砂卵石河流粗化完成后细沙补给对河床阻力的影响

发布时间：2018-04-23 11:39

  本文选题：细沙补给 + 粗化层　； 参考：《泥沙研究》2017年02期

【摘要】：结合Venditti关于细沙补给对河床活动性影响的分析,引用修正后的Einstein-Barbarossa方法对河床阻力进行划分,探讨了细沙补给对砂卵石河流冲刷粗化完成后河床阻力变化的影响。研究结果表明:在一定量细沙补给的条件下,沙粒阻力与床面阻力的比值先减小后增大,形状阻力与床面阻力的比值先增大后减小;水流克服表面阻力损失的能量随沙粒阻力减小而减少,进一步导致水流损失的机械能减小,河床上大颗粒泥沙获得的能量增大进而导致其活动性增强;河床上活动的泥沙颗粒与裸露大颗粒泥沙之间不断接触碰撞形成局部能量交换,裸露大颗粒泥沙通过水流方向的动量交换所产生的颗粒剪应力增大,这可能也是河床上大颗粒泥沙活动性增强的一个原因。
[Abstract]:Based on Venditti's analysis of the effect of fine sand recharge on river bed activity, the modified Einstein-Barbarossa method is used to divide the river bed resistance, and the influence of fine sand recharge on the river bed resistance after the completion of sand cobble erosion is discussed. The results show that under the condition of a certain amount of fine sand recharge, the ratio of sand resistance to bed resistance decreases first and then increases, and the ratio of shape resistance to bed resistance increases first and then decreases. The energy of water to overcome the surface resistance decreases with the decrease of sand resistance, which further leads to the decrease of the mechanical energy of water flow, and the increase of energy obtained by the large sediment on the riverbed, which leads to the increase of its activity. The local energy exchange is formed between the active sediment particles and the exposed large sediment on the riverbed, and the particle shear stress caused by the momentum exchange in the direction of the flow is increased. This may also be one of the reasons for the increase of sediment activity on the river bed.
【作者单位】： 四川大学水利水电学院水力学与山区河流开发保护国家重点实验室;
【基金】：国家重点研发计划项目课题(2016YFC0402302) 国家自然科学基金重点基金项目(51539007)
【分类号】：TV143
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本文编号：1791805