【摘要】 1991～2010年间长江口北支河段实施了诸多河道整治工程,天然动力沉积环境受到了人类活动的影响。为探讨在新的水沙条件下北支河段沉积物的特征,对丰水年2012年和枯水年2013年两个典型年枯季的大范围沉积物取样样品资料进行了分析。结果表明:①北支河段沉积物中值粒径平均为0.055 mm,颗粒较粗;沉积物类型以黏土质粉砂和砂为主,砂集中分布在灵甸港以上河段,黏土质粉砂主要分布在新村沙至连兴港河段。②纵向上,从崇头至连兴港沉积物中值粒径总体呈减小趋势,且沉积物沿程特征差异显著,以灵甸港为界,上段沉积物中值粒径约是下段的2.5倍;横向上,沉积物粒径主要表现为"槽粗滩细"。③丰水年粒径粗于枯水年,尤其在以流域来沙为主的灵甸港以上河段。更多还原

【Abstract】 A large number of river harnessing projects were carried out in the North Branch of the Yangtze River from 1991 to 2010 and the nature dynamic sedimentation environment was impacted by the human activities. In order to study the characteristics of sediments in the North Branch under the new flow and sediment conditions, this paper analyzes the sediment samples taken in a large scope during typical wet year of 2012 and typical dry year of 2013. The results show:(1) The mean median diameter of the sediments in the North Branch is 0.055 mm, belonging to coarse particles. The dominant sediments are clayey silt and sand, and the sand is mainly distributed in the upstream reach of Lingdian port, while the clayey silt is mainly distributed in the reach from Xincunsha to Lianxinggang.(2) In the longitudinal direction, from Chongtou to Lianxing port, the overall decrease trend of mean median diameter of the sediments was observed, and the difference in sediment characteristics was significant. Taking Lingdian port as the boundary, the median diameter of the upper section was about 2.5 times that of the lower section. In the transverse aspect, the grain characteristics are mainly coarser in the channel and finer on beach.(3) In wet years, the sediment particle size is larger than that in dry years, especially in the upper reach of Lingdian port where the sediment comes from the upstream river rather than from the sea.更多还原