土壤凝结剂沙障防沙机理的风洞模拟实验研究

模型按 1 :1 0比例设计 ,在 7m/s、1 5 m/s和 2 0 m/s的实验风速下 ,对不同浓度土壤凝结剂处理的沙障模型进行风洞实验 ,测定其蚀积状况。实验结果表明 :抗风蚀强度以 40 %浓度处理的固沙模型最强 ,2 0 %最弱 ,但 30 %浓度防风蚀效果较为实用。积沙状况与浓度关系不明显 ,水平放置与坡面 ( 30°)放置时均以 1× 1 m规格的沙障积沙最多 ,1 .5× 1 .5 cm次之 ,2×2 cm最差。风速在障前受阻减弱 ,而后沿流速方向在沙障间逐渐增大 ,在第二格上方障埂处出现最大值 ,障后逐渐减速 ,直至障高 1 0倍处趋于稳定。障前、障后风速降低是引起障前、障后积沙的主要原因 ,也是土壤凝结剂沙障的防沙机理。

Wind Tunnel Test on Sand-preventing Mechanism of Soil Coagulant Sand-barrier

The model was designed with 1:10 scale, and the testing wind velocity consist of 7.0m/s,15.0m/s and 20m/s. The erosion-deposition characteristic of soil coagulant sand-barrier with different concentration treatment was measured under wind tunnel test. The results were as follows: The biggest intensity of erosion resistance was sand-fixing sampling of 40% concentration , and the treatment of 20% was the worst, but treatment of 30% was more practical. The relation between the deposition feature and concentration was not obvious. The sand-barrier of the most deposition was 1×1m scale among different scales sand-barrier either in horizon or in 30° slope, the more was 1.5×1.5m, and 2×2m was the least. The wind speed decreased gradually resulted from the stopping function of the barriers before and after the barriers, Then the wind speeds up gradually when it flowed to the barriers, and reaches the maximum over the middle checker(second checker) board, and then decreased.The flow trended to stable after 10 times sand-barriers height. The wind speed decrease resulted to the sands deposition in front of and behind barriers, and was the sand-preventing mechanism of the soil coagulant checker barriers.