Coupled model for contaminant diffusion, osmosis and consolidation in soil considering thermal effects

To explore the influences of temperature on pollutant transport, a coupled model for contaminant diffusion in soils, osmosis and consolidation considering the thermal effects is proposed to reflect the dynamic changes of physical properties of soils and transport properties in the process of pollutant transport and realize the coupling of diffusion, osmosis and consolidation. On the basis of verifying the validity of the model, the effects of thermal diffusion, thermo-osmosis, thermal consolidation and their combined effect on pollutant transport are analyzed. The simulated results show that the thermal diffusion and thermo-osmosis can accelerate contaminant transport, and with the increase of Soret coefficient and thermal permeability, the thermal diffusion and thermo-osmosis effects enhance. However, the thermal consolidation can slow down the pollutant transport rate, but with the increase of expansion coefficient of soils, the accumulation concentration of pollutant at the bottom of clay layer has little change. When the temperature difference is 40 K, the breakthrough time with considering the combined effects of thermal diffusion, thermo-osmosis and thermal consolidation can be shortened by 53.97 years compared with the results without considering the thermal effects.