Abstract
In this study, ion seepage tests were conducted by using fine-grained soil with permeability coefficients (k) ranging from 1.0*10-6 to 1.0*10-10 m/s. In the tests, density flow and molecular diffusion were induced by giving the concentration gradient but not the hydraulic gradient to investigate the parameters affecting the movement of fine-grained soil in an inverse problem approach. Numerical analyses were also performed to evaluate the barrier performance of the fine-grained soil. The study revealed that (1) the permeability coefficient k of a bentonite-soil mixture and the effective diffusion coefficient Dd* are dependent on effective porosity ne, (2) it may be possible to estimate the effective porosity ne of a bentonite-soil mixture and the effective diffusion coefficient Dd* with relative ease from the consistency limit and (3) there is a considerable diff erence in barrier performance betwee n a 5.0-meter-thick soil layer (barrier layer) with a pe rmeability coefficient k of 1.0*10-7 m/s and a 0.5-meter-thick barrier wall with a permeability coefficient k of 1.0*10-8 m/s.
