坡面径流阻力计算模式对比研究  

A comparative study on different roughness models of overland flow simulation

作　　者：胡鹏[1] 余明辉[1] HU Peng;YU Minghui(State Key Laboratory of Water Resources and Hydropower Engineering Sciences,Wuhan University,Wuhan 430072,China)

机构地区：[1]武汉大学水资源与水电工程科学国家重点实验室,湖北武汉430072

出　　处：《水利学报》2020年第1期14-22,共9页Journal of Hydraulic Engineering

基　　金：国家自然科学基金项目(11972265);国家重点研发计划项目(2016YFC0402604)。

摘　　要：坡面流是污染物迁移、土壤侵蚀、泥沙输移的主要动力因素,阻力系数是影响坡面流模拟的重要参数。为比较三种阻力计算模式(阻力系数为常数、以淹没度为变量的Lawrence模型和阻力分割模型)在裸坡、砾石覆盖坡面、植被覆盖坡面三种常见坡面上的适用程度,本文建立了坡面降雨径流模型,对不同类型坡面的产流进行了模拟。坡面径流模型采用扩散波模型,坡面降雨入渗模型采用考虑坡度影响的Green-Ampt模型,当存在植被时,考虑冠层降雨截留损失。结果表明:在裸坡上,三种阻力计算模式均适用;而在有砾石覆盖和植被覆盖的坡面上,考虑阻力系数时空变化的阻力分割模型模拟精度最高。阻力系数对坡面径流流量的影响在坡面汇流的涨水与退水阶段较大,而在稳定阶段很小。对有植被覆盖坡面,降雨强度存在阈值,大于阈值时,不同阻力模式对坡面流模拟结果影响甚微;反之,需选择合适的阻力计算模式,且坡长越长,坡度越缓,降雨强度阈值越大。Overland flow is the main agent for the transport and delivery of water,pollutants and soil parti⁃cles.Roughness is an important parameter which impacts overland flow simulation results.The three rough⁃ness models including constant roughness coefficient model,Lawrence model and roughness coefficient divid⁃ed model are compared in bare slope,stone covered slope and vegetation covered slope.The Rainfall-run⁃off Model which adopts the diffusive wave equation and Green-Ampt model considering slope effect is built to simulate runoff process.Plant canopy interception of rainfall is considered when vegetation exists.The analysis results indicate that the three roughness models are suitable for bare slope while roughness coeffi⁃cient divided model performs best on stone and vegetation covered slopes which accounts for the space and time variant resistance factor.The effect of roughness on flow hydrograph is mainly during the rising limb and falling limb.For vegetation covered slope,there exists threshold value of rainfall intensity When rain⁃fall intensity is larger than the threshold,the different roughness models have little impact on the simula⁃tion results.Otherwise,it is needed to choose the suitable roughness model.The threshold value is larger when the slope length is longer and the slope is smaller.

关 键 词：阻力系数 降雨径流模型 坡面径流模拟 降雨强度 

分 类 号：S715.3[农业科学—林学]