【摘要】 采用一维稳态数学模型计算沿程水位.考虑河床组成物质沿河宽、沿深度和沿程的变化,将水流阻力分解为沙粒阻力、沙波阻力及河道形态阻力,提出了相应阻力系数的计算方法.根据垂线平均流速的横向分布,逐条垂线计算不冲粒径,以形成抗冲保护层作为控制条件,计算各条垂线处的冲刷深度,修改河床高程,并得到冲刷粗化以后的河床表层级配及断面平均粒径.对于给定的流量,求得冲刷粗化以后河道沿程的阻力系数、水位、流速及航运条件,以模拟卵石夹沙河床长期清水冲刷的情况.更多还原

【Abstract】 A one-dimensional mathematical model was used to calculate the drop of water elevations along a gravel bed river after a long-term clear water scouring. The composition of bed materials was taken into account both in longitudinal and transverse directions. The flow resistance before and after scouring was divided into three parts, such as; grain resistance; resistance of bed configuration and resistance for irregularity of river plane form. The method for calculating those resistances was presented in this paper. According to the transverse distribution of velocities obtained in the model and the composition of bed meterial; the critical diameter of unmovable particles and the scour depth at different verticals were determined. After that; the local bed elevations and the gradation; as well as the cross-sectional average size of bed material were obtained. For a certain flow discharge after scouring; the profile of water surface and river bed and the dimensions of navigation channel along the river course can be determined.更多还原