UAV photogrammetry for evaluating sand-blocking performance and accumulation dynamics of railway sand barriers in the Gobi High-Wind Corridor

Unmanned aerial vehicle (UAV) photogrammetry, an emerging spatial information measurement technology, enables rapid and efficient acquisition of high-resolution surface textures and can generate orthophotos and three-dimensional (3D) models that accurately represent the spatial characteristics of the Earth's surface. Based on this technology, this study monitored and analyzed sand accumulation characteristics around different sand barrier types in the Yandun windy area along the Lanzhou-Xinjiang high-speed railway. The formation mechanisms of sand accumulation patterns and the protective performance of high vertical sand barriers were elucidated. Results show that wind-blown sand creates distinct deposition patterns around the barriers, characterized by shorter accumulation on the windward side and significantly longer accumulation on the leeward side, with a windward-to-leeward length ratio ranging from 0.1 to 0.15. The maximum sand accumulation height occurs on the leeward side within 0.5H to 1.5H from the barrier (where H is the barrier height). Moreover, the vertical sand accumulation rate on the leeward side is substantially higher than that on the windward side. Specifically, the maximum vertical sand accumulation rate for the high-density polyethylene (HDPE) mesh sand barrier on the leeward side reaches 0.0697 cm/d, which is 1.2-fold and 1.6-fold greater than the corresponding maximum rates for the slanted panel and vertical inserted panel sand barriers, respectively. The total sand accumulation volume on both sides of the barriers exhibits a linear growth trend over time. The sand accumulation growth rates of the HDPE mesh and slanted panel barriers are significantly higher than those of the vertical inserted panel barrier, indicating superior protective performance. Considering the balance between sand-blocking efficiency and cost-effectiveness, HDPE mesh sand barriers are recommended as the priority choice for constructing the forefront sand-blocking belt in high-wind Gobi zones, with a suggested sand-clearing and maintenance cycle of 5–6 years. These findings provide comprehensive technical support for subsequent design refinements and the implementation of similar engineering projects in comparable regions.