管道压力与水深对黏性泥沙起动影响分析

发布时间：2018-08-12 14:41

【摘要】：有压管道中固结黏性泥沙起动试验的结果虽然能在明渠中推广,但在实际的压力管流和明渠流中,影响黏性泥沙起动的因素却不同。为更深入地研究黏性泥沙在明渠与管道中起动的异同,探究压力管道及水深因素对黏性泥沙起动的影响,从受力分析的角度出发推导出了黏性泥沙起动底部作用流速公式,但泥沙起动时底部流速较难测得,一般在实际生产和研究中用断面平均流速或起动切应力作为研究指标。将有压管道和明渠流的流速分布引入,确定了两种情况下起动作用流速与断面平均流速之间的关系,推导出起动流速公式与起动切应力公式,对公式拟合验证后得出结论:有压管道中,在泥沙淤积固结初期,黏结力对黏性泥沙的起动影响不显著,阻碍黏性泥沙起动的主要因素为管道压力,在后期,黏性泥沙黏结力增强,对其起动的影响增大。在明渠大水深条件下,相对水深变化小,不是影响黏性泥沙起动的主要原因,然而在明渠水槽试验中,相对水深对黏性泥沙起动的影响表现较为显著。在明渠中,水深的增大改变了微团所受薄膜水附加压力,起动流速和起动切应力随水深的增大而增大。
[Abstract]:Although the results of incipient tests of consolidated cohesive sediment in pressurized pipes can be generalized in open channels, the factors affecting incipient motion of cohesive sediment are different in actual pressure pipes and open channels. From the point of view of force analysis, the formula of starting bottom velocity of viscous sediment is deduced. However, it is difficult to measure the starting bottom velocity of viscous sediment. The relationship between the action velocity and the average cross-section velocity is deduced. The formula of starting velocity and the formula of starting shear stress are deduced and verified. It is concluded that the cohesive force has no significant effect on the start-up of cohesive sediment at the initial stage of sedimentation and consolidation in pressurized pipelines. In open channel, the change of relative depth is small, which is not the main reason to affect the incipient motion of viscous sediment. However, in open channel flume test, the effect of relative depth on incipient motion of viscous sediment is more significant. In open channel, the increase of water depth changes the film of micro-aggregates. Water additional pressure, starting velocity and starting shear stress increase with the increase of water depth.
【作者单位】：武汉大学水利水电学院;
【基金】：国家自然科学基金项目“旱涝急转发生机理与减灾方法研究”(51339004)
【分类号】：TV142.1

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