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Effects of sediment load on the abrasion of soil aggregate and hydraulic parameters in experimental overland flow
Journal of Integrative Agriculture ( IF 4.6 ) Pub Date : 2020-03-09 , DOI: 10.1016/s2095-3119(19)62719-x
Jun-guang WANG , Bing YU , Shi-min NI , Zhong-lu GUO , Chong-fa CAI

The breakdown of soil aggregates under rainfall and their abrasion in overland flow are important processes in water erosion due to the production of more fine and transportable particles and, the subsequent significant effect on the erosion intensity. Currently, little is known about the effects of sediment load on the soil aggregate abrasion and the relationship of this abrasion with some related hydraulic parameters. Here, the potential effects of sediment load on soil aggregate abrasion and hydraulic parameters in overland flow were investigated through a series of experiments in a 3.8-m-long hydraulic flume at the slope gradients of 8.7 and 26.8%, unit flow discharges from 2×10−3 to 6×10−3 m2 s−1, and the sediment concentration from 0 to 110 kg m−3. All the aggregates from Ultisols developed Quaternary red clay, Central China. The results indicated that discharge had the most significant (P>0.01) effect on the aggregates abrasion with the contributions of 58.76 and 60.34%, followed by sediment feed rate, with contributions of 39.66 and 34.12% at the slope gradients of 8.7 and 26.8%, respectively. The abrasion degree of aggregates was found to increase as a power function of the sediment concentration. Meanwhile, the flow depth, friction factor, and shear stress increased as a power function along with the increase of sediment concentration at different slope gradients and discharges. Reynolds number was obviously affected by sediment concentration and it decreased as sediment concentration increased. The ratio of the residual weight to the initial weight of soil aggregates (Wr/Wi) was found to increase as the linear function with an increasing flow depth (P=0.008) or Reynolds number (P=0.002) in the sediment-laden flow. The Wr/Wi values followed a power function decrease with increasing friction factor or shear stress in the sediment-laden flow, indicating that friction factor is the best hydraulic parameter for prediction of soil aggregate abrasion under different sediment load conditions. The information regarding the soil aggregate abrasion under various sediment load conditions can facilitate soil process-based erosion modeling.



中文翻译:

实验性陆流中泥沙负荷对土壤团聚体磨损和水力参数的影响

降雨条件下土壤团聚体的分解及其在陆流中的磨损是水蚀的重要过程,这是由于产生了更细,更易运输的颗粒,以及随后对侵蚀强度的重大影响。目前,关于泥沙负荷对土壤团聚体磨蚀的影响以及这种磨蚀与一些相关水力参数之间的关系知之甚少。在这里,通过一系列实验,在3.8 m长的水槽中,以坡度8.7和26.8%进行了一系列实验,研究了底泥负荷对土壤团聚体磨蚀和水力参数的潜在影响,单位流量从2x 10 -3至6×10 -3 m 2 s -1,沉积物浓度为0至110 kg m -3。Ultisols的所有骨料都发育了华中第四纪红土。结果表明,放电具有最大的显着性(P> 0.01)对骨料磨损的影响,贡献率为58.76和60.34%,其次是沉积物进料率,在坡度为8.7和26.8%时分别为39.66和34.12%。发现聚集体的磨损程度随着沉积物浓度的幂函数而增加。同时,在不同的坡度梯度和流量下,水深,摩擦系数和切应力作为幂函数随沉积物浓度的增加而增加。雷诺数明显受沉积物浓度的影响,随沉积物浓度的增加而降低。发现土壤团聚体的剩余重量与初始重量之比(Wr / Wi)随着线性关系随流深(P = 0.008)或雷诺数(P = 0.002)。Wr / Wi值跟随幂函数随含沙量增加的摩擦系数或切应力的增加而减小,表明摩擦系数是预测不同沉积物负荷条件下土壤团聚体磨损的最佳水力参数。有关在各种沉积物负荷条件下土壤团聚体磨损的信息可以促进基于土壤过程的侵蚀建模。

更新日期:2020-03-09
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