3D bifurcation analysis in geomaterials

Abstract

ABSTRACT In this paper, a study of failure in geomaterials is proposed using the second order work criterion and a phenomenological approach. In a first part, an analytical investigation of this criterion is proposed. General 3D equation of instability cones as well as of the 3D bifurcation domain limit are given for every incrementally piece-wise linear constitutive model. In the second part, these instability cones and bifurcation domain are displayed for constitutive models of Darve. Then a physical interpretation of these results is proposed. Noticeably, it is proved that, when the second order work vanishes along a given loading path, an extension a generalized flow rule can be defined for proper conjugated variables. Finally we conclude that this approach constitutes a good starting point when investigating bifurcation in geomaterials, and opens new horizons in experimental testing.