Efficiency of Leeward-Side Sand-Control Measures for High Embankments in Desert Regions

Wind-blown sand threatens railway safety in arid regions. Existing measures mainly protect the windward side and cannot fully prevent particles from crossing the embankment. These particles can be re-entrained by leeward flows and redeposited on the track. This study combines wind tunnel experiments, large eddy simulation, and field observations to examine leeward-side protection for a high railway embankment. Three configurations are tested: no protection, baffles on the leeward slope, and a checkerboard barrier at the slope toe. The results show clear differences in flow structure and sand transport. Without protection, flow reattaches within 2–3 H (H is the height of the embankment) and near-surface velocity reaches 10–11 m/s. With baffles, reattachment shifts to 3–4 H and velocity decreases to 7–9 m/s. With a checkerboard barrier, reattachment is delayed to 4–5 H and velocity reduces to 4–6 m/s, forming a stable low-velocity zone. Surface shear stress decreases from 0.4–0.5 Pa to 0–0.2 Pa, and particle concentration near the shoulder drops by about one order of magnitude. Particle transport is weakened and deposition concentrates at the slope toe. Subgrade sand accumulation decreases from 350–480 g/min to 170–250 g/min. Field results confirm these trends. The checkerboard barrier effectively limits sand movement and improves deposition stability. The proposed leeward-side protection measures can effectively reduce sand accumulation on railway infrastructure, thereby improving the long-term operational safety, resilience, and sustainability of railways in desert environments under increasing wind–sand hazards.