压力管道与明渠中固结黏性泥沙起动对比分析

Comparative Study on Incipient Motion of Consolidated Cohesive Sediment in the Pressured Pipe Flow and Open Channel Flow

为探究有压管道中固结黏性泥沙起动试验的结果能否在明渠中推广,借鉴土力学研究成果建立黏性微团起动微观结构模式,对有压管流与明渠流中黏性微团进行受力分析,进而推导出2种情况下微团起动底部流速公式。对比公式得出2者在形式上相似,起动流速均与黏性微团相对干密度和水深压力项有关。通过抗冲性较差的黏性泥沙在明渠和压力管道中的同组对照试验对比,进一步得出2者差异较小,管道试验结果可以推广到一般明渠中。

In order to explore whether the results of consolidated cohesive sediment incipient motion test in pressured pipe flow can be applied in open channel flow, the microstructure model of cohesive microaggregate was established by referring to the soil mechanics research results. Bottom incipient velocity formula on both situation were derived by force analysis of the microaggregate. The comparison of the two formula shows that they are similar in form, and both related to relative dry density and the depth of water. Through the comparison of the control experiment with coarse grained cohesive sediment, the results show that the incipient shear stress in two experiments is close. The results of the pressured pile flow test can be extended to the general open channel flow.