关中平原区细沟水流侵蚀产沙研究

为了研究关中平原区坡面细沟侵蚀过程,利用定水头冲刷试验,系统研究了6个坡度(2°、4°、6°、8°、10°、12°)、5个流量(8L/min、16L/min、24L/min、32L/min、40L/min)工况下的细沟水流含沙量及其与各水动力学间的耦合关系。结果表明:不同流量和坡度下,细沟断面流速随细沟断面的增加而呈波动性增加。断面流速与流量及断面呈显著性相关,而与坡度和平均含沙量相关性不大;不同流量和坡度条件下,含沙量随冲刷历时的增加,先急剧降低,然后呈微小波动趋势,最终归于稳定。含沙量与流量和坡度呈显著幂函数关系增加;挟沙饱和系数K变化范围为10.17~295.66,对应的不淤保证率约为73%。K随流量和坡度的增大逐渐增加,但增加的趋势逐渐减缓。由此可知,挟沙水流的剥蚀能力是有限度的。

Experimental study on rill flow erosion and sediment yield

Water scour experimental study on rill flow sediment concentration is conducted,by 6 slopes (2°,4°,6°,8°,10° and 12°),and 5 flows (8 L/min,16 L/min,24 L/min,32 L/min,40 L/min).Results show that sectional velocity increases with the increase of volatility in the cross section of the groove.The sectional velocity has extremely significant correlation with flow rate and the cross section,but no significant correlation with slope and sediment concentration.Under the condition of different flow discharge and slope,sediment concentration increased volatility after sharply reduced in the beginning,and stabilized finally.Sediment transport saturation coefficient K range with 10.17 ～ 295.66,corresponding nondeposit assurance rate is roughly 73％.Parameter K increases with the flow and slope,but increased gradually slowing down.As a result,erosion ability of sediment laden flow is limited.