Coupled model for one‐dimensional nonlinear consolidation and organic contaminant transport in a triple‐layer composite liner considering the nonisothermal distribution condition

Abstract

The transport characteristics of organic contaminants are significantly affected by nonlinear consolidation and thermal‐diffusion behaviors. However, there is currently a lack of associated theoretical research on this topic. This study develops a coupled model for one‐dimensional (1D) nonlinear consolidation and organic contaminant transport in GM/GCL/CCL (geomembrane [GM], geosynthetic clay liner [GCL], and compacted clay liner [CCL]) composite liner considering the nonisothermal distribution condition. In particular, the influences of temperature on the parameters are incorporated, and the corresponding finite difference solutions are obtained. Furthermore, the rationality of the proposed theoretical model is effectively verified by conducting comparative analysis under different circumstances. Following this, the transport behaviors are investigated based on the defined breakthrough time tb${t_b}$. Compared with the isothermal distribution state (temperature difference normalΔT0.33em=0.33em00.33emnormalK$\Delta T\ = \ 0\ {\rm{K}}$), the tb${t_b}$ at normalΔT$\Delta T$ equal to 10, 20, 30, and 40 K decreases by 25.4%, 41.3%, 52.2%, and 60.1%, respectively. The effect of thermal‐diffusion on the transport process is notable when the Soret coefficient ST${S_T}$ ranges between 0.01 and 0.050.33emK−1$0.05\ {{\rm{K}}^{ - 1}}$. Moreover, compared with the case of no consolidation (loading rate Qu=0.33em00.33emkPa/year${Q_u} = \ 0\ {\rm{kPa}}/{\rm{year}}$), the tb${t_b}$ at Qu${Q_u}$ equal to 50, 100, 150, and 200kPa/year$200{\rm{\ kPa}}/{\rm{year}}$ increases by 27.1%, 49.9%, 68.1%, and 83.9%, respectively. As the diffusion coefficient Dm,R${D_{m,R}}$ in GM changes from 0.1×10−13$0.1 \times {10^{ - 13}}$ to 1.0×10−130.33emm2/normals$1.0 \times {10^{ - 13}}\ {{\rm{m}}^2}/{\rm{s}}$, Dm,R${D_{m,R}}$ is observed to have a marked effect on the transport behavior.