Effect of rock microfabric on the brittle failure process of rocks stressed under simulated laboratory conditions

Relationships will be studied between stress-strain behaviour, the acoustic emission and microcrack propagation. The experimental study of the relationship between rock microfabric and modes of failure has direct effect on the solution of some problems of underground excavations' stability (mining, radioactive waste repositories construction, stability of underground engineering structures). Statistical autocorrelation analysis of acoustic emission events will facilitate determination of initial stress-state of the rock sample or rock mass, respectively. It is supposed that independent method - frequency analysis of radiated acoustic events - will confirm results of autocorrelation analysis. Analysis of radiated signals (first on-sets of the P-waves) will help interpretation of failure mechanism. The direct methods (mainly computer assisted image analysis, visualisation of brittle fractures in deformed rock samples) for evaluation of microcrack initiation and crack damage stress levels will