Efficient determination of aqueous-phase gas diffusion coefficients and tortuosity in soil

Diffusion of dissolved aqueous-phase gas in porous media is increasingly relevant to existing and emerging geotechnical engineering applications. There is currently no established method to determine the effective aqueous-phase gas diffusion coefficient and associated tortuosity factor through soil. In this study, a pressure-decay method was applied to determine tortuosity factors for aqueous-phase gas diffusion in silt, sand and gravel using experimental equipment readily available in many geotechnical engineering laboratories. Inverse numerical analyses were applied to assess the effective tortuosity factor from pressure-decay data, which provided a consistent and efficient assessment of tortuosity associated with aqueous-phase gas diffusion for each soil type.