长江口细颗粒泥沙基本特性研究

Studies on basic characteristics of fine sediment in Changjiang Estuary

本文较系统地阐述了长江口细颗粒泥沙的粒度、矿物、电荷与絮凝的基本特性，综合分析结果，提出了以３２微米作为粗颗粒泥沙与细颗粒泥沙划分的界限，以利推动我国细颗粒泥沙研究的深入．

The Changjiang Estuary is a transitional setting from land towards the sea. In which two kinds of dynamics, fluvial and tidal currents; two kinds of media, fresh and salt water, and two kinds of sediment resources, from sea and from land basin, form a complex changeable modern estuarine environment and the suspended sediment, fluid mud and bed sediment structure the modern estuarine sedimentation system.Based on the facts that about 90. 52% of suspended sediment are finer than mid-silt (0. 032￣0. 016mm), 92. 6% of surfacial electronic charges are concentrated on the grains of finer than 0. 032mm and 0. 032mm is also the critical diameter of flocculation, it is suggested that 0. 032mm may be used as the critical diameter of coarse and fine sediment, which will be benificial not only to the comparison and application of different data but also to the further studies on the fine sediment. The systematical studies on the basic characters of fine sediment in the Changjiang Estuary are not only helpful to understand the transportation, deposition and resuspension processes of the suspended sediment, but also benificial to further understand the forming mechanism of the great mouth bar. Parts of the results have been used in the waterway choice of the north channel and it is believed that the results will have more practical values in the comprehensive plan and in the management of deep waterway in the Changjiang Estuary.