摘要
基于2008年1月(枯季)和2012年8月(洪季)长江中下游实测水沙资料,发现洪枯季悬沙絮凝特性存在显著差异,枯季絮凝程度比洪季显著偏高,与长江河口情况相反。进而从水动力和泥沙特性两个方面对比分析了中下游淡水絮凝的主要影响因素,结果表明在流速较小时,小于1m/s,流速增大能够促进絮凝;而当流速较大时,流速继续增大不利于絮团的发育。此外,随着含沙量的增大,絮团有效密度增大,指示絮凝程度降低。悬浮泥沙分散颗粒越细,絮凝程度越高,并且大絮团主要由黏土组分构成。
Based on the field observation in January 2008 （dry season） and August 2012 （flood season） in the middle stream of the Yangtze River.Flocculation characteristics were found significantly different between dry and flood season.The size of in-situ floc was larger in dry season,which was opposite with the situation in the Yangtze estuary.Further analysis was focused on the hydrodynamic and sediment characteristics,the results show that flocculation was promoted by the accretion of velocity when the flow velocity was smaller than 1.0m/s.However,larger velocity would weaken the development of flocs once the velocity surpassed 1.0m/s.In addition,floc effective density increased with the increase of sediment concentration.The finer the dispersed particles,the higher the degree of flocculation,and large floc were mainly constituted by clay.
出处
《泥沙研究》
CSCD
北大核心
2014年第5期59-64,共6页
Journal of Sediment Research
基金
国家自然科学基金项目(41276080
51320105005)
基金委创新研究群体项目(41021064)
上海市科委重点项目(12231203101
12230707500)
关键词
长江
淡水絮凝
洪枯季对比
Yangtze River
freshwater flocculation
flood and dry season comparison
