山区河流河床结构表征新方法
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摘要
山区河流的河床结构是来水来沙与河床相互作用的产物,对河床阻力及输沙率的计算具有重要意义。为更科学地表征河床结构的细节特征,采用2017年2次考察金沙江小江流域干支流7个河段的地形测量数据,提出河床结构表征的4个新量纲一数(凹凸数、平均凹度、平均凸度和凹凸度)及其计算方法。新参数的计算原理简单而直观,能够从多角度表征河床结构发育程度及其形态特征,而且当河床结构发育程度较低时,凹凸度的表征结果更具有区分度。结果表明:新参数表征结果与前人单一参数的计算结果具有一致性;吊嘎河下游、陶家小河和清水沟的河床结构凹凸程度大,河床凸起"高凸",凹陷"深陡",河床阻力大,输沙率低;吊嘎河上游、小江、蒋家沟和蓝泥坪沟的河床结构凹凸程度小,河床凸起"低平",凹陷"浅缓",河床阻力小,输沙率大。
Riverbed structure in mountainous rivers is the product of the interplay between flow-sediment and riverbed,which determines the magnitude of riverbed resistance and significantly affects the bedload transport. In order to characterize the details of riverbed structure,this study proposed four new dimensionless parameters( concavity-convexity number,average concavity,average concavity,and concavity-convexity) of riverbed structure characterization and their calculation methods based on the topographic survey datasets of seven sections of the main stream and tributaries of Xiaojiang River( a tributary of Jinsha River in the upper Yangtze River) in April and September 2017. The calculation method of four new parameters is simple and intuitive. Four parameters represent the development degree of the riverbed structure and morphological characteristics of riverbed structure. Moreover,the characterization of the concavity and convexity is more distinguishable if the degree of the riverbed development is relatively lower. The results based on the application of the new method show that the bulge of the riverbed structure in the lower reaches of the Diaoga River,Taojia Creek,and Qingshui Creek is relatively high and convex,i. e.,the deep and steep depression,high resistance of river bed,and low sediment transport rate. However,the upper reaches of the Diaoga River,Xiaojiang River,and Jiangjia Creek,and Lanniping Creek,the bulge of the riverbed structure is relatively low and flat,i. e.,the shallow and gentle depression,low resistance of river bed,and high sediment transport rate.
Riverbed structure in mountainous rivers is the product of the interplay between flow-sediment and riverbed,which determines the magnitude of riverbed resistance and significantly affects the bedload transport. In order to characterize the details of riverbed structure,this study proposed four new dimensionless parameters( concavity-convexity number,average concavity,average concavity,and concavity-convexity) of riverbed structure characterization and their calculation methods based on the topographic survey datasets of seven sections of the main stream and tributaries of Xiaojiang River( a tributary of Jinsha River in the upper Yangtze River) in April and September 2017. The calculation method of four new parameters is simple and intuitive. Four parameters represent the development degree of the riverbed structure and morphological characteristics of riverbed structure. Moreover,the characterization of the concavity and convexity is more distinguishable if the degree of the riverbed development is relatively lower. The results based on the application of the new method show that the bulge of the riverbed structure in the lower reaches of the Diaoga River,Taojia Creek,and Qingshui Creek is relatively high and convex,i. e.,the deep and steep depression,high resistance of river bed,and low sediment transport rate. However,the upper reaches of the Diaoga River,Xiaojiang River,and Jiangjia Creek,and Lanniping Creek,the bulge of the riverbed structure is relatively low and flat,i. e.,the shallow and gentle depression,low resistance of river bed,and high sediment transport rate.
引文
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[7]李文哲,李志威,王兆印.推移质输沙对阶梯-深潭系统消能的影响[J].水科学进展,2017,28(3):338-345.(LI W Z,LI ZW,WANG Z Y.Effect of bed load transport on the energy dissipation of step-pool system[J].Advances in Water Science,2017,28(3):338-345.(in Chinese))
[8]李文哲,王兆印,李志威,等.阶梯-深潭系统的水力特性[J].水科学进展,2014,25(3):374-382.(LI W Z,WANG Z Y,LI Z W,et al.Study on hydraulic characteristics of step-pool system[J].Advances in Water Science,2014,25(3):374-382.(in Chinese))
[9]CHIN A.The morphologic structure of step-pools in mountain streams[J].Geomorphology,1999,27(3):191-204.
[10]ZIMMERMANN A,CHURCH M.Channel morphology,gradient profiles and bed stresses during flood in a step-pool channel[J].Geomorphology,2001,40(3/4):311-327.
[11]ABRAHAMS A D,LI G,ATKINSON J F.Step-pool stream:adjustment to maximum flow resistance[J].Water Resources Research,1995,31(10):2593-2602.
[12]NICKOLOTSKY A,PAVLOWSKY R T.Morphology of step-pools in a wilderness headwater stream:the importance of standardizing geomorphic measurements[J].Geomorphology,2007,83(3/4):294-306.
[13]WANG Z Y,XU J,LI C Z.Development of step-pool sequence and its effects in resistance and stream bed stability[J].International Journal of Sediment Research,2004,19(5):161-171.
[14]徐江,王兆印.阶梯-深潭的形成及作用机理[J].水利学报,2004,35(10):48-55.(XU J,WANG Z Y.Formation and mechanism of step-pool system[J].Journal of Hydraulic Engineering,2004,35(10):48-55.(in Chinese))
[15]余国安.河床结构对推移质运动及下切河流影响的试验研究[D].北京:清华大学,2008.(YU G A.Experimental study on streambed structures and bed load transport in an incised stream[D].Beijing:Tsinghua University,2008.(in Chinese))
[16]张康,王兆印,刘乐,等.山区河流河床结构对推移质输沙率的影响[J].天津大学学报,2012,45(3):202-208.(ZHANGK,WANG Z Y,LIU L,et al.Effects of riverbed structure on transport rate of bed load in mountain streams[J].Journal of Tianjin University,2012,45(3):202-208.(in Chinese))
[17]侯兰功.西南山区泥石流沟流域形态统计分析:以云南小江流域为例[J].水土保持研究,2006,13(3):94-96.(HOU L G.Statistical analysis of valley morphology on debris flow gully in mountain area of southwest:taking Xiaojiang Valley in Yunnan Province as example[J].Research of Soil and Water Conservation,2006,13(3):94-96.(in Chinese))
[18]张利国,傅旭东,郭大卫,等.山区卵砾石河流的阻力[J].水利学报,2013,44(6):680-686.(ZHANG L G,FU X D,GUOD W,et al.Flow resistance in gravel-boulder-bed streams[J].Journal of Hydraulic Engineering,2013,44(6):680-686.(in Chinese))
[19]张晨笛,王兆印,李志威,等.单个阶梯-深潭破坏的力学模型[J].水利学报,2014,45(12):1399-1409.(ZHANG C D,WANG Z Y,LI Z W,et al.A physically-based model of individual step-pool failure[J].Journal of Hydraulic Engineering,2014,45(12):1399-1409.(in Chinese))
[20]李志威,王兆印,张晨笛,等.人工阶梯-深潭破坏案例与稳定性分析[J].水科学进展,2015,26(6):820-828.(LI Z W,WANG Z Y,ZHANG C D,et al.Artificial step-pool destruction cases and stability analysis[J].Advances in Water Science,2015,26(6):820-828.(in Chinese))
[2]刘怀湘,王兆印,陆永军,等.山区下切河流地貌演变机理及其与河床结构的关系[J].水科学进展,2011,22(3):367-372.(LIU H X,WANG Z Y,LU Y J,et al.Mechanism of morphological evolution in incised river and its relationship to streambed structures[J].Advances in Water Science,2011,22(3):367-372.(in Chinese))
[3]刘怀湘,王兆印,余国安,等.典型山区小流域河床结构分布研究[J].水利学报,2012,43(5):512-519.(LIU H X,WANGZ Y,YU G A,et al.Study on distribution of streambed structures in a typical mountain river basin[J].Journal of Hydraulic Engineering,2012,43(5):512-519.(in Chinese))
[4]刘怀湘,王兆印,于思洋.山区河流河床结构的发育分布[J].清华大学学报(自然科学版),2010,50(6):857-860.(LIU HX,WANG Z Y,YU S Y.Growth distribution of the riverbed structures in mountain area[J].Journal of Tsinghua University(Science and Technology),2010,50(6):857-860.(in Chinese))
[5]WANG Z Y,MELCHING C S,DUAN X H,et al.Ecological and hydraulic studies of step-pool system[J].Journal of Hydraulic Engineering,ASCE,2008,130(7):792-800
[6]余国安,黄河清,王兆印,等.山区河流阶梯-深潭研究应用进展[J].地理科学进展,2011,30(1):42-48.(YU G A,HUANG H Q,WANG Z Y,et al.Research progress and application of step-pool systems in mountain streams[J].Progress in Geography,2011,30(1):42-48.(in Chinese))
[7]李文哲,李志威,王兆印.推移质输沙对阶梯-深潭系统消能的影响[J].水科学进展,2017,28(3):338-345.(LI W Z,LI ZW,WANG Z Y.Effect of bed load transport on the energy dissipation of step-pool system[J].Advances in Water Science,2017,28(3):338-345.(in Chinese))
[8]李文哲,王兆印,李志威,等.阶梯-深潭系统的水力特性[J].水科学进展,2014,25(3):374-382.(LI W Z,WANG Z Y,LI Z W,et al.Study on hydraulic characteristics of step-pool system[J].Advances in Water Science,2014,25(3):374-382.(in Chinese))
[9]CHIN A.The morphologic structure of step-pools in mountain streams[J].Geomorphology,1999,27(3):191-204.
[10]ZIMMERMANN A,CHURCH M.Channel morphology,gradient profiles and bed stresses during flood in a step-pool channel[J].Geomorphology,2001,40(3/4):311-327.
[11]ABRAHAMS A D,LI G,ATKINSON J F.Step-pool stream:adjustment to maximum flow resistance[J].Water Resources Research,1995,31(10):2593-2602.
[12]NICKOLOTSKY A,PAVLOWSKY R T.Morphology of step-pools in a wilderness headwater stream:the importance of standardizing geomorphic measurements[J].Geomorphology,2007,83(3/4):294-306.
[13]WANG Z Y,XU J,LI C Z.Development of step-pool sequence and its effects in resistance and stream bed stability[J].International Journal of Sediment Research,2004,19(5):161-171.
[14]徐江,王兆印.阶梯-深潭的形成及作用机理[J].水利学报,2004,35(10):48-55.(XU J,WANG Z Y.Formation and mechanism of step-pool system[J].Journal of Hydraulic Engineering,2004,35(10):48-55.(in Chinese))
[15]余国安.河床结构对推移质运动及下切河流影响的试验研究[D].北京:清华大学,2008.(YU G A.Experimental study on streambed structures and bed load transport in an incised stream[D].Beijing:Tsinghua University,2008.(in Chinese))
[16]张康,王兆印,刘乐,等.山区河流河床结构对推移质输沙率的影响[J].天津大学学报,2012,45(3):202-208.(ZHANGK,WANG Z Y,LIU L,et al.Effects of riverbed structure on transport rate of bed load in mountain streams[J].Journal of Tianjin University,2012,45(3):202-208.(in Chinese))
[17]侯兰功.西南山区泥石流沟流域形态统计分析:以云南小江流域为例[J].水土保持研究,2006,13(3):94-96.(HOU L G.Statistical analysis of valley morphology on debris flow gully in mountain area of southwest:taking Xiaojiang Valley in Yunnan Province as example[J].Research of Soil and Water Conservation,2006,13(3):94-96.(in Chinese))
[18]张利国,傅旭东,郭大卫,等.山区卵砾石河流的阻力[J].水利学报,2013,44(6):680-686.(ZHANG L G,FU X D,GUOD W,et al.Flow resistance in gravel-boulder-bed streams[J].Journal of Hydraulic Engineering,2013,44(6):680-686.(in Chinese))
[19]张晨笛,王兆印,李志威,等.单个阶梯-深潭破坏的力学模型[J].水利学报,2014,45(12):1399-1409.(ZHANG C D,WANG Z Y,LI Z W,et al.A physically-based model of individual step-pool failure[J].Journal of Hydraulic Engineering,2014,45(12):1399-1409.(in Chinese))
[20]李志威,王兆印,张晨笛,等.人工阶梯-深潭破坏案例与稳定性分析[J].水科学进展,2015,26(6):820-828.(LI Z W,WANG Z Y,ZHANG C D,et al.Artificial step-pool destruction cases and stability analysis[J].Advances in Water Science,2015,26(6):820-828.(in Chinese))