Abstract：To study the influence of refuse pore gas pressure on the landfill settlement，a mathematical model was developed，which simplified the landfill as a one-dimensional unsteady gas seepage field. The model incorporated Gibson and Lo model，U.S. EPA Landgem model，Darcy¢s law，ideal gas law，principle of effective stress and theory of dynamics of fluids in porous media. According to the model，the landfill settlement was calculated by the active stage and closed stage，respectively. During the active stage，the landfill continually received refuse，which led to the increase of loads. During the closed stage，the loads kept constant. The result of the finite difference solution represented that the pore gas pressure in the landfill was influenced by the depth，time and permeability. The pore gas pressure increased with the depth and time in the active stage，and dispersed gradually in the closed stage. The landfill with a high permeability has a high rate of pore gas pressure dispersing. The decrease of settlement rate，caused by the increase of gas pore pressure，will decrease the capacity of the landfill. The gas pore pressure should be considered to calculate the settlement and to evaluate the stability of landfills.
