PLA沙障的风沙流颗粒分布特征

Particle Distribution Characteristics of Aeolian Sand Flow in PLA Sand Barrier

聚乳酸纤维(PLA)作为一种新型固沙材料,为了解不同规格PLA沙障内风沙流不同粒级沙物质的垂直分布规律,本文以沙障前裸沙丘、1.5m×1.5m和1m×1m规格PLA沙障为研究对象,通过野外观测和室内实验的方法,对风沙流中不同粒级沙物质的垂直空间分布特征进行分析。结果表明:0~30cm高度内研究区、1.5m×1.5m PLA沙障和1m×1mPLA沙障输沙量分别占总输沙量的96.6%、87.78%和86.96%;两种规格PLA沙障内输沙率随高度呈幂函数递减,研究区内输沙率随高度呈对数函数递减;各高度层输沙率的大小为研究区】1.5m×1.5mPLA沙障】1m×1mPLA沙障;两种规格PLA沙障和研究区气流中不同粒级沙物质在0~10cm内随着高度的增加,细沙含量呈上升趋势,极细沙、中沙和粗沙含量呈下降趋势;在10~90cm内中粉粒和极细沙量呈上升趋势,细沙、中沙和粗沙含量呈下降趋势;当风沙进入PLA沙障后,粗沙和中沙含量减少,极细沙和细沙含量增多。PLA沙障的设置能显著改变风沙流中沙物质的机械组成,有效阻拦风沙流中的沙粒,1m×1m规格比1.5m×1.5m规格PLA沙障的防风固沙效果显著。

Polylactic acid fiber (PLA) is a new type of sand fixing material. In order to understand the vertical distribution rule of different sand particles in the windblown sand flow in different specifications of PLA sand barriers, this paper takes the bare sand dunes in front of the sand barriers, 1.5m ×1.5m and 1 m ×1m PLA sand barriers as the research objects, and analyzes the vertical spatial distribution characteristics of different sand particles in the windblown sand flow by means of field observation and indoor experiment. The results show that within the height of 0 - 30cm, the sand transport volume of the study area, 1.5m ×1.5m PLA sand barrier and 1m ×1m PLA sand barrier accounts for 96.6%, 87.78% and 86.96% of the total sand transport respectively;the sand transport rate within the PLA sand barriers of the two specifications decreases with a height as a power function, and the sand transport rate within the study area decreases with a logarithmic function;the sand transport rate for each height layer is the study area>1.5m×1.5m PLA sand barrier >1m ×1m PLA sand barrier;with the increase in height within 0 - 10cm of the two types of PLA sand barriers and the study area in the airflow, the content of fine-grained sand increased, while the content of very fine sand, medium sand and coarse sand showed a downward trend;within 10 cm – 90 cm, the amount of fine powder and very fine sand showed an upward trend, and the content of fine sand, medium sand and coarse sand showed a downward trend;when the wind sand entered the PLA sand barrier, the content of coarse sand and medium sand decreases, and the content of extremely fine sand and fine sand increases. The setting of the PLA sand barrier can significantly change the mechanical composition of the sand material in the wind sand flow, and effectively block the sand particles in the wind sand flow. The 1m ×1m specification has a more significant wind and sand fixation effect than the 1.5m ×1.5m specification PLA sand barrier.