ABSTRACT
The mechanism which controls violent/non-violent rock failure is studied through an extensive experimental study through uniaxial and triaxial compression loading. The tests were undertaken under quasi-static and post-peak cyclic loading. Axial displacement control system can be employed to measure the post-peak response of the rocks only if the rock demonstrates class I behaviour. Lateral strain control loading system, however, is applicable to measure true post-peak rock behaviour when they exhibit class II behaviour. It was observed that post-peak behaviour of rocks is an intrinsic property and independent of loading condition. In the triaxial compressive testing when the ratio between confining pressure to the unconfined compressive strength increases, rock post-peak behaviour shifts from class II behaviour to class I behaviour. Rock samples with a higher aspect ratio were observed to behave more brittle. The effect of scale on the post-peak response of rock, however, is found to be insignificant.
