Journal article
An acoustic jack to assess in situ rock behaviour
International journal of rock mechanics and mining sciences & geomechanics abstracts, v 22(1), pp 21-29
1985
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
The determination of the
in situ stresses in rock is an important factor in the proper design of any structure founded on or within the rock mass. Of the many techniques available for its determination (all having certain advantages and disadvantages), one based on noise measurement during deformation has not yet been explored. This paper represents a first attempt in this regard.
The technique uses acoustic emission (AE) monitoring in conjunction with a borehole rock jack. This modified rock jack pressurizes the borehole walls and monitors both the induced deformation and the AE activity. The pressure, applied at a constant rate, should produce emissions at a uniform rate, unless the rock has been previously stressed. In this case, a discontinuously increased emission rate occurs beyond the previously applied stress. This test method has been performed on five massive blocks of quarry rock. These tests show that:
•
in a cyclic stress test, previous stress levels can be discerned by a sudden AE rate increase as the stress on a particular cycle exceeds the previous applied stress;
•
in three out of four constant stress rate tests, anomalous behaviour in the form of discontinuous AE rate increases were observed in the 3.0–4.0 MPa range;
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other rate changes were observed (both increases and decreases) but were at significantly higher stress levels, i.e. above 12.5 MPa.
The final device, which we call an “acoustic rock jack”, is being further tested in the field in boreholes and the AE concepts are being further evaluated and refined in laboratory studies.
Metrics
Details
- Title
- An acoustic jack to assess in situ rock behaviour
- Creators
- J.J. McElroy - Drexel UniversityR.M. Koerner - Drexel UniversityA.E. Lord - Drexel University
- Publication Details
- International journal of rock mechanics and mining sciences & geomechanics abstracts, v 22(1), pp 21-29
- Publisher
- Elsevier
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- [Retired Faculty]
- Web of Science ID
- WOS:A1985ACF2300002
- Scopus ID
- 2-s2.0-0022010360
- Other Identifier
- 991019173728104721
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InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Web of Science research areas
- Engineering, Geological
- Mining & Mineral Processing