An Energy-fracture Mechanics-based Viewpoint for Defining the Tensile Strength of Rock

This paper reviews the current trends in fracture mechanics and attempts to use some of its parameters on rocks. Some drawbacks of standard test methods as applied to rocks are highlighted. A Hoop specimen test is introduced as a procedure for determining the strength of a rock; the strength definition here, being central to the theme in this paper. The energy distribution in a cracking rock is used to support the notion of energy dissipation prior to macrocrack growth as being extremely relevant in quantifying a rock's strength. A Hoop specimen rather than a conventional fracture mechanics specimen is used to illustrate the concept. This concept essentially argues that conventional fracture mechanics-based characterisation of a rock's resistance to fracture might not be the most suitable. Reasons for why this is so and alternative parameters are suggested.