Knowledge of the unit weight of Municipal Solid-Waste (MSW) is required for many engineering analyses. However, unit weight continues to be a significant source of uncertainty in these analyses due to a variety of factors, including the heterogeneous nature of solid waste, a paucity of data, and the lack of systematic analysis of the available data. Analysis of available in-situ and laboratory data on the unit weight of MSW, described herein, indicates both the existence of a “characteristic unit weight profile” for MSW and the need for site-specific unit weight data to develop an accurate unit weight profile for a particular landfill. A hyperbolic model is shown to capture the influence of compaction effort and overburden stress on MSW unit weight. Calibrated against laboratory and field data, the hyperbolic model provides a rational basis for developing landfill-specific MSW unit weight profiles for design.
