直压立式纱网沙障对近地表输沙量及风速的影响

评价直压立式纱网沙障对流动沙地的固沙效果是其应用的前提。采用阶梯式集沙仪和HOBO风速仪野外测定了纱网沙障的输沙量及风速变化。结果表明:与对照相比,设置纱网沙障后,0~10 cm或0~20 cm高度范围内,带宽2、3、4、5 m带状沙障输沙量分别降低91.4%或89.7%、97.0%或96.4%、98.1%或96.7%、85.9%或84.2%;而2 m×2 m、3 m×3 m、 4 m×4 m、5 m×5 m网格沙障输沙量分别降低92.1%或91.2%、70.4%或65.6%、65.3%或65.2%、39.9%或30.0%。与对照相比,10、30、50 cm高度,带宽2、3、4 m带状沙障平均降低风速分别为26.7%、17.3%、11.8%,2 m×2 m、3 m×3 m、4 m×4 m、5 m×5 m网格沙障平均降低风速分别为55.3%、30.4%、23.0%。综合考虑,设置带宽3~4 m带状或网格纱网沙障能够满足工程固沙减少风沙危害的需求。

Influence of gauze sand barrier on sediment transport and wind speed near surface

It is a prerequisite for its application to evaluate the sand-fixing effect of gauze sand barriers in moving sandy land. The sediment discharge and change of wind speed of gauze sand barrier have been measured with step-type sand collector and HOBO anemometer in field. The results show that after establishing gauze sand barrier, compared with the control, the sediment discharge of 2 m, 3 m, 4 m and 5 m strip sand barriers in height range of 0-10 cm or 0-20 cm have decreased by 91.4% or 89.7%, 97.0% or 96.4%, 98.1% or 96.7%, 85.9% or 84.2%, respectively. And the sediment discharge of 2 m, 3 m, 4 m and 5 m grid sand barriers in height range of 0-10 cm or 0-20 cm have decreased by 92.1% or 91.2%, 70.4% or 65.6%, 65.3% or 65.2%, 39.9% or 30.0%, respectively. Compared with the control, at the height of 10 cm, 30 cm and 50 cm, 2-4 m strip sand barrier can averagely reduce the wind speed by 26.7%, 17.3% and 11.8%, and 2-5 m grid sand barrier can averagely reduce the wind speed by 55.3%, 30.4% and 23.0%. By comprehensive consideration, it can meet the needs of reducing the sand damage with sand-fixation engineering to establish 3-4 m strip or grid gauze sand barrier.