Assessment of Long-Term Settlement Prediction Models for Municipal Solid Wastes Disposed in an Experimental Landfill

Settlement evaluation in sanitary landfills is a complex process, due to the waste heterogeneity, time-varying properties and influencing factors and mechanisms, such as mechanical compression due to the load application and creep, and physical-chemical and biological processes caused by the wastes decomposition. Many empirical models of analysis and long-term settlement prediction are reported in the literature, which require the application to real case studies in order to be validated. In this paper, four models of long-term settlement prediction (Rheological, Hyperbolic, Composite and Meruelo models) reported in the literature were applied to assess the mechanical behavior of an experimental landfill, composed of 6 different cells of municipal solid waste. Concerning the long-term settlement prediction, the results enabled a critical evaluation of the models, pointing out some advantages and limitations. During the monitoring period of 3 years, significant vertical strains were observed (of up to 22%) in relation to the initial height of the experimental landfill, which can be considered high and is due to fresh wastes with high organic content disposed. The results also suggest that the operational procedures influenced the settlements in the experimental landfill. The long-term settlement prediction indicated a final strain range from 22% to 42%, with respect to initial waste height and the composite model presented better comparisons between field measurements and predictions.