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长江中下游长河段长时段的演变资料分析表明河势调整往往会向下游传递,但是部分河段却能阻隔这种河势调整的传递效应,称之为阻隔性河段。统计表明,阻隔性河段应同时具有单一微弯的平面形态、凹岸抗冲性较强且中上段无挑流节点、河宽随水位变化率不超过45等三个特征。进一步分析表明,这种河段具有阻隔性的根本原因是其能够归顺不同流量级的主流平面位置,使得无论上游河势如何调整,其出流的主流平面位置基本稳定,为下游河段提供相对稳定的入流条件。河道整治过程中,宜抓住有利时机塑造阻隔性河段效果,无阻隔性影响的长河段宜自上而下系统规划整治,对大幅度崩岸、滩体大幅萎缩等可能破坏阻隔性的变化应及时整治,防止阻隔性丧失。
The long-term evolution of the Changjiang River reaches the middle and lower reaches of the Yangtze River. Analysis of the data shows that river regulation tends to be transmitted downstream, but some of the river channels can block the transfer effect of such river regulation, which is called the barrier river. The statistics show that the barrier section should have the shape of a single microbend at the same time. The concave bank should have a strong anti-scour property and no upstream node and the width of the river should not change more than 45% with the water level. Further analysis shows that the root cause of such a barrier is that it can go to the mainstream of different flow levels, so that no matter the upstream river potential is adjusted, the outflow of the mainstream plane is basically stable and provides the relative Stable inflow conditions. During the course of river course improvement, it is advisable to seize the favorable opportunity to shape the effect of barrier river. The long reach without barrier effect should be planned and rehabilitated from top to bottom. In the case of large bank collapse and drastic shrinkage of beach body, the barrier change may be damaged Remediation should be promptly to prevent the loss of barrier.