水科学进展2017，Vol.28Issue(5)：720-728,9.DOI:10.14042/j.cnki.32.1309.2017.05.009
人工掏挖坡面侵蚀微地貌演化及其水力学特性分析
Microtopography evolution of artificial digging and analysis of hydraulic characteristics
摘要
Abstract
Artificial digging was accomplished comprehensively in the Loess Plateau region during summer fallow till-age period. In order to elucidate the evolution processes on erosion as well as the flow hydraulic characteristics of its complicated slope surface under the condition of continuous rainfall, this study utilizes 3-D Laser Scanner and ArcGIS. They were employed to investigate the microtopography evolution process and hydraulic characteristics under intermit-tent simulated rainfall, following which it offers theoretical basis for tillage practices. The results demonstrate the fol-lowing:① There are three processes which are splash erosion and sheet erosion stage, the formation of rill stage and the developing of rill stage. The rill density, average depth, maximum rill length and depth increased by 1. 42, 1. 72, 15. 57 and 3. 18 times as against initial rill forming stage with rainfall.②The initial surface roughness of artificial dig-ging is 1. 706 which decreased linearly to 1. 488 with the rainfall. In the process of accumulated rainfall reaching 81 mm, the runoff and sediment yield increased slowly with the decline of roughness, but increased dramatically later.③ The flow velocity with fluctuation increased after the rill shaping, and the flow advanced from laminar to turbulent flow speedily, but keeping the subcritical flow all the way. Under the effect of surface roughness, the flow resistance comprised of grain resistance, rain resistance and form resistance which decreased with the rainfall duration, where the form resistance took the most significant position during the entire process. The slope surface of artificial digging might have a positive impact on soil and water conservation under the rainfall intensity of 1. 5 mm/min when the rain-fall is within 80 mm, but it may prone to suffer rill erosion under continuous extreme rainfall.关键词
人工掏挖/侵蚀过程/水力学参数/间歇降雨Key words
artificial digging/erosion process/hydraulic characteristic/intermittent simulated rainfall分类
农业科技引用本文复制引用
孙立全,吴淑芳,郭慧莉,张永东..人工掏挖坡面侵蚀微地貌演化及其水力学特性分析[J].水科学进展,2017,28(5):720-728,9.基金项目
国家自然科学基金资助项目 ( 41671276) The study is financially supported by the National Natural Science Foundation of China ( No. 41671276) . （ 41671276）
