紫色土细沟侵蚀输沙能力研究

Sediment Transport Capacity in Eroding Rill of Purple Soil Slope

本研究采用体积置换法获得的细沟水流含沙量随沟长变化的过程数据,估算得到不同水力条件下的最大含沙量,进而计算水流的输沙能力.实验采用不同坡度（5°,10°,15°,20°,25°）、流量（2,4,8min/L）,测量紫色土细沟侵蚀输沙数据,分别采用细沟侵蚀含沙量随沟长变化的输沙过程的实测和拟合最大含沙量、细沟侵蚀剥蚀率为0时的含沙量3种方法确定紫色土细沟水流的输沙能力.结果显示,输沙能力随流量呈线性增加,随坡度呈对数增大,流量较坡度对输沙能力的影响更大.同一坡度下,流量越大,输沙量趋于输沙能力所需的沟长越短;同一流量下,坡度5°~15°时,坡度越大,输沙量趋于输沙能力所需沟长越短,坡度15°~25°时,输沙量趋于输沙能力所需沟长随坡度增加变化不大.相关性分析可知,3种方法计算得到的输沙能力基本一致.摘要：本研究采用体积置换法获得的细沟水流舍沙量随沟长变化的过程数据，估算得到不同水力条件下的最大含沙量，进而计算水流的输沙能力．实验采用不同坡度（5°，10°，15°，20°，25°）、流量（2，4，8min／L），测量紫色土细沟侵蚀输沙数据，分别采用细沟侵蚀含沙量随沟长变化的输沙过程的实测和拟合最大含沙量、细沟侵蚀剥蚀率为0时的含沙量3种方法确定紫色土细沟水流的输沙能力．结果显示，榆沙能力随流量呈线性增加，随坡度呈对数增大，流量较坡度对输沙能力的影响更大．同一坡度下，流量越大，输沙量趋于输沙能力所需的沟长越短；同一流量下，坡度5°。～15°时，坡度越大，输沙量趋于榆沙能力所需沟长越短，坡度15°～25°时，输沙量趋于输沙能力所需沟长随坡度增加变化不大．相关性分析可知，3种方法计算得到的输沙能力基本一致．

This study uses the sediment load process data in the water flow along the eroding rill to esti- mate the maximum possible sediment concentration under different hydraulic conditions before the trans- port capacity was estimated. The sediment delivery data were obtained from laboratory experiments invol- ving three flow rates （2, 4, 8 L/min） and five slope gradients （5°, 10°, 15°, 20°, 25°）. Three methods were used to calculate the sediment transport capacity of rill flow, from the actually measured maximum sediment concentration, the fitted maximum value as well as that at zero detachment rate. The results showed that sediment transport capacity increased linearly with flow rate and exponentially with slope gra- dients. The flow rate had more profound impact on sediment transport capacity than the slope gradient. Under the same slope gradient, and the slope length for the sediment load to approach the sediment trans- port capacity became shorter with the increase in flow rate. Under the same flow rate, shorter rill length was needed for sediment load to approach the sediment transport capacity with the increased in slope gradi- ent between 5°°15°, and the rill length for sediment load to approach the sediment transport capacity did not vary much under slopes of 15°~25°. There was very good consistency among the fitting relationships of three methods of calculating the sediment transport capacity.