Effects of the particle shape and size of sands on the hydraulic conductivity

Abstract

This study aims to investigate the effects of some physical properties of sands (e.g., size and shape) on the hydraulic conductivity (k). The paper presents the results of an extensive series of experimental investigations performed using sands with different sizes and particle shapes. Three different particle size ranges (0.60-1.18 mm, 1.18-2.00 mm, and 0.075-2.00 mm) of sands (i. Crushed Stone Sand, CSS; ii. Trakya Sand, TS; iii. Narli Sand, NS; iv. Fly Ash Pellets, FAP; v. Leighton Buzzard Sand, LBS) having distinct shapes, including roundness, R, and sphericity, S (R-i=0.15, S-i=0.55; R-ii=0.43, S-ii=0.67; S-iii=0.79; R-iv=0.65, S-iv=0.89; R-v=0.78 S-v=0.65) were tested in a constant-head permeability testing apparatus at a relative density (Dr) of about 35% and constant room temperature (20 degrees C). The experimental results showed that the sands having different shapes (R, S) with the same size and gradation characteristics (c(c), c(u), D-10, D-30, D-50, D-60) result in different k values. The scanning electron microscope (SEM) images indicate the physical differences/similarities among the sands used during this investigation. A comparative study of the tests results and the estimated hydraulic conductivity values using empirical equations previously developed for the hydraulic conductivity prediction of soils by certain researchers are presented.