Calculating the state parameter in crushable sands

TY - JOUR

T1 - Calculating the state parameter in crushable sands

AU - Ciantia, Matteo

AU - O'Sullivan, Catherine

PY - 2020/7/1

Y1 - 2020/7/1

N2 - 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.

AB - 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.

KW - Discrete-element modelling

KW - state parameter

KW - sands

KW - shear strength

KW - stress path

KW - static liquefaction

KW - Sands

KW - State parameter

KW - Shear strength

KW - Static liquefaction

KW - Discrete-element modeling

KW - Stress path

UR - https://www.scopus.com/pages/publications/85083917480

U2 - 10.1061/(ASCE)GM.1943-5622.0001707

DO - 10.1061/(ASCE)GM.1943-5622.0001707

M3 - Article

SN - 1532-3641

VL - 20

JO - International Journal of Geomechanics

JF - International Journal of Geomechanics

IS - 7

ER -