汉江秋汛期两江交汇处超常淤积成因及影响分析

Analysis of cause and influence of supernormal sedimentation in confluence of the Yangtze River during autumn flood

针对2011年度汉江秋汛所导致的汉口边滩超常规淤积现象,采用演变分析结合数学模型的手段对其水沙运动规律及产生的原因进行分析,并对其影响及发展变化趋势进行预测。结果表明:汉江入汇使得汉口水道武汉关附近形成一定的缓流区域,遇汉江秋汛加之长江来流量较小,武汉关附近缓流区域范围大幅度增加,使得汉口边滩大幅度淤长。汉口边滩处于主流带与主输沙带自左向右的过渡区域,河道水流特性决定了汉口边滩难以长期稳定,在汉口边滩发生较大幅度的淤积后,一般在秋汛后次年长江汛期会迅速冲刷,因而不会对河道形势及长期演变规律产生影响。

A supernormal sedimentation occurred at the confluence of the Yangtze River during the autumnflood of Hanjiang River in 2011. In this paper, evolution analysis and numerical simulation on the causes and trendof this supernormal sedimentation were presented. The result shows that, a tranquil flow area exists near Wuhan dueto the inflow of Hanjiang River. When the autumn flood of Hanjiang River meets with lesser discharge in the mainflow at the same time, the tranquil flow area will rapidly extend and cause supernormal sedimentation at Hankouside bar in confluence area. However, the sedimentation body will be sufficiently eroded for it is located at the left toright transition region of the main flow, therefore, the Hankou side bar will rapidly reduce after the supernormal sed-imentation, and will not exert influences on river regime and further evolution.