Effect of confining pressure on strain localization of a sand specimen under plane strain condition

In the present study, instability in the form of strain localization has been analyzed for drained sand specimen at different density states with varying confining pressure. The instability analysis has been posed as a plane strain bifurcation problem from a uniform stress-strain condition and the onset of strain localization is identified from the condition of loss of ellipticity of the acoustic tensor. The problem is formulated within a rate independent framework employing a generalized 3D non-associative constitutive relation. The generalized constitutive relation accounts for intermediate principal stress evolution under plane strain condition, which is simulated in this analysis through a biaxial test configuration. This study attempts to examine the sensitivity of such generalized 3D constitutive model in predicting the effect of confining pressure on the localization onset and band angle orientation of drained sand specimen at different density states. © 2015 Taylor & Francis Group, London.