A model of two-phase equilibrium for formation of kink-bands in rocks
- 1 Downloads
Kink-bands in rocks have been widely observed in nature and imitated in the laboratory, and the mechanism of their formation has attracted much attention from various researchers for many years. In this paper, a two-phase equilibrium model is presented in which the kink-bands are considered as a high-strain phase and the other regions outside kink-bands as a low-strain phase and the discontinuity of the deformation gradient and stresses is permitted across the interface between those two phases. Based on the present model, we conduct the analysis for the rocks under plane strain compression by finding the minimum value of the compressive loading at which the governing equations have real, physically acceptable solutions. It is revealed that for the rocks with strain-softening behaviour, two-phase equilibrium solutions exist, and the critical value of the compressive loading, the inclination angle of the kink-band, and the stresses and strains inside and outside kink-bands can all be determined by the solution, which are in good agreement with experimental measurements and observations.
Key wordskink-band rocks strain localization two-phase equilibrium
Unable to display preview. Download preview PDF.
- Labuz, J.F. and Carvalho, F.C.S., Post-failure micromechanisms in shear banding of rock. Acoustic Emission-Beyond the Millennium, 2000: 145–158.Google Scholar
- Riedel, J.J., Labuz, J.F. and Dai, S.T., Plane strain compression of sandstone under low confinement. In: Labuz, J.F. and Drescher, A., editors. International Workshop on Bifurcations and Instabilities in Geomechanics, 2002 Jun 02–05; Minneapolis, Mn: A Balkema Publishers, 2002: 207–216.Google Scholar
- Desrues, J., Tracking strain localization in geomaterials using computerized tomography. In: Otani, J. and Obara, Y., editors. International Workshop on X-Ray CT for Geomaterials(GeoX 2003); 2003 Nov 06–07; Kumamoto, Japan: A Balkema Publishers, 2003: 15–41.Google Scholar
- Wang, X.B., Failure process and stress-strain curve of plane strain rock specimen with initially random material imperfections. In: Zhou, Y., Tu, S.T. and Xie, X., editors. Asian Pacific Conference for Fracture and Strength (APCFS’06); 2006 Nov 22–25; Sanya, Peoples R China: Trans Tech Publications, 2007: 1133–1136.Google Scholar
- Freidin, A.B. and Chiskis, A.M., Phase transition zones in nonlinear elastic isotropic materials. Part 1: Basic relations. Izvestia RAN. Mechanika Tverdogo Tela (Mechanics of Solids), 1994, 29(4): 91–109.Google Scholar
- Freidin, A.B. and Chiskis, A.M., Phase transition zones in nonlinear elastic isotropic materials. Part 2: Incompressible materials with a potential depending on one of deformation invariants. Izvestia RAN. Mechanika Tverdogo Tela (Mechanics of Solids), 1994, 29(5): 46–58.Google Scholar