Acoustic Emission as an Indicator of Macrofailure of Rock

Ghosh, A. (Southwest Research Institute) | Hsiung, S.M. (Southwest Research Institute)



Cracks develop in brittle materials under compressive load as a result of growth of microcracks causing irreversible damage and produce acoustic emission (AE). At high applied load, this damage causes strain localization leading to the ultimate fracture plane. Laboratory studies are used to investigate the fracturing process in a brittle rock to identify the precursory sequences of a rockburst or an earthquake. In this study, the objective was to develop a methodology to predict the ultimate fracture in laboratory-scale rock specimens of Apache Leap tuff by monitoring the clustering phenomenon of the AEs. Multifractal analysis of spatial distribution of the AEs, collected in laboratory experiments under uniaxial compression, indicates that the time for development of an ultimate failure plane can be identified through a sharp decrease in the fractal dimension. Clustering of seismic events at a particular location indicates the location of the failure plane.