SEDL / STP / STP1077-EB / STP19108S

Acoustic Emission Analysis and Ultrasonic Velocity Imaging in the Study of Rock Failure

Falls, SD
Rock Physics and Engineering Seismology Laboratory, Department of Geological Sciences, Queen's UniversityQueen's University, Kingston,

Chow, T
Rock Physics and Engineering Seismology Laboratory, Department of Geological Sciences, Queen's UniversityQueen's University, Kingston,

Young, RP
Rock Physics and Engineering Seismology Laboratory, Department of Geological Sciences, Queen's UniversityQueen's University, Kingston,

Hutchins, DA
Rock Physics and Engineering Seismology Laboratory, Department of Geological Sciences, Queen's UniversityQueen's University, Kingston,

Pages: 11    Published: Jan 1991

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Abstract

Two methods were used to examine the effects of stress changes and microfracture activity during Brazilian disk tests performed on Lac du Bonnet Granite. Acoustic emission analyses examining source locations and source mechanisms led to two main findings. Firstly, the sources were clustered in the regions with the greatest difference between the minimum and maximum principal stresses. Secondly many sources involved some degree of shear motion. This indicates that dilatancy in these rocks may be largely controlled by hybrid shear-tensile microfractures. Ultrasonic tomographic imaging of p-wave speed was the second technique used to study stress induced effects on the samples. The images created have successfully delineated areas of the rock with high stress concentrations.