水科学进展
水科學進展
수과학진전
2015年
2期
178-186
,共9页
田培%潘成忠%许新宜%杨帆%李长嘉
田培%潘成忠%許新宜%楊帆%李長嘉
전배%반성충%허신의%양범%리장가
坡面流%空间变异%流速%侵蚀%山坡
坡麵流%空間變異%流速%侵蝕%山坡
파면류%공간변이%류속%침식%산파
overland flow%spatial variability%velocity%erosion%hillslope
在野外放水试验条件下,利用染色法和侵蚀针法分别观测坡面流速和侵蚀产沙空间变异性。结果表明,坡面各横向断面的流速与距坡顶距离之间呈正相关,且相关性随流量增大逐渐变得显著,纵向断面流速的变异程度明显强于横向断面。总体上,上、下坡位侵蚀程度较重,而中坡位最轻;小流量时沉积作用明显,大流量时距坡顶0~2m范围为净侵蚀区;各坡段侵蚀量与其距坡顶距离之间呈负相关;发生泥沙沉积部位随流量增大逐渐下移,细沟侵蚀量占坡面总侵蚀量的比例随流量增大不断增加。试验条件下流速为0?30 m/s时,细沟侵蚀产沙大于细沟间侵蚀,且坡面侵蚀量迅速增大。随流量增大,流速和侵蚀产沙量呈增大趋势;但在流量较大时,坡面各坡位侵蚀量与流速呈负相关,这可能与坡面中下部位粗颗粒泥沙沉积以及含沙水流的挟沙能力基本达到饱和有关。
在野外放水試驗條件下,利用染色法和侵蝕針法分彆觀測坡麵流速和侵蝕產沙空間變異性。結果錶明,坡麵各橫嚮斷麵的流速與距坡頂距離之間呈正相關,且相關性隨流量增大逐漸變得顯著,縱嚮斷麵流速的變異程度明顯彊于橫嚮斷麵。總體上,上、下坡位侵蝕程度較重,而中坡位最輕;小流量時沉積作用明顯,大流量時距坡頂0~2m範圍為淨侵蝕區;各坡段侵蝕量與其距坡頂距離之間呈負相關;髮生泥沙沉積部位隨流量增大逐漸下移,細溝侵蝕量佔坡麵總侵蝕量的比例隨流量增大不斷增加。試驗條件下流速為0?30 m/s時,細溝侵蝕產沙大于細溝間侵蝕,且坡麵侵蝕量迅速增大。隨流量增大,流速和侵蝕產沙量呈增大趨勢;但在流量較大時,坡麵各坡位侵蝕量與流速呈負相關,這可能與坡麵中下部位粗顆粒泥沙沉積以及含沙水流的挾沙能力基本達到飽和有關。
재야외방수시험조건하,이용염색법화침식침법분별관측파면류속화침식산사공간변이성。결과표명,파면각횡향단면적류속여거파정거리지간정정상관,차상관성수류량증대축점변득현저,종향단면류속적변이정도명현강우횡향단면。총체상,상、하파위침식정도교중,이중파위최경;소류량시침적작용명현,대류량시거파정0~2m범위위정침식구;각파단침식량여기거파정거리지간정부상관;발생니사침적부위수류량증대축점하이,세구침식량점파면총침식량적비례수류량증대불단증가。시험조건하류속위0?30 m/s시,세구침식산사대우세구간침식,차파면침식량신속증대。수류량증대,류속화침식산사량정증대추세;단재류량교대시,파면각파위침식량여류속정부상관,저가능여파면중하부위조과립니사침적이급함사수류적협사능력기본체도포화유관。
The spatial variability of overland flow velocity and soil erosion, and their relationship under different dis?charges, were investigated using a field runoff plot combined with the erosion pins. There exists a positive correlation between flow velocity and the distance from the top of slope, with the correlation becoming more significant as dis?charge increased. Variability of velocity at each cross section was stronger than that of the lateral section. The eroded sediment yield at the top or bottom of slope was greater than those at the middle. Sediment deposition clearly occurred for small flow discharge, and for high flows net erosion dominated the section of 0—2 m from the top of the slope. As flow discharge increased, the deposition zone gradually shifted down, and the proportion of rill erosion to the total a?mount of erosion increased. When overland flow velocity was greater than 0?30 m/s, the amount of rill erosion excee?ded that of inter?rill erosion, and the erosion amount of the whole slope increased rapidly. As flow discharge in?creased, the overland flow velocity and erosion amount also increased. However, under the same slope, greater over?land flow velocity corresponding to the down?slope tended to generate smaller erosion sediment yield, which may be at?tributed to the deposition of coarse sediment and the almost saturated sediment carrying capacity at the down?slope.