【摘要】 选取东柳沟流域作为研究区域,通过分析主河道中泥沙颗粒的粒径特征,研究流域沉积物的分布规律及其粒径变化过程。应用激光粒度仪对研究区内的河道沉积土样进行测定,使用秩和检验对泥沙颗粒特征进行分析,得到流域沉积泥沙粒径分布及变化规律。结果表明,根据中值粒径和河道比降的变化,将东柳沟流域分为丘陵区、沙丘区和农田区3个区域。流域沉积泥沙的中值粒径从上游丘陵区到下游农田区逐渐呈减少的趋势。3个分区的沉积泥沙级配特征有显著不同,丘陵区的沉积泥沙主要由粗沙构成,极粗沙和中粗沙约占57%。而沙丘区和农田区以细沙为主,且越往下游细沙含量越大,其中沙丘区沉积物中细沙及更细的颗粒所占比例约为64%,农田区沉积物中细沙及更细的颗粒所占比例约为84%。据此表明,东柳沟的侵蚀过程在空间上表现为水力侵蚀和风力侵蚀作用的交替叠加,其中沉积泥沙中值粒径变化最剧烈的地方是风蚀和水蚀交错最为频繁的区域。更多还原

【Abstract】 Sediment deposited in the river channel and river bank in Dongliugou watershed were collected as samples and analyzed in our research.The sediment characteristic and its size distribution in Dongliugou watershed were analyzed.Laser particle analyzer was applied to measure the sediment characteristic of processed samples,and Wilcoxon rank sum test was employed to detect whether change point exist in different sediment characteristic.The results showed that,Dongliugou watershed was divided into three regions from the upper Dongliugou watershed to the downstream,i.e.hilly region,desert region,and agrarian region.The median size of sediments decreased step by step from hilly region located in the upper Dongliugou watershed to agrarian region in the downstream.The characteristics of sediments in the three regions were quite different from each other.The proportion of coarse sand was about 57% in the hilly region,while the proportion of fine sand in the desert region and agrarian region were 64%and 84%respectively.The results indicated that both wind erosion and water erosion took place in the Dongliugou watershed,and the variation of the sediment characteristics was very large in the region where serious complex erosion by wind and water proceeded.更多还原