Calculating the state parameter in crushable sands

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

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)
157 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

ASJC Scopus subject areas

  • Soil Science


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