长江口细颗粒泥沙絮凝沉降影响因素分析

The analysis for influencing factors of fine sediment flocculation in the Changjiang Estuary

根据静水和动水条件下的细颗粒泥沙沉降试验结果 ,应用灰色模型分析中的关联度分析理论 ,分析了影响细颗粒泥沙絮凝沉降的主要因素 .根据关联度的大小指出 ,影响细颗粒泥沙絮凝沉降的主要因素依次为水温、沉降历时、盐度、粒度、含沙量和流速 ,其中盐度和粒度是阈值型影响因素 ,沉降历时、含沙量和流速是连续型影响因素 ,水温是具有阈值型和连续型双重特性的影响因素 .只要阈值型影响因素达到或超过了阈值 ,细颗粒泥沙就发生絮凝作用 ,因素值的变化对沉降强度影响不大 .连续型影响因素对细颗粒泥沙絮凝沉降的影响是连续的 ,它们不仅影响絮凝作用发生 。

Based on the test data under dynamic water and static water, main factors which influence the fine sediment flocculation are analyzed using the relative analysis theory of the gray model analysis. It is pointed out that the main influencing factors are water temperature, settling time, salinity, grain size, sediment concentration and current velocity according to relevant values. In those factors, the salinity and the sediment grain size are critical type influencing factors, but the settling time, the sediment concentration and the velocity are continuous influencing factors, and the water temperature has characteristics of both the critical type and continuous type. When the critical values of the critical type influencing factors are reached or exceeded, the fine sediments are flocculated but the values do not influence the settling strength of the floc. The influence of the continuous type influencing factors is continuous. They not only influence the flocculation but also the settling strength of the floc.