| 李明,胡春宏,方春明.三峡水库坝下游河道断面形态调整模式与机理研究[J].水利学报,2018,49(12):1439-1450 |
| 三峡水库坝下游河道断面形态调整模式与机理研究 |
| Study on pattern and mechanism of river section topography adjustment in the downstream of the Three Gorges project |
| 投稿时间：2018-03-10 |
| DOI：10.13243/j.cnki.slxb.20180205 |
| 中文关键词: 河床演变 造床作用 三峡工程 断面形态 水沙条件 |
| 英文关键词: river bed evolution bed-forming function the Three Gorges project section topography flow and sediment conditions |
| 基金项目:国家重点研发计划项目（2016YFC0402105） |
|
| 摘要点击次数: 17254 |
| 全文下载次数: 2934 |
| 中文摘要: |
| 2003年三峡水库蓄水运用后，长江中下游河道对新水沙条件的自适应调整十分复杂。本文重点关注河道横断面形态调整问题，分析表明，在减沙效应影响的河段内，河道总体冲刷过程中断面形态的变化可以分为3种模式：整体下切型、平移调整型和复合调整型。针对长江中下游大部分为受控型河道的现状，提出采用形心相对深度指标对断面形态变化进行定量分析。结果表明，在河道冲刷过程中，断面形态既存在冲滩为主的坦化现象，也存在冲槽为主的锐化现象。结合水沙条件变化分析，阐述了3种断面形态调整模式的水沙作用机理，指出在新水沙条件下河道转变为冲刷型后，断面形态的调整方向由主流区的强冲刷效应所主导，且因中水流量级的造床作用凸显，洪水流量级的造床作用被明显削弱。在原始深槽走向与优势流量级主流倾向位置差别较大的河段，河道横断面优先表现出平移调整模式；在深槽走向相对平顺的河段，河道横断面的调整以复合调整模式为主，呈现出冲深淤浅的锐化特征。 |
| 英文摘要: |
| After the use of the Three Gorges Reservoir in 2003, the adaptive adjustment of the middle and lower reaches of the Yangtze River is very complicated because of the variation of incoming flow and sediment. The analysis shows that in the influence of sand reduction, the change of the section form can be divided into three modes:the whole undercutting,the translational adjustment and the compound adjust-ment. For the middle and lower reaches of the Yangtze River are mostly controlled channels, the relative depth of cross section centroid is presented as a useful index of section topography to reveal the mecha-nism of river cross section adjustment. Through quantitative analysis, it is found that during the bed mak-ing process the sectional topography has not only the sharpening phenomenon due to deep groove scouring, but also the attenuation phenomenon due to beach scouring. Both directions are closely related to the strong scouring effect of the main flow region caused by the new flow and sediment conditions, and also up to bed-forming function of normal water has been strengthened and bed-forming function of flood water has been significantly weakened. So, in the channel where the direction of the thalweg is far different from the mainflow position of the dominant flow level, the cross sections show translational adjustment mode firstly, and in the straight channel, the cross sections mainly show compound adjustment mode, accompanied by making the sectional topography more sharp. |
|
查看全文
查看/发表评论 下载PDF阅读器 |
| 关闭 |
|
|
|