Study On Laws Of Incipient Motion Of Coarse Sediment

The incipient motion character of coarse sediment(D>2mm)is one of the most important problems in the field of sediment mechanics and river dynamics. So far, it did not achieve the desired results, because that is so difficult. On the basic of the comprehensive review of the study achievements for this problem in this article, with standards of incipient motion for coarse sediment , study on laws of incipient motion for coarse uniform and non-uniform sediment with flume data, which achieve from experiment of variable slope flume-28m and other researchers.Adopting Parker's standards of no-dimensional transport rate, there are 70 groups experiment of incipient motion for coarse uniform sediment, which achieved 9 groups incipient motion data include discharge and depth. Combing 9 groups of flume data and 38 groups of others, analyzing starting velocity, starting drag force and starting power, it is obvious to find that starting velocity and drag force do not convey the starting of coarse sediment. On the other hand, the dimensionless per unit width q c* is proportional to the reciprocal of slope J, it can express W c*=0.2.As coarse uniform sediment, there are 42 groups experiment of incipient motion for coarse no-uniform sediment, which achieved 30 groups incipient motion data. Refer to uniform sediment result, consider the hidden influence to sediment with bed material, which adds dimensionless parameter D , It obtains the dimensionless staring power for coarse no-uniform sediment:...