水槽中的非均匀沙起动流速研究

Study on Incipient Velocity of Non-uniform Sediment in Channel

基于泥沙起动的已有研究成果,采用起动流速统一表达式回归分析了多份试验资料,探讨了起动流速公式中起动系数的取值范围。考虑到非均匀沙之间的荫蔽作用对泥沙起动规律的影响,在泥沙粒径计算公式中引入荫蔽参数,分析了不同水槽试验资料中荫蔽参数的取值。对水槽试验非均匀沙起动流速的计算值与实测值资料的比较研究表明,起动系数一般为4.1～5.3;初始松散床面泥沙时荫蔽参数较小,可取0.2,但能否应用于山区天然河流中还有待进一步研究。

Based on the existing achievements in the incipient of sediment,unified incipient velocity formula is adopted to regression analysis of multi-experimental data and the range of incipient coefficient K in incipient velocity formula is discussed.Taking into account the impact of hiding,coefficient H in the formula is used to compute equivalent grain size and the value of H in different flume experiments is also analyzed.The comparative study of the experiment data and the calculated data from different flume experiments show that the value K of flume is in the range of 4.1 to 5.3;for the loose sediment of the incipient bed in flume experiment,the coefficient H should be small and it can be given 0.2;however,further study should be taken on if this data can be applied to natural rivers in mountainous areas.