长江重庆河段卵砾石推移质无量纲输沙率研究

Analysis of dimensionless bed-load discharge of the Chongqing reach of the Yangtze River

针对长江上游重庆河段水面比降大、河床组成粒径粗、相对光滑度比较小等特点,收集河段内寸滩水文站47年实测卵石推移质输沙率资料和对应的水力参数作为研究基础资料,分析比较了5个经典公式计算的准确性。参照计算精度较高的Fredsoe公式,以水流强度Θ和泥沙起动临界水流强度Θc为主要参数建立并拟合了适合长江上游重庆河段的推移质输沙率计算式。分析比较表明,在计算重庆河段输沙强度时,该计算式的计算精度要高于经典公式和针对该河段的魏丽公式,能够很好地反映该河段实际的卵石推移质输移情况。

The Chongqing reach of the upper Yangtze River is characterized by large water surface slope, riverbed material armoring （coarse bed material） and less relative smoothness. In view of these special characteristics, 47 years measured data of cobble bed-load transport rate with the corresponding hydraulic parameters collected by Cuntan Hydrological Station have been taken as the basic data in analyzing and comparing the calculation accuracy of five classic formulae. In the light of Fredsoe （1976） formula having the higher calculation accuracy, taking 6） and θc as the main parameters, a formula is established and fitted suitable for calculating the bed-load transport rate in the Chongqing reach of the upper Yangtze River in this paper. It is shown from the analysis and comparison that the calculation accuracy of the formula is higher than that of the classic formula and Wei Li （2010） formula mainly aiming at the Chongqing reach when the intensity of bed-load transport of the Chongqing reach is calculated, and that this new formula can well reflect the reality of the cobble bed-load transport in the reach.