引黄灌区非均匀沙的输送机理研究

Conveying Mechanism of Non-uniform Suspended Load in Irrigation Districts along the Lower Yellow River

非均匀沙输送机理是实现灌区泥沙合理配置与利用的关键技术之一。采用山东簸箕李灌区近20年来的泥沙观测资料,分析悬移质在渠道中的运动、冲淤规律。由于不同粒径的泥沙在水流中运动方式和沉积特点不一样,将非均匀沙按粒径粗细分组,研究了不同粒径泥沙的起动与止动、沉降与悬浮的差异,统计分析了分组沙的输沙能力、沿程衰减规律和上限平衡含沙量。结果表明,粗颗粒泥沙对流量因素敏感,若要使更多的粗颗粒泥沙实现长距离输送,应提高水流流速;细沙对流量因素的敏感度较粗沙小,同时挟沙力随细颗粒含量的增加而明显提高。

Conveying mechanism of non-uniform sediment is a key of rational utilization and optimizing distribution for sediment in irrigation districts rationally. Based on observational data in Bojili irrigation district for more than 20 years, transport and deposition laws of suspended sediment have be analyzed. Particles with different size have different characteristics of transportation and sedimentation in water flow. Thus non-uniform sand is grouped by particle size. The group carrying capacity and the maximum of equilibrium sediment concentration of non-uniform sand present in this paper. Result shows that the factor of flow discharge has greater impact on particles with coarse size than fine one. The best way conveying coarse particle to long distance is to increase velocity of flow.