Municipal Solid Waste Slope Stability Modeling: A Probabilistic Approach

Abstract

The geotechnical properties (e.g., density, friction angle, and cohesion) of waste material in landfills and dumpsites vary significantly, depending on the waste composition and compaction practices. This variability results in a major source of uncertainty in slope stability analysis for municipal solid waste (MSW) disposal sites. This study presents a novel probabilistic approach for slope stability analysis by backcalculation, assigning probability distributions to waste material properties. Using backanalysis of historical, well-documented failed waste slopes, probability distributions for the density, friction angle, and cohesion of MSW are assigned based on the disposal method (landfill or dumpsite) and waste material composition (fibrous or food waste materials). MSW with (1) major food waste contents has lower shear strength (friction angle = 22.2° and cohesion = 19.2 kPa) in comparison with MSW with major fibrous waste contents (friction angle = 34° and cohesion = 14 kPa) and (2) compaction practices in landfills compared to dumpsites result in 20% higher shear-strength properties for the waste material. The application of this new approach and its advantages is demonstrated/validated using four case studies (Rumpke, Durban, Istanbul, and Sarajevo).