长江口深水航道三期工程北槽演变特征及航道回淤部分原因分析

Evolution characteristics of north passage and back-silting in navigation cannel during the third phase improvement project of deep-water channel

对长江口深水航道三期2004—2007年工程期间的北槽河势演变进行了分析总结。分析表明北槽总体上呈现了拦门沙区域的"洪淤枯冲"规律,而且北槽上段北滩地一直淤积,W3附近南滩地一直发生淤涨,导致滩地坡度较大,且航道南侧滩槽水深比和航道回淤量非线性负相关性非常强。W3附近南滩一直淤积、滩槽水深比小、滩地坡度大、8 m线宽度最小等因素是使近底高含沙水体易进入航道导致北槽中段回淤量大的部分原因。

The evolution of the river regime in the north passage after the construction of the second phase of the Yangtze River deepwater navigation channel project from 2004 to 2007 is analyzed. The results show that the principle of“deposit in flood season while erosion in dry season”applies generally to the mouth bar zone of the north passage. Besides, the north beach of the upstream of the north passage deposits all the time. Deposition also happens on the south beach near W3, which leads to a high slope of the shoal. In addition, the nonlinear negative correlation effect between the depth ratio of the south shoal channel and the channel siltation volume is significantly strong. Several reasons can be concluded to explain the high siltation volume in the navigation channel, such as the continuous deposition at the W3 south beach, small depth ratio of the shoal channel, high slope of the beach and the fact that the width of the 8m-depth line is the smallest.