Coupling model for consolidation and contaminant transport in compactedclay liners under non-isothermal condition

Considering that the heat production inside the contaminated site will make the compacted clay liner (CCL) be in a non-isothermal distribution state, a consolidation-contaminant transport coupling model for the CCL subjected to non-isothermal condition is established, and the finite difference method is used to solve the coupling model. The correctness of the established coupling model is verified by comparing the calculated results of the coupling model with the results of the thermal diffusion tests and those of the existing theoretical models, respectively. Based on the established coupling model, the effects of temperature gradient, loading rate and Freundlich adsorption coefficient on the transport process of contaminant are analyzed through an example. The results show that the concentration and bottom flux of contaminants increase with the increase of the absolute value of temperature gradient. Under a certain temperature gradient, the bottom flux of contaminant can be more than twice the bottom flux without considering the temperature gradient. On the one hand, the increase of loading rate will slow down the transport rate of contaminant. On the other hand, it will increase the concentration of contaminant when the transport process reaches a steady state. The increase of Freundlich adsorption coefficient will slow down the transport process of contaminant. The time required for the transport process to reach the steady state can be prolonged by three times or more when the adsorption effect is considered.