砂礫河川の掃流砂に関する基礎的研究

Abstract

The purpose of this study is to make clear the mechanics of sand transport and toestimate its rate in a gravel river which consists of graded bed material with largestandard deviation. Field measurements were carried out in the Yasu River in flood seasonby the tracer method which offers a unique approach for studing the motion of discretesand grains. Characteristics of bed load on a gravel bed such as the effect of longitudinalstrips which are formed on it on the rate of bed load and the influence of secondaryflow to the tractive force were studied by detailed experiments and theoretical analysis.A proposed method of estimating the rate of bed load in a gravel river is verified withthe data on the basis of effective tractive force and efficient width.