Grading evolution and critical state in a discrete numerical model of Fontainebleau sand

Ciantia, Matteo Oryem; Arroyo, Marcos; O’Sullivan, Catherine; Gens, Antonio; Liu, Tingfa

doi:10.1680/jgeot.17.p.023

Cited by 91 publications

(37 citation statements)

References 58 publications

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“…The grain size distribution is also close to that of Fontainebleau sand [66]. More recently, Ciantia et al [17] refined this calibration, using new data to obtain better experimental agreement at very high pressures. The work presented here is not aimed to match laboratory experiments and, for coherence with previous work on response envelopes, the model parameters applied ( Table 1) are those of Ciantia et al [16].…”

Section: Dem Particle Crushing Modelmentioning

confidence: 63%

“…1). As explained in detail by Ciantia et al [17], this CSL is that relevant to normally consolidated states such as those considered here. The p 0 -constant stress path accelerates the crushing-induced evolution with respect to that observed along the isotropic path ( Fig.…”

Section: Initial Statesmentioning

confidence: 93%

“…Ciantia et al [15,16] concluded that a 14-ball crushed configuration can adequately represent macroscopic behaviour. The capability of this model to capture real test behaviour has been demonstrated by Ciantia et al [14,17].…”

Section: Dem Particle Crushing Modelmentioning

confidence: 96%

“…4b). At the critical state (CS), Ciantia et al [17] observed a practically unique relation between mean stress level and Z m , that is insensitive to grading. This is again noted here, where the end points ( Fig.…”

Section: Crushing Effect On Fabric Developmentmentioning

confidence: 99%

See 3 more Smart Citations

Micromechanical inspection of incremental behaviour of crushable soils

Ciantia

Arroyo²,

O’Sullivan

et al. 2019

Acta Geotech.

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In granular soils grain crushing reduces dilatancy and stress obliquity enhances crushability. These are well-supported specimen-scale experimental observations. In principle, those observations should reflect some peculiar micromechanism associated with crushing, but which is it? To answer that question the nature of crushing-induced particle-scale interactions is here investigated using an efficient DEM model of crushable soil. Microstructural measures such as the mechanical coordination number and fabric are examined while performing systematic stress probing on the triaxial plane. Numerical techniques such as parallel and the newly introduced sequential probing enable clear separation of the micromechanical mechanisms associated with crushing. Particle crushing is shown to reduce fabric anisotropy during incremental loading and to slow fabric change during continuous shearing. On the other hand, increased fabric anisotropy does take more particles closer to breakage. Shear-enhanced breakage appears then to be a natural consequence of shear-enhanced fabric anisotropy. The particle crushing model employed here makes crushing dependent only on particle and contact properties, without any pre-established influence of particle connectivity. That influence does not emerge, and it is shown how particle connectivity, per se, is not a good indicator of crushing likelihood.

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Section: Dem Particle Crushing Modelmentioning

confidence: 63%

Section: Initial Statesmentioning

confidence: 93%

Section: Dem Particle Crushing Modelmentioning

confidence: 96%

Section: Crushing Effect On Fabric Developmentmentioning

confidence: 99%

See 2 more Smart Citations

Micromechanical inspection of incremental behaviour of crushable soils

Ciantia

Arroyo²,

O’Sullivan

et al. 2019

Acta Geotech.

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“…The discrete-element method (DEM), first proposed by Cundall and Strack (1979), is a numerical approach widely used to study fundamental aspects of soil response (Calvetti et al, 2003;Huang et al, 2014b;Ciantia et al, 2016bCiantia et al, , 2018. Typically, small cubic or cylindrical samples are generated to obtain a 'representative elementary volume' (REV), which is later tested to explore different links between micromechanical features and the mesomechanical response of soil.…”

Section: Introductionmentioning

confidence: 99%

Numerical techniques for fast generation of large discrete-element models

Ciantia

Boschi

Shire

et al. 2018

Proceedings of the Institution of Civil Engineers - Engineering

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In recent years, civil engineers have started to use discrete-element modelling to simulate large-scale soil volumes thanks to technological improvements in both hardware and software. However, existing procedures to prepare ‘representative elementary volumes’ (REV) are unsatisfactory in terms of computational cost and sample homogeneity. In this work, a simple but efficient procedure to initialise large-scale discrete-element models is presented. Periodic cells are first generated with a sufficient number of particles (enough to consider the cell an REV) matching the desired particle-size distribution and equilibrated at the desired stress state, porosity and coordination number. When the cell is in equilibrium, it is replicated in space to fill the problem domain, and when the model is filled, only a small number of mechanical cycles is needed to equilibrate a large domain. The result is an equilibrated homogeneous sample at the desired initial state in a large volume.

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Relationships between gradation and deformation behavior of dense granular materials: Role of high‐order gradation characteristics

Liu

Deng

et al. 2021

Num Anal Meth Geomechanics

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This paper numerically investigates deformation behavior of coarse‐grained granular materials with emphasis on the effect of grain size distribution (GSD). Biaxial compression tests are simulated in two dimensions using distinct element method (DEM) on a set of samples composed of uncrushable spheres following a wide variety of GSDs. The results prove that high‐order characteristics of gradation, such as the shape of the GSD curve, significantly affect deformation behavior of widely‐graded materials. Two grading indices are proposed to consider the combined effects of the spread and the shape of the GSD curve, and they are highly correlated with the parameters of the materials’ internal fabric. Strong correlations are found between the proposed grading indices and deformation parameters, such as those of the normal compression line and the critical state line (CSL) in the e‐p space, and the deformation modulus. In contrast, using the more conventional coefficient of uniformity cannot reach effective gradation‐dependent relations for those deformation parameters due to the deficiency in characterizing high‐order features of gradation. This study suggests the need for incorporating high‐order characteristics of gradation into a refined measure of size polydispersity in order to establish gradation‐dependent relations of deformation parameters widely effective for polydisperse granular materials.

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Grading evolution and critical state in a discrete numerical model of Fontainebleau sand

Cited by 91 publications

References 58 publications

Micromechanical inspection of incremental behaviour of crushable soils

Micromechanical inspection of incremental behaviour of crushable soils

Numerical techniques for fast generation of large discrete-element models

Relationships between gradation and deformation behavior of dense granular materials: Role of high‐order gradation characteristics

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