Shear strength of municipal solid waste

Jonathan D. Bray, Dimitrios Zekkos, Edward Kavazanjian, George A. Athanasopoulos, Michael F. Riemer

Research output: Contribution to journalArticlepeer-review

145 Scopus citations


A comprehensive large-scale laboratory testing program using direct shear (DS), triaxial (TX), and simple shear tests was performed on municipal solid waste (MSW) retrieved from a landfill in the San Francisco Bay area to develop insights about and a framework for interpretation of the shear strength of MSW. Stability analyses of MSW landfills require characterization of the shear strength of MSW. Although MSW is variable and a difficult material to test, its shear strength can be evaluated rationally to develop reasonable estimates. The effects of waste composition, fibrous particle orientation, confining stress, rate of loading, stress path, stress-strain compatibility, and unit weight on the shear strength of MSW were evaluated in the testing program described herein. The results of this testing program indicate that the DS test is appropriate to evaluate the shear strength of MSW along its weakest orientation (i.e., on a plane parallel to the preferred orientation of the larger fibrous particles within MSW). These laboratory results and the results of more than 100 large-scale laboratory tests from other studies indicate that the DS static shear strength of MSW is best characterized by a cohesion of 15kPa and a friction angle of 36° at normal stress of 1atm with the friction angle decreasing by 5° for every log cycle increase in normal stress. Other shearing modes that engage the fibrous materials within MSW (e.g., TX) produce higher friction angles. The dynamic shear strength of MSW can be estimated conservatively to be 20% greater than its static strength. These recommendations are based on tests of MSW with a moisture content below its field capacity; therefore, cyclic degradation due to pore pressure generation has not been considered in its development.

Original languageEnglish (US)
Pages (from-to)709-722
Number of pages14
JournalJournal of Geotechnical and Geoenvironmental Engineering
Issue number6
StatePublished - 2009


  • Dynamic properties
  • Laboratory tests
  • Landfills
  • Municipal wastes
  • Shear strength
  • Solid wastes
  • Stress strain relations

ASJC Scopus subject areas

  • General Environmental Science
  • Geotechnical Engineering and Engineering Geology


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