作　　者： ; ; ; ; ; ;

机构地区： 华东师范大学河口海岸科学研究院河口海岸学国家重点实验室

出　　处： 《泥沙研究》 2008年第3期26-32,共7页

摘　　要： 分别于2006年枯（2月）和洪（8月）季利用较先进又较实用的现场观测仪器，对长江河口絮凝泥沙颗粒粒径、浮泥体及变化过程，以及与此相关的动力因子进行了现场现测，获得一批最新原始观测数据。观测数据显示：长江河口悬沙主要来源于长江流域的细颗粒冲泻质，小于32μm的细颗粒泥沙占80％以上，悬沙单颗粒粒径均值为3．6—6．8μm。在洪季流域来沙集中期，悬沙颗粒较细，均值为3．6-5．5μm，而枯季流域来沙少，悬沙颗粒略粗，均值为5．9～6．8μm；长江河口细颗粒泥沙絮凝环境良好，实测平均絮凝颗粒粒径为61．5μm，是分散单颗粒粒径的10倍多，最小絮凝颗粒粒径为27．4μm，最大为107μm，最大絮凝颗粒出现在0．4-0．7m／s的中等流速时段。在盐水到达的上界线徐六泾区域实测絮凝颗粒粒径相对较小，均值为32．6-60．4μm，而南北槽最大浑浊带区域絮凝颗粒粒径最大，均值为57．3—79．2μm，实测洪季絮凝颗粒粒径比枯季大，洪季均值为60．4—79．2μm，枯季均值为42．5～66．6μm。此外，长江河口浮泥发育与细颗粒泥沙絮凝快速沉降有关，而最大浮泥层常常发生在最大絮凝颗粒粒径出现的后期时段，故长江河口细颗粒絮凝沉降是浮泥形成的主要物质来源。 The in-situ observations of floccule size, fluid mud and the related dynamic factors in the Changjiang Estuary were made in February and August of 2006, respectively. The original data were obtained firstly by using the advanced and practical equipments. The results are shown that the sediment in the Changjiang Estuary comes from the wash load of the Yangtze River. The grain size of fine sediment, with a range of less than 32μm, accounts for more than 80% of sediment in the Changjiang Estuary, and associated median size is about 3.6 -6.8μm. The grain-size of the suspended sediment is about 3.6 - 5.5μm in the flood season and 5.9 - 6.8μm in the dry season, respectively. Due to the better situation in the Changjiang Estuary provided for the fine sediment flocculation, the floccule size is about 61.5μm. This is ten times bigger than the size of monodispersed sediment. The smallest floccule size is about 27.4μm and the-biggest is about 107μm occurred when the current velocity is within the range of 0.4 - 0.7 m/s. The median floccule size is about 32.6 - 60.4μm in the upstream limit of the salt water intrusion, the Xuliujing area, and is about 57.3-79.2μm occurred in the Turbidity Maximum. The value of the median floccule size in the Xuliujing area is smaller than that in the Turbidity Maximum. The median floccule size is about 60.4-79.2μm in the flood season and 42.5- 66.6μm in the dry season, respectively. Obviously, the value of the median floccule size in the flood season is bigger than that in the dry season. Furthermore, the development of fluid mud is related to the flocculation and deposition of the fine sediment in the Changjiang Estuary. The thickest fluid mud layer often occurrs in the later period of the formation of the biggest floc. Therefore, the flocculation and deposition of the fine sediment are the main sources of fluid mud.

关 键 词： 泥沙运动 长江河口 絮凝粒径 浮泥 盐度 潮流速

领　　域： [水利工程]