黄土坡面薄层流产流过程试验研究

Experimental study on runoff dynamic processes on loess hillslope

薄层流径流过程是最基本的坡面水文过程,揭示黄土坡面薄层流产流过程机理对于认识坡面产流理论具有重要意义。试验采用人工模拟降雨试验方法,对黄土坡面薄层流产流过程进行研究,取得了如下结果：（1）坡面薄层流径流率随降雨历时的增长呈增加趋势,可用幂函数方程很好地描述,开始产流后的2-10 min内增加很快,以后逐渐趋于平缓、稳定;（2）不同坡度条件下,坡面薄层流径流深均随雨强的增大而呈显著增加,可用线性方程很好地表示;（3）不同雨强条件下,坡面薄层流径流深随坡度的变化趋势相似,皆可用对数线性方程描述;（4）不同雨强条件下,薄层流径流深随坡长增大总体呈增加趋势,可用倒数线性方程描述;（5）雨强、坡度、坡长对坡面薄层流径流深的综合影响可表述为三元线性经验方程,其中雨强的影响最大,坡度和坡长的影响小。

The runoff process of the sheet flow is the basic hydrologic process on the hillslope,and to reveal the mechanism of the runoff of the sheet flow is important for the understanding of the runoff theory on hillslope.With artificial simulation rainfall tests,runoff processes of the sheet flow on loess hillslope were studied and the following results were obtained：（1） The runoff rates varied with rainfall duration and their relationship could be described with power function.Runoff increased while rainfall duration increased,and the change was large in the first 2～10 minutes;after 10 minutes it trended to steady.（2） Under different slope gradients,runoff depth on the slope increased with rainfall intensities linearly,and the relationship could be described by linear equation.（3） Under different rainfall intensities,runoff depth on the slope varied similarly with soil gradients and could be described by log-linear equation.（4） Under different rainfall intensities,the relationship of the runoff depth and slope length could be described with reciprocal-linear equation.（5） The runoff depth statistical equations could be described by multiple linear equations,and rainfall intensity affected erosion modulus most greatly,followed by slope gradient and slope length.