Discrete particle translation gradient concept to expose strain localisation in sheared granular materials using 3D experimental kinematic measurements
Author | Ckrey A.M. |
Author | Alshibli K.A. |
Author | Al-Raoush R.I. |
Available date | 2020-02-05T08:53:07Z |
Publication Date | 2018 |
Publication Name | Geotechnique |
Resource | Scopus |
ISSN | 168505 |
Abstract | It is well known that the constitutive behaviour of granular materials is influenced by strain localisation into zones of intensive shearing, known as shear bands. The failure mode of specimens tested under axisymmetric triaxial compression is commonly manifested through single or multiple shear bands, or diffuse bifurcation (bulging). The ability to monitor and detect the evolution of strain localisation has been enhanced by measuring particle kinematics using discrete-element methods or three-dimensional imaging techniques such as X-ray computed tomography. However, conventional particle kinematic techniques cannot expose intricate localised shearing during the hardening, before the peak principal stress ratio. This paper presents the concept of particle translation gradient to expose strain localisation in granular materials using experimental measurements of particle translation in three dimensions. Individual silica sand particles were identified and tracked through multiple strains and particles' translations were calculated. Each particle's neighbouring particles were identified and translation fields for each of the neighbouring particles were calculated. The second-order norms between a particle translation vector and the neighbouring particles' translation vectors were averaged, resulting in a relative translation value for each particle. The translation gradient concept is effective in uncovering the onset of strain localisation within sheared granular materials. |
Sponsor | ACKNOWLEDGEMENTS This material is partially funded by the US National Science Foundation (NSF) under grant no. CMMI-1266230 and Office of Naval Research (ONR) grant no. N00014-11-1-0691. Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the NSF or ONR. The SMT images presented in this paper were collected using the X-Ray Operations and Research Beamline Station 13-BMD at Argonne Photon Source (APS), a U.S. Department of Energy (DOE) Office of Science user facility operated for the DOE Office of Science by Argonne National Laboratory under contract no. DE-AC02-06CH11357. The authors acknowledge the support of GeoSoilEnviroCARS (Sector 13), which is supported by the National Science Foundation � Earth Sciences (EAR-1128799), and the Department of Energy, Geosciences (DE-FG02-94ER14466). They also thank Dr Mark Rivers of APS for help in performing the SMT scans. |
Language | en |
Publisher | ICE Publishing |
Subject | Deformation Failure Sands Strain |
Type | Article |
Pagination | 162-170 |
Issue Number | 2 |
Volume Number | 68 |
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