impact of missing insert positions on the sand-control performance of such walls by integrating field monitoring and computational fluid dynamics simulations. A validated three-dimensional Reynolds-averaged Navier–Stokes model with the shear stress transport k–ω turbulence model was employed to simulate seven scenarios (intact wall and six damage cases with two adjacent inserts missing from bottom to top). Results reveal that insert loss degrades performance, but the severity is critically dependent on the missing location. The loss of bottom inserts is most detrimental: it reduces the sand accumulation zone area by 36.8% and the recirculation bubble area by 89.4%, disrupts the leeward vortex structure, induces near-ground speed-up (indicating a local venturi effect), and triggers intense forward erosion (erosion intensity increased by 573%). In contrast, damage at higher positions results in progressively lesser degradation. The findings underscore that structural integrity, especially at the base, is paramount. This research provides a quantitative framework for assessing the long-term serviceability of sand barriers and emphasizes the priority of maintaining bottom inserts in design and maintenance strategies to ensure railway protection.