Elastic viscoplastic modelling of the time-dependent stress-strain behaviour of soils

Jianhua Yin, James Graham

Research output: Journal article publicationJournal articleAcademic researchpeer-review

185 Citations (Scopus)


This paper presents a new framework for elastic viscoplastic (EVP) constitutive modelling. In developing the model, a general one-dimensional elastic viscoplastic (1D EVP) relationship is first derived for isotropic stressing conditions using an 'equivalent-time' concept. This 1D EVP model is then generalized into a three-dimensional EVP model based on Modified Cam-Clay and viscoplasticity. Fitting functions are proposed for fitting data when model parameters are being determined. Using these functions, a specific EVP model is developed which describes the time-dependent stress-strain behaviour of soils under triaxial stress states. This model has been calibrated using data from a densely compacted sand-bentonite mixture. The calibrated model is used to compute time-dependent (or strain rate dependent) stress-strain curves from a multistage shear creep test and a step-changed, constant strain rate undrained triaxial compression test. Predictions from the EVP model are in general agreement with measured values. It is demonstrated that the model can simulate accelerating creep when deviator stresses are close to the shear strength envelope in a q creep test. It can also model the behaviour in unloading-reloading and relaxation. Limitations and possible improvements are also indicated.
Original languageEnglish
Pages (from-to)736-745
Number of pages10
JournalCanadian Geotechnical Journal
Issue number4
Publication statusPublished - 1 Jan 1999


  • Elastic
  • Equivalent time
  • Stress-strain
  • Time dependent
  • Triaxial
  • Viscoplastic

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology


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