Limit equilibrium method based on an approximate lower bound method with a variable factor of safety that can consider residual strength

Yung Ming Cheng, D. Z. Li, L. Li, Y. J. Sun, R. Baker, Y. Yang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

20 Citations (Scopus)


In this paper, the factor of safety for a prescribed slip surface will be determined from an equivalent lower bound method (extremum principle), which can satisfy all equilibrium conditions without an interslice force function. This approach will give an overall factor of safety close to that from the classical methods for normal problems, while the thrust line, the local factor of safety for individual slice/block and the progressive yielding phenomenon can be estimated, which will be useful for some special cases. The force and moment equilibrium of every slice will be satisfied, while the location of the thrust line will always be acceptable in the present formulation. To solve the difficult optimisation problem, an innovative coupled particle swarm/harmony search algorithm is proposed in this paper, and a practical engineering problem for which the factor of safety is close to 1.0 is used to illustrate the consideration of the residual strength in the limit equilibrium slope stability analysis.
Original languageEnglish
Pages (from-to)623-637
Number of pages15
JournalComputers and Geotechnics
Issue number5
Publication statusPublished - 1 Jul 2011


  • Extremum principle
  • Factor of safety
  • Global minimum
  • Harmony search
  • Local minimum
  • Particle swarm
  • Progressive yielding
  • Slope stability analysis

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Computer Science Applications

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