Diffusion Anisotropy Through Soft Clay

Abstract

This study pertains to the quantification of contaminant transport parameters of heavy metal zinc diffusing through saturated soft Bangkok undisturbed clay in the two principal flow directions (vertical direction) perpendicular to and (horizontal direction) parallel to natural bedding marine clay. By using the column tests, the effective diffusion and distribution, De and Kd, coefficients were determined by curve fitting to the test data using the POLLUTE software. The results showed that horizontal diffusion is relatively faster (diffusion coefficient higher and distribution coefficients lower) than vertical due to microstratifications and loose bond between adjacent layers. Thus, these heterogeneities caused high anisotropy not only in hydraulic conductivity but also in diffusion coefficient and distribution coefficients.