Controlling behaviour of constitutive models for rocks using energy dissipations

Abstract

• For the first time, the approach proposed in this study for constitutive modelling of rocks and other similar geomaterials provides direct links between dissipative mechanisms and behaviour in both tension and compression. • Varying contributions from individual dissipative mechanisms to the total dissipative budget leads to different constitutive responses. • The established explicit links between behaviour and the underlying dissipative mechanisms help remove or minimise the number of ad hoc fitting parameters, while providing reasonable macro responses. • The proposed analytical solutions for triaxial loading conditions allow quick assessment of model behaviour, besides providing a good way to verify the numerical implementation algorithms. • The proposed framework open potentials to develop constitutive models for geomaterials to cover a wider range of scenarios in which total dissipation varies under complex loading conditions. The behaviour of rocks and other similar geomaterials is governed by different underling dissipative mechanisms that can be represented by damage and plastic strains in continuum constitutive modelling. The explicit links between these dissipative mechanisms and constitutive behaviour are established in this study in a generic thermodynamics-based framework. The key feature of this proposed framework and derived damage-plasticity models is the capability to control the constitutive behaviour through varying the contributions of different dissipative mechanisms to the total dissipation budget. Particularly, three fractions of the total dissipation budget related to damage, plastic volumetric and shear dissipations are introduced to control the constitutive behaviour through the evolution of damage variable and plastic strains, respectively. The examples provided show the performance and promising features of the proposed framework.

Topics & Concepts