Improvement of sand control system in longitudinal slope section of desert highway

To address the inadequate protection performance of conventional linear sand barriers on longitudinal slope sections of desert highways, this study proposes a semi-honeycomb sand fence with enhanced anti-overturning capability. The novel design increases the effective interaction area with wind-sand flow, thereby improving sand interception efficiency. Additionally, its geometric configuration induces transverse disturbed airflow, which effectively reduces wind velocity in the prevailing wind direction. To evaluate its sand-control performance, a three-dimensional CFD numerical model was developed, incorporating dune terrain, embankment geometry, and an integrated sand-control system. Comparative analyses were conducted on flow field structure, horizontal wind speed attenuation, and sediment distribution characteristics. The results indicate that: (1) The semi-honeycomb barrier achieves the lowest wind speed at the first fence line, with values at 0.1 m and 0.3 m heights reduced to 20.0% and 15.2% of the incoming wind speed, respectively. Downstream of the second fence, wind speed exhibits minor fluctuations and remains consistently low, with an overall expansion of the low-velocity zone. (2) Wind speed attenuation between the first and second fences reaches 84%–96% for both barrier types, showing negligible differences. However, between the second and third fences, and between the third fence and the high vertical large-grid barrier, the semi-honeycomb type achieves average attenuation rates of 92.6% and 77.6%—representing increases of 10.7% and 6.5%, respectively, over the linear barrier. (3) Sediment thickness at corresponding sections measures 0.29 m, 0.21 m, and 0.12 m, which are 16.0%, 75.0%, and 71.4% greater than those of the linear barrier. (4) The sand accumulation area at the windward toe of the longitudinal slope embankment is reduced to 313.3 m², corresponding to a 75.6% decrease relative to the linear barrier. Moreover, severe sedimentation on the embankment crest and leeward toe is entirely eliminated. These findings demonstrate that the semihoneycomb sand fence offers substantially improved sand protection performance on sloped highway sections, with significant implications for desert road engineering.