Wind dynamic environment, sand material transport law and prevention strategies of Sichuan Tibet Railway.

The Sichuan-Tibet Railway passes through windy and sandy areas in the river valleys of the southern Tibetan Plateau. Currently, the wind dynamic environment, sand material characteristics, and transport laws along the route are not well understood, hindering targeted sand control efforts. Through installing meteorological stations in the four wind-sand hazard sections along the route, respectively, key factors such as wind speed, wind direction and humidity that affect the dynamic process of wind-sand were observed, and sand samples were collected for particle size analysis. It is found that the average wind speed, sand-moving wind frequency, sand drift potential (DP), resultant drift potential (RDP), maximum possible sand transport quantity (Q), and resultant maximum possible sand transport quantity (RQ) are highest in spring (February to April). The predominant wind directions throughout the year are E, SSE, and ENE. Overall, the railway line is characterized by a low wind energy environment (DP ≤ 200 VU), and the directional variability index is moderate (0.3 < RDP/DP < 0.8). Sand materials are primarily fine sand (2-3 Φ) and medium sand (1-2 Φ). The key period for wind-sand hazard prevention and control is spring. The wind-sand prevention and control of the railway should focus on blocking (sand) and consolidating (sand), using external barriers and internal consolidation (distant blocking and near consolidation). Simultaneously, sand-fixing vegetation should be cultivated to establish a comprehensive protection system. To ensure the smooth operation of railway and the safety of train operation. The findings provide a scientific basis for the prevention and control of wind-sand hazards along the Sichuan-Tibet Railway.