Calculating the State Parameter in Crushable Sands

Abstract

The state parameter (y) 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 (# $) and peak dilatancy and y is central to many constitutive models used to predict granular soil behaviour. These correlations do not explicitly consider particle crushing. Crushing induced evolution of the particle size distribution influences the CSL position and recent research supports used of a critical state plane (CSP) to account for changes in grading. This contribution evaluates the whether the CSP can be used to calculate y and thus enable prediction of the peak angle of # $ 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 y is calculated by considering the CSL of the original uncrushed material there can be in a significant error in predicting the material response. Where the CSP is used there is a significant improvement in our ability to predict behaviour 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 liquefaction potential of potentially crushable soils. The contribution also highlights the stress-path dependency of the relationship between # $ and y whichever approach is used to determine y.

Grain roughness effect on the critical state line of crushable sands

“…Particle crushing changes the position of the CSL in the compression plane (Bandini and Coop, 2011;Sadrekarimi and Olson 2014). These experimental results were corroborated and extended in DEM simulations by (Ciantia et al 2019, Ciantia andO'Sullivan 2020) using a crushable DEM model calibrated to represent Fontainebleau sand.…”

Constitutive Modeling for Two Sands under High Pressure

“…affected by particle breakage (Ueng and Chen 2000;Coop et al 2004;Russell and Khalili 2004;Zhang and Baudet 2013;Hyodo et al 2016;Yu 2017b;Mao et al 2019;Ovalle and Hicher 2019;Ganju et al 2020), which reduces the dilatancy and peak strength, and enhances the hardening and contraction behaviors of sands (Indraratna and Salim 2002;Hasanlourad et al 2008;Sadrekarimi and Olson 2011a;Liu et al 2016;Yu 2017b;Ciantia and O'Sullivan 2020;Wang et al 2020;Zhang and Luo 2020).…”

Testing and Modeling on Particle Breakage for Granular Soils

“…The macroscopic behaviors (such as the strain softening and volumetric dilation behaviors of the rough interface and the strain hardening and volumetric contraction behaviors of the smooth interface) strongly correlated with the microstructural anisotropy evolution. Ciantia and O'Sullivan (2020) proposed a method to modify the state parameter for crushable soils in the critical state plane that was formed by introducing the grading state index into the compression plane. The employment of this revised state parameter could overcome the limitation that was found during the estimation of the liquefaction susceptibility of crushable soils based on the common state parameter in the compression plane.…”

“…It was found that a nonlinear CSL in the stress plane correlated with the relative breakage index. A CSL in the compression plane was extended to a critical state plane (CSP) by incorporating the effect of particle breakage, which is similar to that in those studies (Liu and Zou 2013;Ciantia and O'Sullivan 2020). The evolution of particle breakage was expressed as a hyperbolic function of axial strain.…”