Abstract:In this study, the flow of gas and leachate to vertical wells in landfills was investigated. Neglecting the flow of landfill gas and leachate in the vertical direction, and based on the degradation of organic matter, gas-leachate constitutive relationship, and gas-leachate continuous conditions, the flow equation under the condition of a plane axisymmetric gas-leachate coupling effect was established with gas pumping and leachate recirculation. The analytical solution in the unsteady state of the simplified equation is presented under conditions of passive and active extraction wells. The results show that the pore water pressure and gas pressure increased with the distance from the extraction well. The pore water pressure dispersed as time went on, and the gas pressure increased to its peak value initially, and then dispersed. The gas pressure that considered the gas-leachate coupling effect was relatively higher. The coupling effect on gas pressure was reduced with the increase of gaseous permeability, and become more significant with the increase of liquid permeability.