中文摘要：

为了研究垃圾填埋场内部生物降解产生的气体（以甲烷为主）和氧气等在非饱和覆盖层中的运移规律，建立了气体在成层非饱和覆盖层中的一维扩散模型．该模型考虑了覆盖层含水量瞬态变化和气体扩散的耦合作用．采用有限元多物理场耦合分析软件COMSOL Multiphysics4.3进行求解．其计算结果与前人实验结果能符合得很好．研究结果表明，对典型垃圾填埋场中厚度为1m的非饱和黏土覆盖层，含水量变化对覆盖层中气体污染物的扩散运移有显著影响．与含水量稳态变化情况相比，20d到100d的运移时问内同一覆盖层深度处耦合含水量作用下，气体相对浓度可以相差接近8倍．含水量是气体在非饱和覆盖层中不稳定运移的重要影响因素．

英文摘要：

A one-dimensional diffusion model of gas is developed to investigate landfill gas transport in unsaturated layered cover systems. Coupled processes of gas diffusion in the unsaturated cover and transient water transport in the media were considered. The mathematical model was solved by using the finite element analysis software COMSOL Multiphysics 4.3. The results obtained by the proposed model agree well with those obtained by the experimental meth-ods. It is shown that the variation of water content has great influence on landfill gas transport in a 1-meter-thickness unsaturated landfill cover soil. For the 1-meter-thcikness unsaturated cover soil, the relative gas concentrations for the case assuming coupled transport was approximately 8 times smaller than those assuming steady transport at the time range of 20 d to 100 d. It is indicated that the water content is of great importance when predicting the unsteady gas migration in unsaturated landfill cover systems.