DOI https://doi.org/10.36487/ACG_repo/2645_80
Cite As:
Knox, G & Hadjigeorgiou, J 2026, 'Influence of testing configuration on the behaviour of energy-absorbing,
self-drilling rockbolts under impact loading', in A van As, D Cumming-Potvin & J Wesseloo (eds),
Caving 2026: Proceedings of the Sixth International Conference on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, pp. 1-15,
https://doi.org/10.36487/ACG_repo/2645_80
Abstract:
A major challenge in block caving operations is the selection of ground support that can accommodate the deformation associated with the significant stress changes during the life of an operation. This is best accomplished using high energy-absorbing rockbolts. An additional operational constraint is the installation of the selected rockbolts in heavily fractured or poor ground conditions. Under these constraints, the use of energy-absorbing, self-drilling rockbolts becomes an attractive option.
The ISRM suggested method for determining the performance of energy-absorbing rockbolts in the laboratory relies on dropping a given mass from a specific height employing 2 testing configurations to transfer the kinetic energy of the falling mass to the rockbolt that is installed in a steel tube. The continuous tube configuration simulates an impact load directly applied onto the rockbolt plate while the split tube represents a loading condition on a rockbolt when a rock block is ejected by an impact thrust. The in situ loading of a rockbolt under seismic loads is more complex. This paper investigates the influence of the split location along the testing tube on the behaviour of energy-absorbing, self-drilling rockbolts. The results of this experimental program demonstrated that the location of the split within the host tube controlled both the maximum plate displacement and dissipated energy recorded prior to the rupture of the rockbolt. These additional loading configurations contribute to an improved understanding of the behaviour of Energy-absorbing Self-drilling Rockbolts under impact loading. This has significant practical implications for the selection and design of ground support in block caving operations.
Keywords: hollow core rockbolts, impact testing, split location
References:
Abreu, R & Knox, G 2022, ‘The influence of drilling on the performance of a yielding self-drilling rockbolt’, in Y Potvin (ed.), Caving 2022: Proceedings of the Fifth International Conference on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, pp. 165–176,
Bray, P, Johnsson A, & Shcunnesson, H 2019, ‘Rock reinforcement solutions case study: Malmberget iron ore mine, Sweden’, in W Joughin (ed.), Proceedings of the Ninth International Conference on Deep and High Stress Mining The Southern African Institute of Mining and Metallurgy, Johannesburg, pp. 191–204.
Epiroc 2022, BoraBolt, viewed 20 May 2022,
Evans, DW 2022, ‘Data cross validation for a newly commissioned dynamic drop test facility’, Proceedings of The Fifth Australasian Ground Control in Mining Conference Proceedings, The Australasian Institute of Mining and Metallurgy, Melbourne, pp. 320–328.
Faulkner, D, Stankus, J, Ma, K & Ma, L 2017, ‘Multiple point anchor (MPA), self-drilling, hollow core yielding bolt with injectable J-lok P resin system for high-stress and squeezing ground conditions’, Proceedings of the 51st U.S. Rock Mechanics/Geomechanics Symposium, American Rock Mechanics Association, Alexandria.
Hadjigeorgiou, J 2024, ‘Inconvenient truths about ground support in deep and high-stress mines’, in P Andrieux & D Cumming-Potvin (eds), Deep Mining 2024: Proceedings of the 10th International Conference on Deep and High Stress Mining, Australian Centre for Geomechanics, Perth, pp. 23–60,
Holden, M, Akdag, S, Chengguo, Z, Oh, J, Saydam, S, Galluzzi, R & MacDonald, D 2024, ‘Dynamic performance testing and numerical modelling of the falcon bolt’, in New Challenges in Rock Mechanics and Rock Engineering, CRC Press, Boca Raton, pp. 859–865.
Jennmar 2022, MPA Bolt System, viewed 20 May 2022,
Jennmar 2024, MPA Bolt System Brochure,
Jere, P, Battison, R & Arnold, M 2023, ‘Performance of fully mechanised rock reinforcement using self-drilling anchors’, in Underground Operators Conference 2023: Conference Proceedings, Australasian Institute of Mining and Metallurgy, Melbourne, pp. 258–268.
Knox, G & Berghorst, A 2018, ‘Increased agility for the research and development of dynamic roof support products’, in CC Li, XB Li & ZX Zhang (eds), Proceedings of Rock Dynamics – Experiments, Theories and Applications, CRC Press, Trondheim, pp. 373–384.
Knox, G & Hadjigeorgiou, J 2022, ‘Influence of testing configuration on the performance of paddled energy-absorbing rockbolts under impact loading’, Rock Mechanics and Rock Engineering, vol. 55, pp. 5705–5721.
Knox, G & Hadjigeorgiou, J 2023, ‘Performance of conventional and energyabsorbing selfdrilling hollow core rockbolts under controlled laboratory conditions’, Rock Mechanics and Rock Engineering, vol. 56, pp. 4363–4378.
Li, C 2010, ‘A new energy-absorbing bolt for rock support in high stress rock masses’, International Jounrnal of Rock Machanics & Mining Sciences, vol. 47, pp. 396-404.
Li, CC & Doucet, C 2012, ‘Performance of D-bolts under dynamic loading conditions’, Rock Mechanics and Rock Engineering, vol. 45, pp. 193–204.
Li, C, Hadjigeorgiou, B, Mikula, P, Knox, G, Darlington, B, Royer, R … Hosp, M 2021, ‘Performance of identical rockbolts tested on four dynamic testing rigs employing the direct impact method’, Journal of Rock Mechanics and Geotechnical Engineering, vol. 13, no. 4, pp. 745–754.
Minova 2026, Uni-pass Bolting System, viewed 29 June 2026,
Normet 2026, Self-Drilling Anchors, viewed 29 June 2026,
Player, JR 2012, Dynamic Testing of Rock Reinforcement Systems, PhD thesis, Curtin University of Technology, Perth.
Punkkinen, A & Royer, R 2022, ‘Performance of Normet self drilling dynamic bolt (SDDB) types in dynamic loading - the energy dissipating hollow core rockbolt installed in Norment’s urea-silicate injection resin’, in RASIM2022, Society for Mining, Metallurgy & Exploration, Englewood.
Simser, BP 2007, ‘The weakest link - ground support observations at some Canadian Shield hard rock mines’, in Y Potvin (ed.), Deep Mining 2007: Proceedings of the Fourth International Seminar on Deep and High Stress Mining, Australian Centre for Geomechanics, Perth, pp. 335–348,
Vallati, O, Darlington, B & Sandberg, L 2022, ‘Dynamic drop testing of Sandviks D47 and D39 MDX bolts at the Swerim’s testing facility’, Proceedings of The Fifth Australasian Ground Control in Mining Conference Proceedings, The Australasian Institute of Mining and Metallurgy, Melbourne, pp. 428–440.
Watt, G, Roberts, T & Faulkner, D 2018, ‘Single pass drill, install and inject self-drilling resin bolt applications in poor ground’, Proceedings of The Fourth Australasian Ground Control in Mining Conference Proceedings, The Australasian Institute of Mining and Metallurgy, Melbourne, pp. 323–343.