南疆铁路风沙流结构特征研究

Characteristics of gobi sand-drift along south Xinjiang railway

通过对南疆铁路戈壁风沙流进行现场观测研究,提出了关于风沙流密度的计算方法,将大风所携沙粒定量化,解决了风沙运动研究中如何利用现场定时观测研究风沙流动态变化的技术难题。根据现场实测资料分析,揭示了南疆铁路风沙流密度随高度和风速的变化关系。从中可以看出,风沙流密度随高度变化显现斜"L"形,以3m高为分界点;而相对的风沙流密度与风速则显现正相关变化,当高度为2m、风速≤40m/s时,风沙流密度随着风速的增大,其变化趋势逐渐变缓,其最大值逐渐趋近于0.0339g/m3。沙粒颗分试验结果表明"戈壁风沙运动存在较明显的分层现象,所携沙粒粒径以0.1～0.25mm为主。

By wind-blown sand movement observation and analysis along south Xinjiang railway,a new concept of the density of wind-blown sand has been indicated in this paper.The difficult problem of research in sand drift movement has been solved by the density of wind-blown sand.The study showed the relation between height and the density of sand blown,and the relation between the density of wind-blown sand and wind velocity.The experiment results are：（1） The density of wind-blown sand decreases with the raise of height in the fixed wind velocity,which has a good agreement with the form of an inclined ＂L＂.（2） The density of wind-blown sand increases with wind velocity in the same height.The max numerical value is close to 0.0339g/m^3,when the wind velocity is less than 40m/s in the height of 2 maters.（3） The result of sand particle size analysis showed that the most of the segment is 0.1-0.25mm and the sand drift movement has a delamination phenomenon.