Study on formula of incipient velocity of sediment in model test

The analysis on current used formulas for determining the incipient velocity of sediment for model test indicates that the calculated velocity always higher than that obtained from experiment.A universal formula for improving the calculation accuracy is proposed,in which the parameters are determined according to the property and size of the sediment.The validity of the formula is verified by a lot of experimental data.The further investigation shows that the incipient velocity varies with the starting states of sediment.It includes the states of single sediment grain begin to move,a few of sediments starting to move and a lot of sediments starting to move.The formulas for determining the incipient velocity of different starting states are suggested.