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BEHAVIOUR OF ISOTROPIC ROCK MATERIAL IN UNIAXIAL COMPRESSION
Figure 4.10 Axial stress, a , and
radial strain, ε r , vs. axial strain, ε a , not reproduced in practical mining problems, this approach does permit progressive
curvesrecordedinauniaxialcompres- post-peak breakdown to be controlled and studied.
sion test on an oolitic limestone (after Figure 4.11 shows the complete a –ε a curves obtained by Wawersik and Fairhurst
Elliott, 1982).
(1970) in a series of controlled uniaxial compression tests on a range of rock types.
By halting tests on specimens of the same rock at different points on the curve
and sectioning and polishing the specimens, Wawersik and Fairhurst were able to
study the mechanisms of fracture occurring in the different rock types. They found
that the post-peak behaviours of the rocks studied may be divided into two classes
Figure 4.11 Uniaxial stress–strain
curves for six rocks (after Wawersik
and Fairhurst, 1970).
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