荆江河段冲刷下切关键河段及节点分析

Analysis on the key reaches and segments of scour in the Jingjiang River

随着长江上游梯级水库的建设运行,新水沙条件下荆江在较长一段时期内持续冲刷。采用水沙数学模型预测荆江冲淤演变,结果表明其沿程冲淤变化波动明显。基于启发式分割算法(BG算法),对荆江的冲淤预测结果进行非平稳冲淤序列分割分析,确定了荆江冲刷程度相对严重的8个关键河段和13个冲刷突增的关键节点,与实测水面比降分析结果类比,其中7个关键河段以及8处关键节点得以相互映证。研究成果显示,基于BG算法检测河道冲刷关键节点是一种可行方法。

With the cascade reservoirs in the upper reach of the Yangtze River have been implemented,Jiangjiang Reach which under a different inflow sediment condition has been continually scoured during a long period.Aone-dimensional flow-sediment model was employed to simulate the scour and deposition of the Jingjiang River in the next two decades,which indicated obviously that the scour and depositionwere not stable along the river.The Bernaola-Galvan method was used to segment the nonlinear scour and deposition series into several subsets with different scales.Eight key segments and thirteen key sections of Jiangjiang River were obtained finally.Compared with the research which gave the key segments and sections of Jingjiang river by analysis of the water surface slop of observation data,there were 7 key segments and 8 key reaches can match with each other.Results indicated that the Bernaola-Galvan method was reliable to obtain the key segments and the key sections of scouring river.