关键词: 解析解, 非等温条件, 压实黏土衬垫, 污染物运移

Abstract: Analytical solutions of contaminant transport in a compacted clay liner (CCL) under non-isothermal condition are derived through the generalized integral transform technique. The proposed analytical solutions account for the coupling effects of molecular diffusion, advection, sorption and thermal diffusion. In addition, the variations of CCL permeability coefficient, CCL distribution coefficient and CCL effective diffusion coefficient with temperature are also considered in the analytical solutions. The proposed analytical solutions are successfully validated against the experimental results of thermal diffusion tests, the analytical solutions available in previous studies and COMSOL numerical results, respectively. Then the effects of non-isothermal condition, permeability coefficient, effective diffusion coefficient and distribution coefficient of CCL on the transport of benzene in CCL system were studied through the verified analytical solutions. The results indicate that the non-isothermal condition and the variations of permeability coefficient, effective diffusion coefficient and distribution coefficient of CCL with temperature all have significant effects on benzene transport in the CCL system. The mass flux and breakthrough time of contaminant can be substantially underestimated without considering the effect of non-isothermal condition. The previous analytical solutions that neglect the variations of CCL permeability coefficient and CCL effective diffusion coefficient with temperature can substantially underestimate the benzene outflow rate, whereas neglecting the variation of CCL distribution coefficient with temperature can substantially overestimate the cost time of benzene to penetrate the liner system and reach steady-state. The proposed analytical solutions that consider the effects of thermal diffusion as well as the variations of CCL permeability coefficient, CCL distribution coefficient and CCL effective diffusion coefficient with temperature are more suitable for the engineering practice. It can be adopted to improve the design scheme and the service performance evaluation of CCL system.

Key words: analytical solution, non-isothermal condition, compacted clay liner, contaminant transport