Abstract:

Based on the theory of fluid-solid coupling and dynamics of fluids in porous media, and incorporated with the Landgem model, Darcy’s law, state equation of gas, principle of effective stress, a seepage-stress fields coupling model of landfill gas transport has been established. Solutions to the coupled model are accomplished by finite element discretization. The numerical visualization simulation on the distribution law of gas pressure has been presented under coupling effect. The quantitative assessment to the effect of deformation media parameter and landfill degradation coefficient on landfill gas production has been analyzed. The results show that the gas pressure and gas yield in coupling action are less than uncoupling action, of which the reason is that the gas movement is blocked by changing of pore structures when pumping. And the production of landfill gas increase by the augmentation of permeability and degradation coefficient. Therefore, the effects of coupling cannot be ignored. The theoretical evidence is provided for forecasting migration and diffusion of landfill gas and preventing secondary-pollution. Moreover, it has important theoretical significance and practical use value for protecting ecological environment and resources utilization of landfill.

Key words: landfill gas, coupling model, seepage field, stress field, numerical simulation