- Title
- Shear strength characterisation for very-high coal mine spoil dumps: Applicability of an industry-accepted framework
- Creator
- Bradfield, L. R.; Fityus, S. G.; Simmons, J. V.
- Relation
- 53rd U.S. Rock Mechanics/Geomechanics Symposium. Proceedings of 53rd U.S. Rock Mechanics/Geomechanics Symposium (New York, NY 23-26 June, 2019) p. 3977-3991
- Publisher
- American Rock Mechanics Association
- Resource Type
- conference paper
- Date
- 2019
- Description
- Selection of appropriate shear strength parameters for mine spoil slope stability analysis and design is difficult because it requires prohibitively large laboratory equipment to test characteristic spoil samples under meaningful stresses. A convenient alternative to estimate mine spoil shear strength is to adopt published guidelines that have been tried-and-tested in practice. For more than two decades, the Australian coal mining industry has adopted a linear shear strength framework derived from small-scale test data and verified in practice by slope performance of dragline-scale spoil dumps up to 120m in height, and to date this framework has appeared reliable. However, in the field of rockfill dam design there is a broad acceptance of a curvilinear shear strength envelope, and if this is applicable to coal mine spoils, then this industry-accepted framework may overestimate the strength and stability of dumps at higher stress levels. This is particularly relevant in modern times where dump heights (>350m) often exceed the scale (=120m) for which the framework was developed. This paper explores the applicability of this framework for high-dump situations for a range of coal mine spoils. This is achieved by comparing their framework-assigned strength envelopes with direct measurements of their strength obtained from a custom-built large direct shear machine (LDSM). The machine can test at a much larger scale, in terms of combined specimen size (720mm x 720mm x 600mm) and stress (s’n up to 4.6MPa) than has ever been achieved using a direct shear machine for geotechnical testing of rockfill. A critical outcome is that the LDSM data highlights several non-compliant mine spoils, and stress-dependent shearing behaviour, for which correct application of the published framework will not provide reliable shear strength parameters for design.
- Subject
- reservoir characterization; strength; upstream oil & gas; reservoir geomechanics; metals & mining; bmac framework
- Identifier
- http://hdl.handle.net/1959.13/1460197
- Identifier
- uon:45889
- Identifier
- ISBN:9781510894068
- Language
- eng
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