Abstract: To accelerate the stabilization of degradation in landfills, leachate recirculation is often used in practical engineering, and recirculation using a vertical well is one of the more effective ways. With the injection of liquid, the temperature in the waste will change due to convection. In this study, the variation of waste temperature during the field test was first simulated based on the water injection test in the Wuxi landfill. A seepage flow model considering the variations in permeability and porosity with depth as well as a thermal convection-thermal conduction model considering the effect of seepage flow were then established, which were used to calculate the seepage and thermal convection-conduction processes of the landfill in numerical simulation. Comparison of theoretical and numerical results shows that the established models can well simulate the variations of leachate level and waste temperature during the water injection. The results are as follows: The leachate level is relatively lagged in the position more than 6 m away from the injection well, at least 0.15 days behind, and the farther the distance, the longer the lag time. Below the leachate level, the waste temperature around the injection well is lower than the initial temperature. However, the waste temperature 3.6 m away from the injection well in the radius direction is not all below the initial temperature. The temperature will be higher than the initial temperature within 2 m above the new and old waste junction, where the temperature difference can reach 3 ℃. The waste degraded time significantly affects temperature distribution under single well water injection.

Key words: landfill, waste, water injection, temperature, simulation