Equivalent analytical models for assessment of landfill composite liners

In order to efficiently estimate the properties of landfill composite liners, equivalent analytical models based on time moment are proposed. The service performance of geomembrane layer (GMBL)/geosynthetic clay layer (GCL)/attenuation layer (AL) and GMBL/compacted clay layer (CCL)/AL are equivalent analyzed. The equivalent analysis and quantitative correlation of contaminants at the bottom of GMBL/GCL/AL and GMBL/CCL/AL are considered according to relative concentration (C_N), instantaneous flux (J_I) and accumulative flux (J_A). We showed that C_N is the most conservative equivalent index. The thickness equivalent relation of AL for different composite liners is consequently obtained using the pure diffusion equivalent model and the advection-diffusion equivalent model, respectively. It is found that the pure diffusion thickness equivalent relationship was a simplified linear correlation and time independent. The quadratic polynomial equivalent equations of AL thickness for different service time are obtained by group method of data handling approach (GMDH). The results show that GCL composite liner has better environmental protection performance than CCL composite liner. When the thickness of GMBL/CCL/AL composite liner is fixed, the corresponding equivalent thickness of AL in GMBL/GCL/AL composite liner decreased with the rise of leachate head and wrinkle length for the same value of C_N.