Research on the Gas Migration Regularity of Municipal Solid Waste Landfill in the Solid-Liquid-Gas-Heat Interaction

With the establishment of large municipal solid waste landfills, the interaction of geological environment in landfill (seepage field, stress field and temperature field, etc.) has not to be ignored. The multi-field coupling problem of the municipal solid waste landfill is getting attention. But at present the study mainly concentrated on the solid-liquid-gas-heat coupling problem, the study of the waste gas of the municipal solid waste landfill is less. Gas diffusions, gas emissions, and gas collection are related to the secondary pollution problems of the municipal solid waste landfill. This paper established mathematical model which based on the solid-liquid-gas-heat interaction and researched the gas migration rule of the municipal solid waste landfills. The mainly work are as follows: (1) the definite conditions of dynamic model, (2) the solution of dynamic model, (3) results and analysis. The main conclusions are as follows: (1) Pore pressure along the gas flow direction is nonlinear distribution and shows decline trend. As time increases, the pore pressure of each horizontal section decreases. (2)The volumetric strain of the municipal solid waste landfill is nonlinear distribution along the gas flow direction and shows an increasing tendency. As time increases, volumetric strain of each horizontal section increases.(3)As the change of time, the pore pressure first increases, then decreases.(4) In the initial stage, as the change of time, gas output increases rapidly. When it achieves the maximum size, the production quantity of gas reduces and gradually tends to be a quantitative value.