不同降雨强度及坡度条件下饱和紫色土坡面细沟形态特征

Morphological Characteristics of Rills on the Slope Surface of Saturated Purple Soil Under Different Rainfall Intensities and Slopes

坡面细沟形态特征的定量分析是研究细沟侵蚀的基础。通过设计3种降雨强度(30,60,90 mm/h)和5种坡度(2°,5°,10°,15°,20°)组合条件下的人工降雨模拟试验,定量研究饱和紫色土坡面降雨强度及坡度对细沟形态及其空间变化特征的影响。结果表明:饱和紫色土坡面细沟平均宽度、深度和细沟宽深比分别为3.44~9.64 cm、1.01~8.14 cm和1.18~3.87,细沟宽度和深度沿坡面从上至下整体均表现出先增大后减小的趋势,细沟宽深比沿坡面表现为上坡<中坡<下坡的变化特征。整体来看,坡面细沟宽度和深度均与降雨强度和坡度呈正相关关系,且降雨强度和坡度对坡面细沟宽度的影响相近,而坡度对细沟深度的影响较降雨强度更显著;细沟宽深比与降雨强度和坡度呈负相关关系,且坡度对坡面细沟宽深比的影响显著大于降雨强度的影响。研究结果对认识饱和土壤坡面细沟侵蚀形态变化规律、进一步探究坡面细沟发育过程具有重要参考价值。

Quantitative analysis of slope rill morphological characteristics is the basis of rill erosion research.The artificial rainfall simulation tests under the combinations of three rainfall intensities(30,60 and 90 mm/h)and five slopes(2°,5°,10°,15°and 20°)were conducted,and the effects of rainfall intensity and slope on rill morphology and its spatial change characteristics of saturated purple soil slope were quantitatively studied.The results showed that the average width,depth and ratio of width to depth of rill on the saturated purple soil slope was 3.44~9.64 cm,1.01~8.14 cm and 1.18~3.87,respectively.The width and depth of rill increased first and then decreased from top to bottom along the slope surface,and the ratio of rill width to depth of rill along the slope surface followed the order of upper<middle<lower.On the whole,the width and depth of the rill were positively correlated with rainfall intensity and slope,and the influence of rainfall intensity and slope on the rill width was similar,while the influence of slope on rill depth was more significant than that of rainfall intensity.The ratio of rill width to depth was negatively correlated with rainfall intensity and slope,and the influence of slope on the ratio of rill width to depth was significantly greater than that of rainfall intensity.Above all,this study has important reference value for understanding the change law of rill erosion morphology on saturated soil slope and further exploring the development process of rill on slope.