Research on the Critical Value of Sand Permeability Particle Size and Its Permeability Law after Mixing

Abstract

The permeability of sand is an important factor in determining the movement and occurrence of liquids and gases in sand. The current work studied the influence of soil particle size and gradation on permeability by testing the permeability of different sand samples that consist of defined sand particles in certain ratios. The results of a total of 640 sets of experiments were analyzed and compared with the corresponding theoretical calculations. We found that the sand can be divided into four groups based on particle size: high-permeability particles, medium-permeability particles, low-permeability particles and non-permeable particles; and the critical particle size of sand for permeability is 0.050 mm. Permeation will be lost when non-permeable particles account for >75% of the total in the mixture of high-permeability particles and non-permeable particles. Permeation will be very easily lost when medium- or low-permeability particles are mixed with non-permeable particles. The current findings are of importance for assessing the permeability of sand based on particle size.