Numerical Simulations and Wind Tunnel Experiments to Optimize the Parameters of the Second Sand Fence and Prevent Sand Accumulation on the Subgrade of a Desert Railway

Abstract

Wind-blown sand significantly affects the construction and safe operation of railways in desert regions. The performance of a wind-blown-sand prevention system with different structural parameters and sand accumulation around the railway subgrade was analyzed in this study. The optimum porosity and opening type of a second sand fence were assessed via wind tunnel experiments and numerical simulations. The results showed that the subgrade intercepted some sand and reduced sand accumulation on the track surface, and the interception rate was 29.70%. The wind-blown-sand prevention efficiency of the subgrade was 88.55%. Moreover, the lower the porosity of the second sand fence, the lower the sand velocity on the windward side and the higher the sand accumulation. The porosities of the first and second sand fences should be 30% and 20%, respectively, to maximize the sand accumulation between the fences. When the second sand fence had horizontal openings, most of the sand accumulated near the surface (within 20 cm) on the leeward side and on the straw checkerboard barrier, and the maximum wind-blown-sand prevention efficiency was 97.16%. When the second sand fence had vertical openings, the efficiency was 93.60%, and the sand accumulation on the leeward side and the straw checkerboard barrier was reduced. As the fence height increased (above 20 cm), the sand prevention efficiency of both approaches increased. The research results can provide guidance for the formulation and optimization of sand prevention measures for railways and highways in deserts.