风成沙最优振筛时间

Optimum Time of Sieving Aeolian Sand with a Mechanical Sieve Shaker

筛析法是测定沉积物颗粒组分的简单便捷方法,但关于振筛机对不同物料颗粒的最佳筛析时间少有报道。采用顶击式标准振筛机、1/2Φ间隔的套筛,开展了以风成沙为筛析样品、以筛析时间为变量的实验。结果表明:随着筛析时间增加,粒度参数的平均粒径和分选系数有增加且趋于平稳的趋势,但参数级别未发生改变;随筛析时间的增加,个别样品的偏度和峰度级别发生改变,其余均未改变;整体上,≥35目的筛网是决定1/2Φ间隔套筛最佳筛析时间的主要标准筛,但不同特性的风成沙颗粒对不同筛网的最佳筛析时间存在差异;为保证在筛析时间增加的过程中,粒度参数级别不再发生改变,且各筛网上的沙物质颗粒质量变化较小或趋于稳定,选取供试样品的平均最佳筛析时间作为风成沙颗粒筛析的最佳时间,建议风成沙颗粒的最佳筛析时间为14min。

The sieve analysis is a usual method for the classification of particle fractions, and the mechanical sieve shaker is widely used for sieve analysis. However, there are few studies on the optimum time of dif- ferent kinds of particle matters sieved by use of mechanical sieve shaker. In this paper, aeolian sand was se- lected as the experimental sample, and knockout vibrating sieve machine and a set of standard sieves at in- tervals of 1/2Ф were used and the sieving time was set as a variate in this test. The results showed that with the increase of sieving time, although the numbers of the parameters of mean grain size and sorting are in- creased and presented a stablized trend, the parameter level has not changed. Some individual parameters of skewness and kurtosis are changed with the sieving time, but the majority remain a same standard; Totally, the sieves whose mesh numbers are more than 35 are the main sieves which decide the optimum time of the set of standard sieves at intervals of 1/2~, but the optimum times of the different sieves for the different ae- olian sand samples are different. In order to ensure the level of grain size parameters no longer changed, and the weight of sand on all sieves changed a little or tended to be stable, this paper selected the average of optimum time of all samples, and 14 rain was suggested to be the optimum time of sieving aeolian sand.