我国主要水蚀区缓坡坡面水流挟沙力差异研究

Study on the difference of sediment transport capacity of flow on gentle slope in major water erosion regions of China

我国主要水蚀区的土壤特性存在着较大的差异,这可能会导致坡面水流挟沙力的不同。然而,关于不同区域挟沙力特征的研究较为欠缺。在我国水蚀分区的基础上,以5个主要水蚀区典型土壤为研究对象,采用人工模拟定床放水试验,在不同坡度(3°~15°)和单宽流量(0.68×10^(-3)~5.40×10^(-3) m^(2)/s)下对所选土壤进行了坡面水流挟沙力测定。结果表明:西北黄土高原区黄绵土挟沙力最大,南方红壤丘陵区红壤挟沙力最小;黄绵土挟沙力对流量的变化最敏感,对坡度变化最为敏感的是红壤;不同的土壤类型对坡面水流挟沙力与流量以及坡度之间的关系会有影响。

There are great differences in soil characteristics in major water erosion regions in China, which may lead to the difference of sediment transport capacity of overland flow. However, the study on the characteristics of sediment transport capacity in different regions is relatively scarce. On the basis of water erosion zoning in China, typical soils in five main water erosion areas were used as research objects, and adopted an indoor artificial simulated runoff test on a fixed bed resistance to measure the sediment transport capacity of overland flow of selected soils with different slopes(3°~15°) and flow rates(0.68×10^(-3)~5.40×10^(-3)m^(2)·s;). The results showed that the measure transport capacity of soil in the Loess Plateau in northwestern China was the largest. The sediment transport capacity of loess soil was most sensitive to the change of discharge, while the red soil is most sensitive to the change of slope gradient. Different soil types influence on the relationship by sediment transport capacity, flow discharge and slope gradient.