Macro- and micromechanical evaluation of cyclic simple shear test by discrete element method--颗粒学报PARTICUOLOGY

Asadzadeh, M., & Soroush, A. (2017). Macro- and micromechanical evaluation of cyclic simple shear test by discrete element method. Particuology, 31, 129-139. https://doi.org/10.1016/j.partic.2016.05.015

Macro- and micromechanical evaluation of cyclic simple shear test by discrete element method

Mozhgan Asadzadeh, Abbas Soroush ^*

Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran

10.1016/j.partic.2016.05.015

Volume 31, April 2017, Pages 129-139

Received 16 July 2015, Revised 11 April 2016, Accepted 3 May 2016, Available online 18 November 2016, Version of Record 9 March 2017.

E-mail: soroush@aut.ac.ir; abbas958@gmail.com

Highlights

• Stacked-ring simple shear test under monotonic and cyclic loading was modeled using 3D-DEM.

• Macro- and micromechanical properties of the specimens were investigated.

• Cyclic behavior, principal stress rotation, and fabric anisotropy inside specimens were discussed.

• The possible non-uniformities in shear and volumetric strain distributions were explored.

Abstract

Direct simple shear tests are considered to be simple laboratory tests that are capable of imposing a cyclic loading that is analogous to that induced by earthquakes. A realistic evaluation of the test results demands a profound micromechanical investigation of specimens. Three-dimensional discrete element method models of a stacked-ring simple shear test were constructed, in which monotonic and cyclic loadings were applied under constant-volume conditions, and good agreement between the monotonic and cyclic macromechanical behaviors was noted. Micromechanical properties of specimens that were subjected to a cyclic loading are discussed in terms of lateral and intermediate principal stress development, fabric anisotropy, and principal stress rotation. The stress and strain states inside the specimen were investigated and it was shown that despite the uniform stress distribution inside the specimen, the volumetric strain distributes non-uniformly during loading and the non-uniformity grows with cycling, which leads to localized zones of dilative and contractive behavior.

Graphical abstract

Keywords

Discrete element method; Direct shear test; Simple shear test; Cyclic loading

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