本文關(guān)鍵詞： 阻隔性河段 水流動力軸線 河道邊界 長江中下游　出處：《地理學(xué)報》2017年05期 　論文類型：期刊論文

【摘要】：阻隔性河段能夠阻隔上游河勢調(diào)整向下游的傳遞,對穩(wěn)定河勢起到關(guān)鍵性作用。本文以長江中下游34個單一河段為研究對象,在系統(tǒng)總結(jié)長江中下游河道演變規(guī)律的基礎(chǔ)上,歸納出阻隔性河段控制要素包括:單一微彎的河道平面形態(tài)、河段中上部無挑流節(jié)點;河相系數(shù)小于4;河道縱比降大于1.2?;凹岸黏粒含量高于9.5%;床沙中值粒徑大于0.158 mm等。從Navier-Stokes方程出發(fā),推導(dǎo)出河灣水流動力軸線彎曲半徑的表達式,進而分析了各控制要素對水流動力軸線擺動及阻隔性河段形成的作用。阻隔性河段的判別條件為:不同流量級下水流動力軸線擺動力與河道邊界條件約束力的比值始終小于1;阻隔性河段作用機理在于:即便上游河勢發(fā)生調(diào)整,本河段的河道邊界始終能約束主流擺動幅度,歸順上游不同河勢條件下的主流平面位置,為下游河道提供了相對穩(wěn)定的入流條件,從而阻隔上游河勢調(diào)整向下游傳遞。
[Abstract]:The barrier River can adjust the upstream to the downstream river barrier transfer, to the key role of the stable regime. In this paper, the Yangtze River 34 single river as the research object, based on systematic analysis of middle and lower Yangtze River channel evolution, summed up the barrier of control elements include: single curved micro channel morphology in the upper reach, mudo flow node; river facies coefficient is less than 4; the longitudinal gradient is greater than 1.2?; clay particle content higher than 9.5% concave; sediment median particle diameter greater than 0.158 mm. Based on the Navier-Stokes equation, the deduced bend flow dynamic axis bending radius, and then analyzes the various factors on the flow control dynamic axis swing and barrier reach. Sufficient conditions for the river barrier: different discharge ratio of the flow dynamic axis shaking force and boundary conditions of channel binding was always less than 1; Is the river barrier mechanism: even if the upstream river changed, the river channel boundary always constrains the mainstream swing, the main plane position to different upstream water potential conditions, provided a stable flow condition for the downstream channel, thereby blocking the upstream to the downstream river regime.

【作者單位】： 武漢大學(xué)水資源與水電工程科學(xué)國家重點實驗室;湖北省水利水電規(guī)劃勘測設(shè)計院;長江勘測規(guī)劃設(shè)計研究有限責(zé)任公司;工程泥沙交通運輸行業(yè)重點實驗室交通運輸部天津水運工程科學(xué)研究所;
【基金】：國家自然科學(xué)基金重點項目(51379155) 國家科技支撐計劃項目(2013BAB12B02-02) 國家重點研發(fā)計劃(2016YFC0402306,2016YFC0402106) 中央級公益性科研院所基本科研業(yè)務(wù)(TKS160103)~~
【分類號】：TV147
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本文編號：1501093