Wind Tunnel Test about the Effect of Vegetation Sand-barrier on Wind-blown Sand Flow near Ground Surface

tively common that road suffers from the impact of wind erosion and sand-burying.Especially,shifting sand movement leads to sand hazard to highway and traffic jam.Furthermore,the traffic and its safety are threatened.At present,the vegetation sand-barrier has become as an effective way for preventing wind-blown sand disasters in some areas,and it will be widely applied in the future,but its mechanism of preventing wind-blown sand disasters is not identified yet.In this paper,a wind tunnel test is made to simulate wind prevention and sand fixation benefits of the vegetation sand-barrier with coverages of 10%,15%,20%,30%,40% and 60%.The testing wind velocities are 6 m/s,8 m/s and 11 m/s.The characteristics of wind speed profile and structure of drifting sand flux,and the effect of sand fixation are revealed.The experimental results are as follows:(1) Total accumulated sand amount is gradually reduced with increasing the coverage,sand particles in wind-blown sand flow are distributed in a certain height range,but the distribution height is in a descending trend with increasing the coverage;(2) Plant luxuriance affects obviously the wind-blown sand flow structure.The higher the coverage is,the more concentrative the sand accumulation in the lower height will be.The coverage is not the only index resulting in the reduction of sand accumulation to zero;(3) Occurrence of wind erosion is not only related to vegetation,but also to the porosity of vegetation,height of shelter forest,etc.