不同级配砂砾石介质给水度的试验研究

Experimental Study on Specific Yield of the Sandy Gravel Media with Different Gradation

基于山西柳林段黄河河床自然堆积砂砾石介质的室内试验,以人工干预改善砂砾石介质的储水特性为目的,在分析其自然级配储水特性的基础上,研究了由同粒径组成的砂砾石介质和不同粒径级配砂砾石介质给水度的变化特性,建立了给水度与反映砂砾石级配特性的特征粒径指标的数学模型。结果表明,同径砂砾石介质的给水度随着砂砾石介质粒径组平均粒径的增大而增大,给水度与平均粒径间的关系较好地符合对数关系;砂砾石介质的级配对给水度有着明显的影响;在一定范围内给水度随不均匀系数的增大而减小,当不均匀系数大于某值后,又随不均匀系数的增大而增大,它们之间存在密切的二次多项式相关关系;用不均匀系数对给水度进行预测是可行的。

Based on laboratory test on the natural accumulated sandy grav＇el from the Yellow river riverbed in LiuLin county Shanxi province, in order to improve the storage characteristic of the natural accumulated sandy gravel artificially, on the basis of analyzing water storage characteristics of the natural gradation, the specific yield variation characteristics of the sandy gravel media with the same diameter particle and dif- ferent diameter particles were researched, and the relation between the specific yield and some feature di- ameter index which reflected sandy gravel gradation characteristics was established. The results showed that the specific yield of the sandy gravel media with same diameter increased with the growing of average diameter; the relationship between specific yield and average diameter accorded with logarithmic curve~ the specific yield was significantly affected by the gradation of sandy gravel. In a certain range the specific yield decreased with the increasing of the uniformity coefficient, then the specific yield increased with the in- creasing uniformity coefficient when the uniformity coefficient was above one value; a close quadratic mul- tinomial relationship existed between the specific yield and the uniformity coefficient, and it was feasible to predict the specific yield by uniformity coefficient.