基于数据拟合分析坡面土壤侵蚀的临界坡度

Analysis of Critical Slope of Slope Soil Erosion Based on Data Fitting

通过不同雨强、坡度的多段模拟降雨实验,将坡度与坡面侵蚀模数进行二次多项式拟合,求得不同条件下坡面侵蚀的临界坡度。实验结果表明,临界坡度会随着雨强、降雨历时的变化而产生规律性变化。雨强越大,临界坡度越大,对坡面侵蚀临界坡度的影响越强烈;降雨历时增加,坡面侵蚀的临界坡度也随之增大,雨强越大,临界坡度增速越快,且增速拐点出现越早。在坡面侵蚀初期,坡度增加加强了坡面径流对坡面泥沙的搬运作用,减弱了坡面的溅蚀作用,使得在一定坡度范围内坡度大的坡面细沟侵蚀开始时间晚于坡度小的坡面,这是临界坡度产生的原因之一。随着坡面侵蚀过程的发展,坡面侵蚀主要发生于细沟的边缘、侧壁和底部,不同坡度坡面单位时间内的侵蚀模数差值减少且趋于稳定,坡度对于侵蚀模数的影响逐渐减小,临界坡度逐渐消失。该研究可为完善黄土区的土壤侵蚀机理提供理论依据。

Through multi-stage simulated rainfall experiments with different rain intensities and slopes,the slope and slope erosion modulus are fitted with quadratic polynomials to obtain the critical slope of slope erosion under different conditions.The experimental results show that the critical slope will change regularly with the change of rainfall intensity and rainfall duration.The greater the rain intensity,the greater the critical slope,and the stronger the impact on the critical slope of slope erosion.As the rainfall duration increases,the critical slope of slope erosion also increases.The greater the rain intensity,the faster the critical slope growth rate and the earlier the inflection point of the growth rate appears.In the initial stage of slope erosion,the slope increase strengthens the transport effect of slope runoff on the slope surface sediment and weakens the splash erosion effect of the slope surface,so that within a certain slope range,the onset of rill erosion on the slope surface with a large slope is later than the slope slope,which is one of the reasons for the critical slope.With the development of slope erosion process,slope erosion mainly occurs on the edges,sidewalls and bottom of rills.The difference in erosion modulus per unit time of slopes with different slopes decreases and tends to stabilize.The impact gradually decreases,and the critical slope gradually disappears.This study can provide a theoretical basis for improving the mechanism of soil erosion in the loess area.