农业机械学报2017，Vol.48Issue(4)：224-232,9.DOI:10.6041/j.issn.1000-1298.2017.04.029
不同土壤前期含水率和坡度下黄壤分离临界水动力特性
Critical Hydraulic Characteristics of Yellow Soil Detachment under Different Antecedent Soil Moisture Contents and Slope Gradients
摘要
Abstract
Critical hydraulic characteristics of soil detachability are essential factors for soil erosion predicting.There is still insufficient knowledge on key factors and governing mechanism of soil detachability,especially for various near-surface soil water conditions.The typical eroded yellow soil area in the upper and middle Yangtze River was taken as the research area.In order to illustrate the response of critical condition of soil detachment under different subsurface soil water conditions,scour flume was used to measure hydrodynamics parameters.Five antecedent soil moisture contents (5％ ～23％) and five slope gradients (1.0° ～ 10.0°) were designed.Results showed that critical flow velocity,flow depth and flow pattern of soil detachment all showed power function decreasing trends with the increase of slope gradient and antecedent soil moisture content.When the slope gradient was smaller than 5.0°,critical hydrodynamics parameters of soil detachment were influenced by coupling effects of slope gradient and antecedent soil moisture content;otherwise,it would be mainly influenced by slope gradient.It was also proposed that the simplified power function equation could be used accurately when slope gradient was larger than 5.0°.Most of the flow patterns belonged to laminar flow and subcritical flow.The slope gradient and antecedent soil moisture content played an important role in the overland flow Darcy-Weisbach friction factor.When Reynolds number and critical discharge per unit width were increased,the Darcy-Weisbach friction factor was decreased as power function.关键词
土壤分离/土壤前期含水率/坡度/临界水动力特性/黄壤Key words
soil detachment/antecedent soil moisture content/slope gradient/critical hydraulic characteristics/yellow soil分类
农业科技引用本文复制引用
王晨沣,王彬,王玉杰,王云琦,胡波,李世荣..不同土壤前期含水率和坡度下黄壤分离临界水动力特性[J].农业机械学报,2017,48(4):224-232,9.基金项目
国家自然科学基金项目(41401299) （41401299）
