长江河口底沙运动规律

THE BEDLOAD MOVEMENT IN THE CHANGJIANG RIVER ESTUARY

于1981－1988年以浅地层剖面仪和回声测深仪取得沙波观测资料，运用这些资料以及河床表层沉积物和历年河口水文、地形资料，采用水文学、沉积学与泥沙运动力学相结合的研究方法，分析长江河口底沙的运移规律。结果表明：长江河口底沙运动非常频繁，一般有单颗粒滚动、跳跃，沙波及沙体推移等形式；在沙质床面上沙波发育良好，其形成、发展和消失与潮差和落潮流速有一定的相关性，因受涨、落潮流改造，沙波难于得到充分发展；沙体推移为长江河口底沙运动的主要形式，推移量很大，有时甚至能使滩槽移位，迫使通海航道改线。研究底沙运动规律为长江河口治理提供科学依据。

Sandwaves in the Changjiang River Estuary were measured in 1981-1988 with a shallow sediment profiler and an echosounder. Study based on the data and the grain size and bedform of surface sediment, and data over .the years on hydrology and topography indicate that the bedload movement by rolling and saltation is of great significance to sediment transport and is the principal factor responsible for sandwave and sandbody development in the estuary. The sandwaves were found well-developed, which is related to the tidal range and the velocity of ebb current.However, their further growth is restricted by strong flood current prevailing in the estuary. The significant bedload and the obvious and frequent shifting of the sand bodies sometimes cause the positions of the mavigational channels to change. As a result, ships are regularly forced to change their navigation course.