Sediment Transport Processes in Rivers

山区溪流具有坡度大、粒度大、流域面积小等特点。因此，泥沙运动的机制是非常复杂的，如群体运动或单个颗粒运动的现象。在这项研究中，选择了三个主题，分别是剪应力分布、推移质和悬移质与混合料的阶跃塘形态和泥沙运动之间的关系。研究结果表明：(1)建立了直槽断面剪应力分布的理论计算方法，并通过试验研究了阶梯形水槽床面剪应力分布规律。(2)建立了评价输沙现象的数学模型。利用该模型对输沙泥沙和底质泥沙的输沙率和泥沙粒度分布进行了数值预报，并与水槽资料进行了比较。这些结果似乎满足了本研究的目的。

Mountain streams are characterized by such features as steep slope,a wide range of grain sizes, and small drainage area. Mechanisms of sediment transportation, therefore, are very complex, as seen in the phenomena of mass movement or individual grain motion. In this study, three subjects which are concerning the shear stress distribution, bed load and suspended load in terms of relation between step-pool morphology and sediment movement of mixtures are chosen for consideration. The results of the present study show(1) A theoretical method to calculate the shear stress distribution in cross section of straight channel is developed, and in addition the pattern of shear stress distribution along the flume bed with step-pool morphology is investigated experimentally.(2) A mathematical model to evaluate the sediment transport phenomena is presented. Numerical predictions are made with the model for sediment transport rates and sediment size distributions of the transported sediment as well as bed sediment and are compared with the flume data. These results appear to satisfy the aim of the present study.