Conference Proceedings
The Australasian Ground Control Conference An ISRM Regional Symposium (AusRock Conference) 2022
Conference Proceedings
The Australasian Ground Control Conference An ISRM Regional Symposium (AusRock Conference) 2022
Support structure design for rock burst damage restraint initiated by a low-intensity seismic wave
Deep hard rock underground mines tend to experience high stress as such drives exhibit dynamic responses attributed to a rock burst variant (strainburst). This dynamic behaviour is difficult to predict, and every effort is made to devise the appropriate dynamic support system for its associated failure restraint. This paper outlines the back analysis and the support scheme design for an underground decline that exhibited damage from a dynamic strainburst occurrence. It employs a decline section that experienced a dynamically loaded strainburst that initiated rock fragment ejections. The procedure involves a preliminary structural analysis, a seismic intensity measure, and a rock mass simulation to determine the static stress concentration and ground support system response. The numerical simulation is conducted in FLAC3D which employs the advanced strain-softening IMASS constitutive model governed by two HoekβBrown (HB) bounding yield surfaces. To account for the post-peak brittleness response associated with strainburst the plastic strain multiplier (πΊπΊππππππππ) is adjusted to 0.0 < πΊπΊππππππππ< 1.0. The back-analysis shows that the occurrence was initiated by a low_x0002_intensity seismic wave that superimposed an extra stress component to the initial static stress which triggered rock fragment ejections. Additionally, the appropriate support scheme comprised of Weldmesh, Fibrecrete, static (split set) and yieldable (Kinloc) reinforcements is recommended and implemented. Thereafter, the boltβs efficiency is evaluated based on the axial force and elongation capacities and then compared with the published bolt performance data. The evaluation results show that the maximum bolt axial force (0.1 per cent) and elongation (0.006 per cent) are below the designed capacity and rupture strain.
Contributor(s):
E Kabwe and M Karakus
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Support structure design for rock burst damage restraint initiated by a low-intensity seismic wavePDFNormal price $22.00Member price from $0.00
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- Published: 2022
- Pages: 25
- PDF Size: 2.537 Mb.
- Unique ID: P-02406-F7L2X2