Assessment of column to particle diameter ratio on the hydraulic conductivity of porous media: Wall effect in Darcy Regime

Abstract

ABSTRACT The study of flow through porous media concerning the movement of dissolved contaminants and groundwater investigations is of immense significance. The present study investigates the influence of the wall effect on the hydraulic conductivity (K) of borehole soil samples. Various parameters namely shape factor, porosity, and particle size have been taken into consideration to examine the relative resistance offered by the permeameter wall. For this, the dependence of confined and unconfined K, i.e. (K c/K u), was assessed with different values of the column to particle diameter ratio (dc/dp). The results of experimental work indicate that the K c/K u attains a value greater than unity for dc/dp value up to 140, and equal to unity for dc/dp value beyond 140. This postulates that the wall effect is dominant only up to the dc/dp value of 140, whereas any further increase in this value indicates an insignificant wall effect. The wall effect influence on the K has been validated by studying the variation of pressure drop coefficients with the different values of the dc/dp ratio. The study proposes a model for accurate K estimation by considering the precise wall effect influence.