关键词: 卵砾石, 边坡, 附加重力, 起动流速

Abstract: Aiming at the transporting characteristics of gravel sediment in low water and urgent shoal in mountainous rivers, it is found that incipient motion first starts at the foot of the slopes through the experiment observertions of the gravel on the slopes and theoretical analysis of the phenomenon. According to the gravel sediments stress state at the foot of the slopes, a rolling model is adopted to conduct a theoretic deduction; and the bottom velocity, drag coefficient, gravel underwater grav- ity and the impact of additional gravity are taken into account; then the incipient motion flow formula at the foot of the slopes is deduced, which relates to the slope gradient. Through the flume experiment, the gravel sediment incipient motion flow formula at the foot of the slopes is fitted out, and a comparision with Shamo Fu formula is made.

Key words: gravel sediment , slope , additional gravity , incipient motion flow ;