A continuum model for plastic-brittle behaviour of rock and concrete

Abstract

The present work deals with a continuum model for time-independent behaviour of progressively fracturing solids. The rate theory with fracture parameter is discussed and applied to rock-like materials. In particular, elastic-brittle and plastic-brittle idealizations are considered with the fracturing affecting elastic and plastic strains, respectively. The elastic-brittle model incorporates, however, the plasticity-like concept of varying fracture surface. Also the idea of a limit (failure) locus is introduced as the stress-path dependent condition, instead of being prescribed a priori. The plasticity model attempts to cover both stable and unstable portions of the stress-strain relation while the fracture parameter is coupled with irreversible volumetric dilatancy. The general model is applicable to wider class of engineering materials, ƒ. ex. to metals in advanced yielding accompanied with microfracturing.