灌丛密度对沙粒粒度和起动风速影响研究

Effect of shrub density on grain sizes and threshold wind velocity

选择了位于宁夏中卫市西北角的中国科学院野外风沙观测场风沙工程实验区,采集不同密度灌丛区沙样,通过室内分析及风洞实验,研究了灌丛迎风和背风方向沙粒粒度结构及起动风速特征,得到以下结论:灌丛周围粒度分布曲线属高狭峰偏态分布型,灌丛的存在有利于风蚀中细沙和极细沙的截留;同时灌丛密度大小对于沙粒粒度特征及其起动风速都有重要影响,经文中详细分析,灌丛的最佳防护密度为12%～15%。

Based on the collected sand samples around the shrubs with different densities at the Sand Drift Observation Station of Chinese Academy of Sciences,the grain size parameters and the threshold wind velocity are studied through laboratory analysis and wind-tunnel experiments.The results reveal that the modal shape of the particle size-frequency distribution belonged to high-narrow peak,and the existence of shrubs was advantageous to hold fine sand and medium fine sand.The density of shrubs had important influence on the grain size parameters and threshold wind velocity and the most effective densities were 12%～15% for abating wind erosion.