本文關(guān)鍵詞： 彎曲河流 崩岸 橫向淘刷 泥炭 若爾蓋盆地　出處：《工程科學(xué)與技術(shù)》2017年S1期 　論文類型：期刊論文

【摘要】：彎曲河流凹岸在近岸水流淘刷作用下發(fā)生崩岸是河灣橫向遷移的直接動(dòng)力。2011—2016年野外調(diào)查表明,黃河源的若爾蓋盆地發(fā)育眾多的彎曲河流,其河岸上部為泥炭層,下部為粉沙層,可稱為泥炭型彎曲河流。通過分析泥炭型彎曲河流的河岸粉沙層淘刷過程,以及崩岸臨界力矩平衡條件,從機(jī)理上研究泥炭型彎曲河流的橫向淘刷速率與崩岸機(jī)制。泥炭型彎道的崩岸分為粉沙層淘刷與泥炭層崩塌這兩個(gè)過程,并將河岸粉沙層的淘刷簡(jiǎn)化為3個(gè)階段:1)凹岸的彎頂下游處最先受到水流的淘刷;2)開始階段以橫向淘刷直至最大距離;3)逐漸轉(zhuǎn)變以縱向淘刷為主。進(jìn)而,建立近岸流速與淘刷距離的關(guān)系式,近岸流速隨淘刷距離增加而減少,推導(dǎo)出粉沙層橫向淘刷速率的表達(dá)式,提出確定淘刷系數(shù)的方法,推導(dǎo)出泥炭層拉張臨界破壞的力矩平衡方程,獲得了泥炭塊的臨界崩塌寬度表達(dá)式,其計(jì)算值與實(shí)測(cè)值較接近。
[Abstract]:The collapse of the concave bank of a curved river is a direct driving force for the lateral migration of the river bay. The field investigation in 2011-2016 shows that there are many curved rivers developed in the Zoige basin from the source of the Yellow River. The upper part of the river bank is peat layer and the lower part is silt layer, which can be called peat bend river. The lateral scouring rate and bank collapse mechanism of peat bend river are studied from the mechanism. The bank collapse of peat bend can be divided into two processes: silt scouring brush and peat bed collapse. The scouring of silt bed of riverbank is simplified as three stages: 1) the bottom of the bend top of the concave bank is first scoured by the current. 2) at the beginning stage, the transverse scouring was carried out until the maximum distance; 3) gradually changing to longitudinal scouring. Then, the relationship between the velocity and the distance of scouring is established. The velocity decreases with the increase of scouring distance, and the expression of the lateral scouring rate of silt is deduced. The method of determining scouring coefficient is put forward, the moment equilibrium equation of peat layer tensile critical failure is derived, the expression of critical collapse width of peat block is obtained, and the calculated value is close to the measured value.
【作者單位】： 長(zhǎng)沙理工大學(xué)水利工程學(xué)院;水沙科學(xué)與水災(zāi)害防治湖南省重點(diǎn)實(shí)驗(yàn)室;黃河水利科學(xué)研究院;
【基金】：水利部黃河泥沙重點(diǎn)實(shí)驗(yàn)室開放課題基金資助項(xiàng)目(2017005) 國(guó)家自然科學(xué)基金資助項(xiàng)目(91547112;91647118) 國(guó)家國(guó)際科技合作專項(xiàng)資助(2014DFG72010) 湖南省研究生科研創(chuàng)新項(xiàng)目資助(CX2016B390)
【分類號(hào)】：TV147
【正文快照】： 彎曲河流以優(yōu)美的形態(tài)和廣泛的適應(yīng)性激起人們探究其發(fā)育條件、崩岸過程與演變機(jī)制。彎曲河流廣泛發(fā)育于沖積平原、草原、熱帶雨林、極地凍土、沙漠邊緣,在冰原、深海也有非沖積彎道的行蹤或遺跡[1-5],野外考察表明在青藏高原也廣泛發(fā)育不同尺度的彎曲河流,特別是黃河源的若爾

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1 祖文辰,張則有,白燕;關(guān)于中國(guó)東北地區(qū)泥炭礦評(píng)等分級(jí)的探討[J];東北師大學(xué)報(bào)(自然科學(xué)版);1997年02期

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