水保所知识产出(1956---)知识库

坡面水流输沙能力是土壤侵蚀模型的重要参数之一，也是土壤侵蚀精确预报的基础。该文选用多沙粗沙区典型
黄土（中值粒径d50=0.095 mm，d50′=0.04 mm）进行了坡度范围为7%～38.4%，单宽流量范围为0.000 14～0.005 26 m2/s
的水槽模拟输沙试验，经无量纲化处理后分析了坡面水流输沙能力与坡度和单宽流量以及输沙能力与各水流强度指标间
的耦合关系。结果表明：坡面水流输沙能力与坡度、单宽流量呈幂函数关系（R2=0.955），且单宽流量较坡度而言对输沙
能力的影响更为显著；含沙水流平均流速与坡度、流量呈幂函数关系；剪切力可以通过幂函数关系式预测坡面水流输沙
能力（R2=0.900，NSE=0.756 1）；水流功率、有效水流功率是比剪切力更好的预测因子，其中考虑临界水流功率W0=36.5，
水流功率与输沙能力幂函数关系（R2=0.950，NSE=0.978）最佳；单位水流功率并不能作为预测输沙能力的水流强度指标。
该文关于黄土丘陵沟壑区坡面水流输沙能力的研究为土壤侵蚀预测模型提供了新的方法。

Overland flow sediment transport capacity is one of the important parameters of soil erosion model, and it is also a
basis for accurate prediction of soil erosion. In this paper, the typical loess with two different median diameters (median size
d50=0.095 mm, d50′=0.04 mm) in the sandy and coarse sand area was used in the simulation experiment of sediment transport
capacity in the sink. The slope gradient range was from 7% to 38.4% and the unit discharge range was 0.000 14-0.005 26 m2/s.
After unqualified analysis, the coupling relationship between the sediment transport capacity and slope gradient, unit discharge
and the flow intensity indicators (the mean flow velocity, shear stress, unit stream power, stream power, effective stream
power) were analyzed. The results showed that the sediment transport capacity exhibited an increasing trend with increased
slope gradient and unit discharge, and the sediment transport capacity had a power function relation with the slope gradient and
the unit discharge (R2=0.955). The index of slope gradient was 1.086 and the index of unit discharge was 1.372. So, the unit
discharge had more significant impact on sediment transport capacity than slope gradient. Compared with Zhang’s, Wu’s, and
Mahoodabadi’s models, Zhang’s model had a basic trial of this research , and the results of Bing Wu's model were all less than
the measured values in this study, while Mahmoodabadi’s model was the opposite. The mean flow velocity could be predicted
by a power function of slope and flow, the relation between sediment transport capacity and mean velocity was also a power
function relation ,with an index of 1.9072 (R2=0.857 3, Nash-Sutcliffe coefficient NSE=0.879 5). Because the mean flow
velocity was affected by many factors such as hydraulic parameters and surface conditions, the relationship between mean
flow velocity and sediment transport capacity could not be optimized. For example, the index was significantly (P<0.05)
affected by the median diameter of sediments. Shear stress could be used to predict the sediment transport capacity through
power function relations and the index was 2.498 1 (R2=0.900, NSE=0.756 1), which was not closely related to the influence of
soil particle viscosity. The stream power and effective stream power were better predictors than the shear stress, considering
the critical stream power W0=36.5. The power function relation of steam power and sediment transport capacity was the best
(R2=0.950, NSE=0.978), with an index of 0.920 8. Although the relationship between effective flow power and sediment
transport capacity was not optimal, it was still a content of further research. The unit stream power prediction model got poor
results for sediment transport capacity (R2=0.799 9, NSE =0.839 6), which was consistent with the results of Zhang’s, Bing
Wu’s and others’ studies. So, the unit stream power could not be used as a flow intensity to predict the sediment transport
capacity. Based on the dimensionless sediment transport capacity, the formula for calculating the flow capacity of the slope
was presented. This study of the sediment transport capacity in the Loess Hilly Gully Area provided a new method for the soil
erosion prediction model. It is of great scientific significance to predict slope erosion and to reveal the sediment transport
mechanism of slope.