变坡陡比降河道强输沙下泥沙淤积与水位激增的试验研究  

Experimental study on sediment deposition and water level surge under high sediment concentration in variable steep slope river

作　　者：李彬[1] 郭志学[1] 陈日东[1] 张斌[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：《泥沙研究》2015年第3期63-68,共6页Journal of Sediment Research

基　　金：国家科技支撑计划项目(2012BAB05B02);国家自然科学基金项目(50949057)

摘　　要：山洪常常挟带大量松散块体汇入山区性河道,使河流处于强输沙状态。强输沙水流进入中下游河段后,由于坡降变缓,会衍生出河床地形的淤积抬高,使水位大幅度的升高。通过变坡陡比降水槽,采用单因素控制法研究了强输沙条件下河床地形的冲淤发展及水位变化规律,并根据河流自动调整作用机理,分析了河道淤积发展传播规律,揭示了泥沙在山洪中的附加致灾作用。试验结果表明:上游陡坡河道的强输沙水流,进入下游较缓河段时,在床面可发生淤积,该淤积影响可快速向上游传播,导致河床大范围淤高。其淤积起始位置和淤高厚度与水流强度、含沙浓度等因素有关。更为严重的是,局部淤积发生后,床面比降的变化可能会改变局部河段的急流状态,使淤积锋面处发生水跃,从而显著提高洪水水位。试验发现当上游泥沙补给减弱后,淤积的床沙又快速被水流冲刷掉,使洪水之后很难发现河床淤积的痕迹。High concentration sediment could be carried into mountain streams by flash floods. Sediment will be deposited in the middle or lower reach, due to the slope becoming gentle, and further cause the water level rise suddenly. The influence of the reversible transmission of sediment deposition to water level is studied in this paper, and the experimental results are analyzed through the automatic adjustment mechanism of river. The results reveal that both the sediment deposition and the hydraulic jump contribute to the water level eleva- tion of river. The initial deposition position and thickness are related to flow and sediment concentration. The deposited sediment will be washed away soon after reducing sediment supply.

关 键 词：陡比降 强输沙 自动调整 淤积 水跃 

分 类 号：TV142.2[水利工程—水力学及河流动力学]