ABSTRACT
The monitoring of acoustic emission activity produced during deformation is one of the well-known methods for observing material damage. Kaiser (1950) discovered that the acoustic emission, AE, from a stressed metal sample is zero if the applied stress is less than the previously applied maximum stress, a phenomenon now termed the Kaiser Effect. The potential value of this effect in rock mechanics is the possibility of establishing the in situ stresses in a rock mass by measuring the acoustic emission from site investigation cores loaded in uniaxial compression and establishing the applied stress at which significant acoustic emission begins to occur. Because the quantity ‘stress’ is a second order tensor with six independent components, it is essential that such tests for any specific core location are conducted on at least six sub-cores taken from the main core.
