Stick-slip behaviour of model granular materials in drained triaxial compression

• Published in: Granular matter Vol. 15; no. 1; pp. 1 - 23
• Main Authors: Doanh, T., Hoang, M. T., Roux, J.-N., Dequeker, C.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.02.2013; Springer Nature B.V; Springer Verlag
• Subjects: Axial strain; Beads; Complex Fluids and Microfluidics; Dynamical systems; Dynamics; Engineering Fluid Dynamics; Engineering Sciences; Engineering Thermodynamics; Foundations; Geoengineering; Geophysics; Glass; Heat and Mass Transfer; Hydraulics; Industrial Chemistry/Chemical Engineering; Instability; Materials; Materials Science; Original Paper; Physics; Physics and Astronomy; Shear strength; Soft and Granular Matter; Stability; Strain rate; Stress-strain relationships; Stick-slip; Triaxial compression; Friction; Model granular materials; Dilatancy
• ISSN: 1434-5021; 1434-7636
• DOI: 10.1007/s10035-012-0384-6

Drained triaxial axisymmetric compression tests are performed on water-saturated short cylindrical samples of nearly monodisperse glass beads, initially assembled in a loose state by a moist tamping technique. Both deviator stress and volumetric strain , measured as functions of axial strain , for different strain rates, are affected by stick-slip events of very large amplitude, while the classical behavior of loose, contractant granular assemblies, approaching the critical state for large , corresponds to the upper envelop of the stress-strain behaviour. Those events consist in a very fast ( slip ) part in which a drop of coincides with a jump of (contraction), while loss of control of and generation of pore pressure signal a dynamic collapse of the material structure triggered by an instability; and then a quasi-static ( stick ) part in which the sample regains its strength and, over a short strain interval, behaves similarly to a denser system that dilates before reaching its critical state. A unique stress-dilatancy relation applies to all stick-slip events. Apparent internal friction angles and effects of strain rate and confining pressure are discussed, and it is argued that stick-slip instabilities originate in physico-chemical aging phenomena coupled to contact mechanics.