Calculating the state parameter in crushable sands

Matteo Ciantia (Lead / Corresponding author), Catherine O'Sullivan

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)
110 Downloads (Pure)


The state parameter (ψ) measures the distance from the current state to the critical state line (CSL) in the compression plane. The existence of a correlation between both the peak angle of shearing resistance (φ p ′) and peak dilatancy and ψ is central to many constitutive models used to predict granular soil behavior. These correlations do not explicitly consider particle crushing. Crushing-induced evolution of the particle size distribution influences the CSL position, and recent research supports the use of a critical state plane (CSP) to account for changes in grading. This contribution evaluates whether the CSP can be used to calculate ψ and thus enable the prediction of the peak angle of φ p ′ and peak dilatancy where crushing takes place. The data considered were generated from a validated DEM model of Fontainebleau sand that considers particle crushing. It is shown that where ψ is calculated by considering the CSL of the original uncrushed material, there can be a significant error in predicting the material response. However, where the CSP is used, there is a significant improvement in our ability to predict behavior irrespective of whether the CSP is accurately determined using a large number of tests or approximated using crushing yield envelopes. It is shown that the state parameter calculated using the previously available definition can give a false sense of security when assessing the liquefaction potential of potentially crushable soils. This contribution also highlights the stress-path dependency of the relationship between φ p ′ and ψ whichever approach is used to determine ψ.

Original languageEnglish
JournalInternational Journal of Geomechanics
Issue number7
Early online date22 Apr 2020
Publication statusPublished - 1 Jul 2020


  • Discrete-element modelling
  • state parameter
  • sands
  • shear strength
  • stress path
  • static liquefaction
  • Sands
  • State parameter
  • Shear strength
  • Static liquefaction
  • Discrete-element modeling
  • Stress path


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