鸭绿江西水道口悬沙动力特征

DYNAMIC CHARACTERISTICS OF SUSPENDED SEDIMENTS IN THE WEST CHANNEL OF THE YALU RIVER

根据鸭绿江西水道口外两个站位大小潮实测悬沙数据,结合表层沉积物特征及潮流动力分析结果,从悬沙浓度、悬沙输沙量和悬沙粒级3个方面,分析了悬浮泥沙浓度大小潮时空变化特征及其与潮汐、潮流动力因素的关系,净输沙量特征及输沙方向、悬沙各粒级百分含量与涨落潮及泥沙沉积物之间的关系等内容。计算分析表明:影响悬沙动力特征的主要因素为空间位置、动力强弱及泥沙源;1#站位细粒沉积物丰富,潮流及输沙受口门地形控制,2#站位地形平坦,沉积物颗粒粗,泥沙源来自异地;悬沙浓度受潮流、潮汐动力影响呈规律性变化,输沙量受潮流动力、泥沙来源双重影响;两个站位悬沙粒级百分含量随涨落潮的峰值变化及与流速、流向、潮位的对应关系的不同,有效的指示了沉积物空间分布特征,反映了外部环境对悬沙的作用过程。

Two stations of suspended sediments during neap and spring tides were measured in the west channel of the Yalu River. Together with analysis results of surface sediment characters and current forces, this article does some researches about suspended sediment concentration variations and their relations with tides and current forces during spring and neap tides, does calculation of sediment discharge of unit width and net sediment discharges and direction analysis, and gives relations between suspended sedi- ment grain sizes and tides and bed sediments, which mainly involves sediment concentration, discharge and grain size. The results show that the main factors influencing suspended sediment characters are space position, current strength and sediment source. Station 1 # is rich in fine sediment, and current and sediment transport are controlled by terrain features. Station 2 # has flat terrain and coarse sediment, and sediment source comes from other positions. Suspended sediment concentration varies regularly because of influence of current and tide force,and sediment discharge is dominated not only by current force, but also by sediment source. Suspended sediment grade percentage at two observation poins has different peak values with ebbs and flows resulting from different current velocities, directions and tidal levels. This indicates sediment space distributions and reflects external environment＇s effects on suspended sediment.