3 - Constitutive Models of Rock Fractures and Rock Masses – The Basics

Abstract

This chapter presents the fundamental aspects of mathematical theories relating to the mechanical behavior of rock fractures and rock masses, including the most commonly encountered criteria for shear strength and constitutive models for rock fractures, and constitutive models for rock masses based on the theory of elasticity, elastoplasticity, and the crack tensor concept. Although tremendous efforts have been made to develop constitutive models for rock fractures, the presently available models still have significant limitations in predicting fracture behavior with an adequate level of confidence. The major difficulty is the lack of unique and quantitative representation of fracture surface roughness, confident prediction of surface damage evolution during a general deformation process, and its impact on the thermo-hydro-mechanical coupling processes and properties of rock fractures. Other difficulties include the models for large-scale features, such as faults or fracture zones with large widths, time-scale dependence and hydro-mechanical coupling effects.