唐家山堰塞湖下游河床泥沙起动流速研究  

Study on the Incipient Velocity of Tangjiashan Barrier Lake Downstream Area Sediment

作　　者：杨奉广[1] 刘兴年[1] 黄尔[1] 杨克君[1] 曹叔尤[1] 

机构地区：[1]四川大学水力学与山区河流开发保护国家重点实验室,四川成都610065

出　　处：《四川大学学报（工程科学版）》2009年第3期84-89,共6页Journal of Sichuan University (Engineering Science Edition)

基　　金：国家973计划资助项目(2008CB425803);国家自然科学基金重点项目(50739002)

摘　　要：对均匀沙在陡坡上的起动机理作了分析。利用几何关系对均匀沙的暴露度概率密度函数进行修正,修正后的概率密度函数随着相对暴露度的变化而变化,并且有实验数据的间接支持。运用概率论与力学相结合的方法,以相对暴露度为基础,导出了泥沙颗粒力臂的数学期望,进而导出了考虑均匀沙隐暴效应的起动概率表达式。在起动概率的基础上建立了陡坡上均匀沙的起动流速公式。通过已有的陡坡均匀沙起动流速试验数据,确定了计算公式的参数。野外资料表明所得公式同时也适用缓坡的起动流速。分析表明:随着冲刷的进行,唐家山堰塞湖下游河床坡度变缓,泥沙起动流速变大。从而抑制河床的变形。The incipient motion of uniform sediment on non-horizontal slope was theoretically studied.Firstly,a correction of Probability Density Function（PDF） of hiding and exposure degree of uniform sediment was developed based on the geometric relation.Based on the method of probability theory combined with mechanics,the mean of sediment particle＇s force arm and the expression for the probability of incipient motion were derived.Once the incipient probability was developed,the incipient velocity can be determined.From the existing experiment data for the incipient velocity of uniform sediment on non-horizontal slope,the coefficients in the computing formula were determined and the formula derived can also fit the field data for horizontal slope condition.The analysis based on the formula developed showed that the incipient velocity of sediment at Tangjiashan Barrier Lake downstream area increases with the bed slope decrease because of the existence of scour.

关 键 词：唐家山堰塞湖 起动流速 均匀沙 陡坡 缓坡 

分 类 号：TV142.1[水利工程—水力学及河流动力学]