新疆戈壁地区风沙流结构及其粒径特征研究

Study on Wind-blown Sand Flow Structure and Particle Size Characteristics in Gobi Area of Xinjiang

为掌握研究区域风沙流活动情况,设计并完成了长跨时(2016年5月—2018年5月)的戈壁风沙流现场累积观测。基于观测数据和砂土样品,对研究区域的风沙流活动特征及其结构进行系统分析,在此基础上建立输沙通量廓线函数模型。结果表明:1)观测期间现场输沙率水平在177—330 g/(cm·a),均值约247 g/(cm·a)。2)风沙流和地表砂土粒径分布分别呈双峰和单峰型,且风沙流中砂土占比与地表砂土占比的比值随粒径增大而减小。3)建立的线性-多项式-幂函数和指数-幂函数两种模型都能较准确地描述风沙流的输沙通量廓线,拟合优度均值超过0.98,适用于反映现场风沙流结构。

In order to study the wind-blown sand flow activities in the research area,a long-span(2016.05-2018.05)wind-sand flow observation was designed and completed.Based on the observation data and sand sample,the characteristics and structure of the activities were analyzed,and then the profile function model of sediment transport flux was established.The results showed that,1)During the observation period,the on-site sediment transport rate level was 177-330 g/(cm·a),with the average value of about 247 g/(cm·a).2)The particle size distribution of aeolian sand flow and surface sand presented bimodal and unimodal types,respectively,and the ratio of the proportion of the sand in the wind-blown to that on the ground decreased with the particle size increased.3)The established linear-polynomial-power function and exponential-power function can accurately describe the sediment transport flux profiles of wind sand flow,and the average correlation coefficient between the observations and the fitted results exceeded 0.98,which was suitable for reflecting the wind sand flow structure on site.