ABSTRACT
Taking all of these factors into account, it can be seen that a rock failure criterion which will be of significant use to the underground excavation designer should satisfy the following requirements :
Axial stress
Axial strain Stress-strain curves for brittle fracture in uniaxial compression
Axial stress
Ductile
Z Brittle-due tile
transition
Axial strain
Stress-strain curves for ductile behaviour in compression
Brittle and ductile behaviour
Figure 64 : Uniaxial tensile test arrangement suggested by Hawkes and Mellorl2&.
