Fabric Evolution in Granular Materials Under Strain Probing
The fabric of granular materials, as the underlying internal contact network through which the interparticle forces transmit the stress, plays a key role in describing their elasticity, critical state, and dilatancy, to name a few. Just as response envelopes have been developed by Gudehus back in 1979 to get an overall picture of constitutive models and the nature of constitutive equations, herein, the evolution of contact fabric in granular materials when subjected to strain probes is explored through series of Discrete Element Method (DEM) simulations. As the first study of its kind, and also due to the richness of the observed responses, the scope of the study has been limited to isotropic configurations. The contribution of contact loss, gain, and reorientation mechanisms to the changes in the associated second order fabric tensor has been investigated as the proportion of vertical to horizontal strain changed during a strain probing procedure. Intriguingly, the evolution of fabric with strain probes shows a strong asymmetry in compression and extension, signalling an incrementally nonlinear relation between fabric and strain increments, despite the incrementally linear elastic stress-strain response. Such results suggest that the origins of the incrementally nonlinear stress-strain responses often observed in later stages of deviatoric loading of granular materials can be potentially traced back to characteristics of fabric evolution.
Research funding jointly provided by the Natural Sciences and Engineering Research Council of Canada and Foundation Computer Modelling Group (now Energi Solutions Ltd.) is gratefully acknowledged. This work was initiated during a short research visit at the University of Twente, the Netherlands, by the first author. Sincere gratitude is due to the University of Twente for providing an enriching and stimulating environment for this work, which has subsequently flourished into this manuscript.
- 5.Calvetti, F., Viggiani, G., Tamagnini, C.: A numerical investigation of the incremental behavior of granular soils. Riv. Ital. Geotec. 37(3), 11–29 (2003)Google Scholar
- 7.Darve, F.: The expression of rheological laws in incremental form and the main classes of constitutive equations. In: Geomaterials: Constitutive Equations and Modelling, pp. 123–148 (1990)Google Scholar
- 11.Gudehus, G.: A comparison of some constitutive laws for soils under radially symmetric loading and unloading. Can. Geotech. J. 20, 502–516 (1979)Google Scholar
- 27.Radjai, F., Troadec, H., Roux, S.: Key features of granular plasticity. In Granular Materials: Fundamentals and Applications, pp. 157–184. Royal Society of Chemistry London, London (2004)Google Scholar
- 29.Rothenburg, L., Selvadurai, A.P.S.: A micromechanical definition of the Cauchy stress tensor for particulate media. In: Mechanics of Structured Media, pp. 469–486 (1981)Google Scholar
- 31.Satake, M.: Constitution of mechanics of granular materials through the graph theory. In: Proceedings of U.S.-Japan Seminar on Continuum Mechanical and Statistical Approaches in the Mechanics of Granular Materials Sendai, pp. 203–215 (1978)Google Scholar
- 34.Wan, R., Pinheiro, M.: Fabric and connectivity as field descriptors for deformations in granular media. Continuum Mech. Thermodyn. 27(1–2), 243–259 (2014)Google Scholar
- 36.Weber, J.: Recherches concernant les contraintes intergranulaires dans les milieux pulvérulents. Bul. Liaison P. et Ch 2(64), 170 (1966)Google Scholar