Shear strength in preexisting landslides

Timothy D. Stark, Manzoor Hussain

Research output: Contribution to journalArticlepeer-review


Drained residual shear strength is used for the analysis of slopes containing preexisting shear surfaces. Some recent research suggests that preexisting shear surfaces in prior landslides can gain strength with time. Torsional ring and direct shear tests performed during this study show that the recovered shear strength measured in the laboratory is only noticeably greater than the drained residual strength at effective normal stress of 100 kPa or less. The test results also show that the recovered strength even at effective normal stresses of 100 kPa or less is lost after a small shear displacement, i.e., slope movement. An effective normal stress of 100 kPa corresponds to a shallow depth so the observed strength gain has little, if any, impact on the analysis of deep landslides. This paper describes the laboratory strength recovery testing and the results for soils with different plasticities at various rest periods and effective normal stresses.

Original languageEnglish (US)
Article number010007QGT
Pages (from-to)957-962
Number of pages6
JournalJournal of Geotechnical and Geoenvironmental Engineering
Issue number7
StatePublished - Jul 1 2010


  • Landslides
  • Overconsolidated clays
  • Ring shear test
  • Shear strength
  • Slope stability
  • Soil mechanics
  • Strength recovery

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Environmental Science(all)


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