This thesis addresses the concept of non-destructive rock mass characterisation using in-situ measurements of the velocity and attenuation of seismic waves. The thesis is divided in to two sections, the first of which considers a comprehensive laboratory study of the phenomena of stress-induced velocity and attenuation anisotropy, whilst the second documents a number of field case studies. In the first section, a review is given of the current experimental evidence and theoretical explanations of the factors that affect the propagation of seismic waves. A description is given of the spectral ratio technique for the laboratory determination of P-wave attenuation in rock core samples. The section concludes with the presentation of the results of an investigation of stress-induced velocity and attenuation anisotropy in intact samples, samples induced to failure, and fractured samples. Experimental results show that in-situ measurements of the change in velocity and attenuation could be used to predict stress change in a homogenous rock mass which contains infrequent, isolated fractures. The prediction would be based on laboratory measurements of stress-induced attenuation anisotropy in intact samples. In the second section, a new variant of seismic tomography called Combined Transmission and Reflection Tomography (CTRT) is fully described. In the chapters following this, a number of field cases are documented to show how the technique can be used to identify geological structure such as general stratigraphy, faults, orebody volumes, and man-made features such as old workings and blast induced fracture zones. The technique is shown to be ideal for surveying inaccessible areas and improving tomograms above those that can be produced by the popular transmission tomography algorithms. A final case study considers the use of seismic measurements in the prediction of rock mass behaviour in the footwall of a mine stope. The simple technique described successfully identified fault zones in two stopes before mining commenced, one of which resulted in the subsequent loss of a stope half way through mineral extraction. In conclusion this thesis comprehensively describes how seismic measurements can be used to characterise a rock mass and lays the foundations for using the same measurements for monitoring and predicting rock mass behaviour in active environments.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:548799 |
| Date | January 1996 |
| Creators | Pearce, Dominic Robert |
| Publisher | University of Leeds |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://etheses.whiterose.ac.uk/2431/ |
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