Modeling of Permeability in Stratified Sands Using a Wave-Propagation Method

Abstract

Layered soils are often encountered in nature; hence, it is important to determine the coefficient of permeability in them, due to its effect on ground contamination and the recharging of water basins. While porosity–permeability relationships in pure clays and sands are well established in the literature, the permeability of natural sedimentary basins remains highly uncertain. Theoretical equations based on Darcy’s law are often used to determine the coefficient of permeability in layered soil. However, the results obtained from these equations are often found to be different from the measured values of permeability using field testing. Moreover, there is a very limited body of literature available on the validity of Darcy’s law in layered soils. With this in view, experiments were carried out in the laboratory to determine the coefficient of permeability in stratified soils (single, double, and triple-layered sands). The measured values of permeability were then correlated to the characteristic frequencies of elastic shear and/or compression waves obtained from bender/extender tests. Using Biot’s theory of wave propagation and Darcy’s law, mathematical equations were further developed to predict the permeability of layered soils. Based on the results obtained from the present study and the data available in the literature, it was demonstrated that the permeability of layered soils can be predicted reasonably well from these equations.