泥沙自然堆积孔隙率计算的试验研究

泥沙孔隙率是泥沙研究的一个重要物理量,确定泥沙孔隙率与粒径的定量表达式具有重要意义。通过室内试验,采用排水体积法测量不同粒径组泥沙、均匀沙、混合沙的自然堆积孔隙率,验证了细颗粒泥沙比粗颗粒泥沙孔隙率大的一般性结论,并通过试验结果分析与拟合,给出了均匀沙自然堆积孔隙率的经验公式。同时,运用圆球模拟泥沙颗粒的方法求得均匀沙的理论孔隙率,当均匀沙的中值粒径小于4.5mm时,圆球理论孔隙率与实测孔隙率的相对误差小于3%,得到的理论孔隙率较可靠。

Experimental Study on the Porosity of Sediment in Natural Deposition

The porosity is an important physical quantity in sedimentation studies. The porosity of sediment is almost limited to qualitative analysis and there is few study on the quantitative analysis on relation of sediment porosity and particle size. The drainage method in experiments is used to measure the natural deposition porosity of different size groups, uniform and mixed sediment. Results demonstrate that the porosity of fine sediments is generally higher than that of coarse sediments. Meanwhile an empirical formula of calculating the porosity of uniform was obtained by fitting the experimental data. The theoretical porosity of uniform sediment was derived by the packing of spheres to simulate the sediments. When the median size of uniform sediment is less than 4.5 mm, the theoretical porosity is reliable that the relative error between the theoretical and measured porosity is less than 3%.