黄土缓坡片蚀过程及其水力参数适宜性试验研究  

Experimental study on sheet erosion process of loess and its suitability of hydraulic parameters on gentle slopes

作　　者：和继军[1,2] 王硕[1,3] 蔡强国[4,5] 孙莉英 黎雪晴[1,3] HE Jijun;WANG Shuo;CAI Qiangguo;SUN Liying;LI Xueqing(State Key Laboratory of Urban Environmental Processes and Numerical Simulation,Capital Normal University,Beijing 100048,China;State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Water and Soil Conservation,Chinese Academy of Sciences and Ministry of Water Resources,Yangling 712100,China;Resources Environment and GIS Key Laboratory of Beijing,Capital Normal University,Beijing 100048,China;Key Laboratory of Water Cycle and Related Land Surface Processes,Institute of Geographical Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China;College of Resources and Environment,University Chinese Academy of Sciences,Beijing 100101,China)

机构地区：[1]首都师范大学城市环境过程和数字模拟国家重点试验室培育基地,北京100048 [2]中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨凌712100 [3]首都师范大学北京资源环境与GIS重点试验室,北京100048 [4]中国科学院地理科学与资源研究所陆地水循环与地表过程重点试验室,北京100101 [5]中国科学院大学资源与环境学院,北京100101

出　　处：《水科学进展》2021年第1期97-108,共12页Advances in Water Science

基　　金：国家自然科学基金资助项目(41771314;41401302)。

摘　　要：为确定黄土缓坡片蚀过程中侵蚀限制条件的变化及水力参数的适宜性,采用模拟降雨试验,在60 mm/h雨强、3种坡度(7.5°、10°、15°)和2种坡长(5 m和10 m)条件下,验证含沙量作为表征参量判定片蚀过程侵蚀限制条件的可行性,提出检验水力参数与产沙量作用关系适宜性的评价方法。结果表明:(1)依据含沙量随径流的变化规律,片蚀过程依次经历输沙能力限制阶段、剥蚀能力限制阶段Ⅰ和剥蚀能力限制阶段Ⅱ共3个侵蚀阶段,其中剥蚀能力限制阶段Ⅰ的侵蚀量占绝对优势。(2)从水力参数的适宜性来看,径流功率和雷诺数均能很好地表征与产沙量的关系,径流剪切力和弗劳德数则不能有效反映与产沙量的关系。(3)在不同侵蚀限制阶段,径流功率和雷诺数与产沙量的作用关系是不同的。输沙能力限制阶段和剥蚀能力限制阶段Ⅱ时,径流功率和雷诺数与产沙量分别呈指数关系和线性正相关关系;剥蚀能力限制阶段Ⅰ时,该2种水力参数均与产沙量呈线性负相关关系,但作用关系不唯一,且存在雷诺数临界值,即在输沙能力限制阶段和剥蚀能力限制阶段Ⅱ,径流功率和雷诺数与产沙量的作用关系不受坡长效应影响;在剥蚀能力限制阶段Ⅰ,需要同时考虑坡长和雷诺数临界值的共同影响。该研究结果可为深入理解片蚀过程的复杂性提供参考依据。In order to determine erosion-limited conditions and the suitability of hydraulic parameters in sheet erosion of loess gentle slope,simulated rainfall test was used in this study,under condition of 60 mm/h rainfall intensity,3 slopes(7.5°,10°,15°)and 2 slope lengths(5 m and 10 m),to verify the feasibility of sediment concentration as a characterization parameter to determine the erosion-limited conditions in the process of sheet erosion,and to propose an evaluation method to test the suitability of the relationship between hydraulic parameters and sediment yield.The test results showed that sheet erosion process could be divided into three erosion stages:transport-limited stage,detachment-limited stage I and detachment-limited stage II according to the change of sediment concentration with runoff,and the amount of erosion in detachment-limited stage I was dominant absolutely.For the suitability of hydraulic parameters,both stream power and Reynolds number could well characterize the relationship with sediment yield,while flow shear stress and Froude number could not effectively reflect the relationship with sediment yield.In different erosion-limited stages,steam power and Reynolds number have different relationship with sediment yield.In the transport-limited stage and detachment-limited stage II,steam power and Reynolds number showed exponential and linear positive correlation with sediment yield,respectively.In the detachment-limited stage I,stream power and Reynolds number had a linear negative correlation with sediment yield,but the interaction was not unique,with different slope length and Reynolds number critical value.That is,in the transport-limited stage and detachment-limited stage II,the relationship between stream power,the Reynolds number and the sediment yield was not affected by the effect of slope length;in the detachment-limited stage I,the joint influence of slope length and the critical value of Reynolds number should be considered simultaneously.The results of this study can provide valuab

关 键 词：片状侵蚀 侵蚀限制条件 径流功率 产沙量 雷诺数 

分 类 号：S157.1[农业科学—土壤学]