论文部分内容阅读
研究细沟发育的形态演变规律是认识细沟发生机理的前提,本研究通过人工降雨与微地貌扫描相结合的方法,调查了紫色土坡耕地细沟发生过程的形态演变特征。采用三维激光扫描仪扫描不同降雨时段坡面,生成高精度坡面DEM图像,统计各时段不同坡段等高线偏离度,量算坡面凹陷区的表面积、周长、直径以及沟头下切深度;结果表明,等高线偏离度越大细沟发育越完全,有细沟发生坡面等高线偏离度是无细沟坡面的1倍以上;凹陷区的表面积、周长、直径相对于单位降雨量的扩展速率均在细沟贯穿时段出现最大值;跌坑位置与坡面水平起伏关系不明显,统计的3条沟头分别发育于水平方向起伏的最高点、中间点和低点;跌坑下切深度及其单位降雨量的扩展速率在跌坑贯穿形成细沟时段出现最大值,之后逐渐降低,说明跌坑的形成是细沟造床的关键。
Studying the morphological evolution of rill development is a prerequisite to recognize the mechanism of rill. In this study, the morphological evolution of the rill in purple soil was investigated through a combination of artificial rainfall and micro-topography. A 3D Laser Scanner was used to scan the slopes of different rainfall periods to generate DEM images of high precision slopes. The deviation of contour lines at different slopes was calculated, and the surface area, perimeter, diameter and depth of undercutting The results show that the greater the deviation of the contour line is, the more complete the development of the thin-walled groove is, and the deviation of the contour line of the slope where the thin-walled groove occurs is more than one times that of the non-thin grooved slope surface. The surface area, The maximum rate of rainfall extension occurred in the whole period of the ravines. The location of the drop pit had no obvious relationship with the horizontal fluctuation of the slope, and the three ditches of the statistics developed respectively at the highest point, the middle point and the low point of the horizontal undulation. The depth of undercutting and the rate of rainfall per unit expansion rate of the downhole occur at the maximum during the period when the downhole runs through the formation of the rill, and then gradually decrease, indicating that the formation of the downhole is the key to the development of the gully.