Brittle failure in compression: splitting faulting and brittle-ductile transition

Abstract

The micromechanics of brittle failure in compression and the transition from brittle to ductile failure, observed under increasing confining pressures, are examined in the light of existing experimental results and model studies. First, the micromechanics of axial splitting and faulting is briefly reviewed, certain mathematical models recently developed for analysing these failure modes are outlined, and some new, simple closed-form analytic solutions of crack growth in compression and some new quantitative model experimental results are presented. Then, a simple two-dimensional mathematical model is proposed for the analysis of the brittle—ductile transition process, the corresponding elasticity boundary-value problem is formulated in terms of singular integral equations, the solution method is given, and numerical results are obtained and their physical implications are discussed. In addition, a simple closed-form analytic solution is presented and, by comparing its results with those of the exact formulation, it is shown that the analytic estimates are reasonably accurate in the range of the brittle response of the material. Finally, the results of some laboratory model experiments are reported in an effort to support the mathematical models.

Influence of Sample Height-to-Width Ratios on Failure Mode for Rectangular Prism Samples of Hard Rock Loaded In Uniaxial Compression

“…On the one hand, the present studies on slabbing failure of hard rocks mainly concentrate on the description of slabbing phenomenon and how to control slabbing failure in situ (Dowding and Andersson 1986;Fang and Harrison 2002;Martin et al 1997). On the other hand, most studies are concerned with shear failure of hard rock (Bieniawski 1967a, b, c;Brady and Brown 2004;Lockner et al 1991;Mogi 2007;Moore and Lockner 1995;Savage et al 1996) except for a few studies on splitting failure (Holzhausen and Johnson 1979;Horii and Nemat-Nasser 1986;Li Chunlin 1995;Wong et al 2006) in the laboratory compression tests.…”

A Damage Constitutive Model for Rock Mass with Nonpersistently Closed Joints Under Uniaxial Compression

“…where a is half length of the joint, and l * = 0.27a was introduced [30] to make K I and K II nonsingular when the tensile crack length is small. l is the propagation length of the wing cracks.…”

Numerical Analysis of Failure Process of Intermittent Single Jointed Rock Mass Based on Potential Energy Dissipating Principle

“…Cook, Kemeny, Hoek [1][2][3][4] according to the theory of fracture machanics did research on rock crack extension under stressful situation. Horii H, Ashby M F, Wang Gengsun, Li Shucai [5][6] studied the linking mechanism of multiple crack under condition of single and biaxial, which points out that the macro damage is mainly related to the crack distribution, lateral pressure and transfixion crack.…”