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利用人工模拟降雨试验,定量研究不同降雨强度下20°坡面草地的减流减沙效应,探讨草被坡面固土作用的力学机制。结果表明:在45、87和127 mm/h降雨强度下,草地坡面土壤的平均入渗率是裸地坡面入渗率的2.1～4.2倍;与裸地相比,草地径流流速减少77.3%～79.8%,径流量减少51.9%～99.1%,产沙量减少93.6%～99.2%;从力学角度分析坡面土壤颗粒的受力情况,建立的坡面产沙量与径流切应力的关系模型可用于草被坡面土壤流失量预测;试验条件下,草地临界径流切应力值为2.857 N/m2,裸地临界径流切应力值为0.861 N/m2,坡面产沙量随径流切应力的增大而增大。研究结果对定量评价草被减流减沙作用和深化土壤侵蚀力学过程有一定的参考意义。
Simulated rainfall experiment was used to quantitatively study the effect of reducing flow and reducing sediment on 20 ° slope grassland under different rainfall intensities, and the mechanical mechanism of slope-fixing soil on grass slope was discussed. The results showed that the average soil infiltration rate of grassland was 2.1 ~ 4.2 times that of the bare land at rainfall intensities of 45, 87 and 127 mm / h. Compared with bare land, the runoff of grassland decreased by 77.3 % To 79.8%, the runoff decreased by 51.9% ~ 99.1%, and the sediment yield decreased by 93.6% ~ 99.2%. From the mechanical point of view, the force of soil particles on the slope surface was analyzed and the relationship between the sediment yield and the shear stress The model can be used to predict the amount of soil loss on the slopes of grassland. Under the experimental conditions, the critical shear stress of grassland is 2.857 N / m2, and the critical runoff shear stress of bare land is 0.861 N / m2. Increase and increase. The results of this study have certain reference value for the quantitative evaluation of grassland flow reduction and sediment reduction and soil erosion process.