Spatial Characteristics of Aeolian Sand Transport Affected by Surface Vegetation along the Oshang Railway

Abstract

Blown sand transport plays a pivotal role in determining the optimal placement of sand protection facilities along railways in sandy areas. Surface vegetation cover significantly influences blowing sand activities along the Oshang Railway (from Otog Front Banner to Shanghai-Temple Town). In this study, the spatial characteristics of aeolian sand transport along the railway were derived from field observations conducted at five different locations, each with varying fractional vegetation cover (FVC). The results indicate that sand-transport intensity does not fully correlate with the wind energy environment, primarily due to differences in surface vegetation cover among the observation sites. We utilize the dimensionless ratio Q·g·f/(0.136 × DP·ρa) to represent the sand transport rate (Q), the sand-moving wind frequency (f) and drift potential (DP), exhibiting a negative exponential trend with FVC. Sand transport is effectively restrained when FVC is greater than or equal to 20%. Conversely, when FVC is less than 20%, sand transport intensity exponentially increases with decreasing fractional vegetation cover. After careful analysis, we propose a simple empirical expression that incorporates the influence of both the wind field and fractional vegetation cover to assess sand transport on a flat surface. The study offers valuable insights for designing wind-blown sand protection measures along railways and evaluating wind-blown sand movement on a flat surface affected by vegetation.