清水冲刷河床调整过程试验研究

通过沙质河床清水冲刷水槽试验,对河床纵剖面的调整、沙波尺度、粗化层厚度及其与沙波运动关系、粗化层级配、推移质级配等进行了观测分析,进一步揭示了清水冲刷,河床重建平衡的机理。水槽试验表明,沙质河床清水冲刷,上游河段比降调平,床沙粗化,沙波发育,河床阻力增大,水深增大,流速减小,导致河床供沙能力削弱,输沙能力降低,冲刷向不冲刷转化。

Study on the process of river-bed adjustment caused by clear water scouring

Based on the flume experiment of the clear water scouring at the sandy bed,the observation and analysis are carried out about the longitudinal profile adjustment,the scale of sand wave,the thickness of the bed materials armoring layer,the relationship between armoring bed materials layer and sand wave migration,the graduation of the bed materials armoring layer,bed load graduation etc.Then the mechanics of clear water souring and river-bed balance of reconstruction is revealed.The flume experiment shows that the slope of upper reaches is leveled,bed material is coarsened,sand wave is developed,bed resistance is increased,the water depth is deeper,the flow velocity is reduced with the clear water scouring.As a result the sand supply capacity of river is weakened and the sediment transport capacity is reduced,in a word,the rivers drive to equilibrium.