Aiming at the problem of one-dimensional transport of heavy metal contaminants (HMCs) in a triple-layer composite liner composed of geomembrane (GM)

geosynthetic clay liner (GCL) and compacted clay liner (CCL) under the consideration of temperature change

the governing equations for thermal conduction and HMCs transport are developed based on the relevant assumptions

and a corresponding theoretical model is established. The theoretical model constructed in this study is solved numerically by the finite difference. Subsequently

a comparative analysis with the experimental measurements

the analytical solution calculations and other numerical solution calculations is performed to validly verify the reasonableness of this model. Finally

the effects of different factors on the transport laws are analyzed and discussed using Cd as an example. The results show that an increase in the upper temperature increases the transport flux and bottom concentration of Cd in the composite liner

but decreases its upper concentration. The thermal diffusion effect on the transport behaviors becomes significant with an increasing in Soret coefficient ST

and the defined breakthrough times tb are 37.9

37.2

36.4

31.2 and 26.5 a for of 0.001

0.005

0.01

0.05 and 0.1 K in this order. The increase in the maximum adsorption capacities of GCL and CCL leads to the approximately linear growth in tb

and under a certain leachate head

the tb almost increases linearly with the increase of GCL thickness and CCL thickness. Furthermore

as increases from 0.5 m to 1.0 m

the reduces by an average of 8.33 a. In engineering practice

the adsorption performance and thickness of both GCL and CCL can be combined to design a composite liner

where the influence of temperature variation on barrier effectiveness should be incorporated.