Author(s): Shengfa Yang; Xuhui Fu; Jiang Hu
Linked Author(s): Shengfa Yang, Xuhui Fu
Keywords: Gravel; Incipient motion drag force; Incipient motion velocity; Incipient motion flow power
Abstract: In this paper, 13 groups of gravel incipient motion experiment data are obtained and 50 groups of data from 7 researchers are collected. The data contain a wider range of slope (0. 05 – 20% ) and grain diameter (1. 8 - 45 mm). Comparison is made between the experiment data and the formulas of incipient motion drag force and incipient motion velocity, and the result demonstrates that the two types of incipient motion formulas fail to fully obey the gravel incipient motion law. By selecting the major factors which influence gravel movement and through dimensional analysis and relative analysis of experiment data, gravel incipient motion formula is modified in which the non-dimensional unit width discharge is inversely proportional to the slope. The formula corroborates an assumption proposed by Chien (1999) that gravel non-dimensional incipient motion flow power is a constant of 0. 09. Comparison is made between the experiment data and the four incipient motion formulas of unit width discharge such as incipient motion formula in this paper, Schoklitsch (1962) formula, Bettess (1984) formula and Bathurst (1987) formula, and the result demonstrates that the calculated value of incipient motion formula in this paper agree best with the measured value.
Year: 2013