Journal article

Micromechanics of vortices in granular media: connection to shear bands and implications for continuum modelling of failure in geomaterials

Antoinette Tordesillas, Sebastian Pucilowski, David M Walker, John F Peters, Laura E Walizer

INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS | WILEY-BLACKWELL | Published : 2014

Abstract

SUMMARY: Recent analysis of data from triaxial tests on sand and discrete element simulations indicate the final pattern of failure is encoded in grain motions during the nascent stages of loading. We study vortices that are evident from grain displacements at the start of loading and bear a direct mathematical connection to boundary conditions, uniform continuum strain and shear bands. Motions of three grains in mutual contact, that is, 3-cycles, manifest vortices. In the initial stages of loading, 3-cycles initiate a rotation around a region Ω* where the shear band ultimately develops. This bias sets a course in 3-cycle evolution, determining where they will more likely collapse. A multisc..

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Grants

Awarded by Australian Research Council


Awarded by US Army Research Office Single Investigator Award Scheme


Funding Acknowledgements

We thank Dr Qun Lin for useful discussions. We are also grateful to Felix Darve, Luc Sibille, Ali Daouadji and Francois Nicot for kindly permitting use of their diffuse failure data and Mark Hopkins for the triaxial polyellipsoid data. This study was supported by the Australian Research Council (Discovery Projects DP120104759), the Melbourne Energy Institute, US Army Research Office Single Investigator Award Scheme W911NF-11-1-0175 and the Gilbert Riggs PhD Scholarship (SP).