Modelling the Deformation of a MSW Landfill Based on Tests

Abstract

In Hungary, a significant proportion of solid waste is get into landfills. In the future, we will have to find more modern methods for a waste treatment, but these landfills will work for a long time. It is necessary to prepare for recultivation or possible utilization of the area of these landfills. To solve these tasks, it has been having to know the physical, biological and chemical characteristics on the one hand, and we have to search for law of material and possibility for modelling to estimate and forecast the probable subsidence of the surface on the other hand. To solve the task, we had recourse to modelling which is one of the general methods of engineering. We chose the soil mechanical model from rheological, biodegradational, empirical, etc. ones. The examined municipal landfill is the Regional Waste Management Centre in Pusztazámor, which is one of the biggest landfills in Hungary. We took out 22 samples from two boring holes, and created average samples. The samples were put in categories according to degradation phase and the shear strength parameters were determined in the Technical University of Budapest. These data were used for our calculations of the settlement of the landfill hill. A bigger size oedometer was developed for the experiment. Considering the results of the in situ subsidence measuring, the calculation model was corrected and validated. It was used Plaxis 2D FEM program for modelling. Models MC, HS and SSC were used, and then we validated and controlled it. It has been found that model SSC describes reality with the accuracy expectable, when we built up the model layer by layer according to the degradation phase in time. The settlement of a municipal landfill were estimated applying the soil mechanical model.