The Influence of Hydrothermal Effect on Migration of Contaminants in Porous Media

Abstract

This paper extends a one-dimensional model of adsorbed contaminants in saturated porous media to establish a three-dimensional case suitable for unsaturated porous media. The effects of hydrothermal influences on the distributions of temperature and moisture, evolution of the bulk strain and migration of nuclides are simulated and analysed, and the coupled thermo-hydro-mechanical governing equations determined by the author are presented. The results show that the saturation in the buffer layer gradually rises to 0.96 from the initial value of 0.5 after approximately 450 years, and increases slowly in the initial stage of the simulation. The nuclide concentration in the solidified body first increases and then decreases, reaching a maximum of 173.05 mol/m3 in approximately 110 years. Moreover, most of the radionuclides are released by buffer layer adsorption and the adsorbed concentration is almost 100 times the solute concentration. In addition, the calculation also shows that the nuclides penetrate the buffer and reach the surrounding rock approximately 400 years later.