降雨对坡面薄层水流泥沙起动的影响  

Effect of Rainfall on Sediment Incipient Motion of Overland Flow

作　　者：赵春红[1] 高建恩[1,2,3] 王宏杰[3] 邵辉[1] 许秀泉[2] 

机构地区：[1]西北农林科技大学资源环境学院,陕西杨凌712100 [2]中国科学院水利部水土保持研究所,陕西杨凌712100 [3]西北农林科技大学水利与建筑工程学院,陕西杨凌712100

出　　处：《应用基础与工程科学学报》2013年第6期1057-1069,共13页Journal of Basic Science and Engineering

基　　金：国家自然科学基金"复杂下垫面暴雨径流侵蚀相似性模拟实验研究"(41371276);"十二五"国家科技支撑计划课题(2011BAD31B05);国家水体污染控制与治理科技重大专项(2009ZX07212-002-003-002);中国科学院水利部水土保持研究所知识创新工程专项(A315021304)

摘　　要：针对降雨条件下坡面泥沙起动研究不足,基于动量守恒原理,导出了雨滴对坡面泥沙颗粒作用力的数学表达式,采用滑动起动模式,建立了适用于降雨条件下坡面薄层水流的非黏性泥沙起动流速公式.公式系数通过室内和野外实测资料率定获得.结果表明降雨对坡面泥沙起动具有促进作用,其作用大小主要与降雨强度(i)、泥沙粒径(d)及水深与雨滴直径比(h/d y)有关.雨强越大,泥沙越易起动,而泥沙粒径或h/d y越大,降雨的影响则越小.将该公式应用于降雨条件下坡面薄层水流泥沙搬运能力计算,计算值与实测值吻合较好.Understanding the sediment incipient condition from overland flow under rainfall impact is essential for soil erosion model development.A mathematical expression of raindrop impact stress on individual sediment particle was deduced based on the principle of conservation of momentum.Then a new incipient velocity formula for non-cohesive sediment from overland flow was proposed based on forces analysis and rainfall impact was taken into consideration by introducing the raindrop impact stress.The coefficients of the new formula were calibrated by the published data and the lab data from artificial rainfall experiment.Results indicate that rainfall impact can reduce the critical overland flow velocity and made the sediment particles easier to be entrained into motion.The rainfall impact largely depends on the rainfall intensity （i）,sediment particle diameter（d） and the ratio of flow depth to raindrop diameter（h/dy）.The larger the rainfall intensity,the easier the sediment starts to move,while the larger the sediment particle diameter or h/dy,the less influence the rainfall has.The critical velocity formula was applied in the prediction of sediment transport capacity of overland flow under rainfall impact and the simulation results agree well with the measured ones.

关 键 词：坡面流 雨滴作用力 非黏性泥沙 起动流速 公式应用 

分 类 号：S157.2[农业科学—土壤学]