Crompton, BR & Knox, G 2022, 'Dynamic testing: determining the relationship between rockbolt diameter and the residual dynamic capacity of an axially strained tendon', in Y Potvin (ed.), Caving 2022: Fifth International Conference on Block and Sublevel Caving
, Australian Centre for Geomechanics, Perth, pp. 141-150, https://doi.org/10.36487/ACG_repo/2205_07
The specification of a tendon is stated as the capacity of the tendon in new condition on the day it was produced. Rock support tendons are discretely tested quasi-statically (replicating closure) or dynamically (replicating seismicity) depending on the conditions expected with the mine environment. Although this testing is valuable, it is likely that a tendon subjected to rapid ground movement (seismicity) would first be subjected to some level of slow closure. Previous research investigated the possible correlation between the quasi-static elongation of a rockbolt prior to dynamic loading and residual dynamic capacity. The results from this research indicated that a correlation exists between the residual dynamic capacity and the energy absorbed quasi-statically when the tendon is elongated axially. It was proposed that a conservative approach would be to consider the total energy capacity of a tendon as the energy absorbed by a tendon in pristine condition during a single dynamic impulse resulting in the rupture of the tendon. The research sample set was limited to a single rockbolt configuration of fixed length and diameter, therefore it was noted that the results should not be extrapolated to other versions of this system or other ground support systems.
This research will build on the previous work by repeating the testing regime on a larger diameter of the same configuration rockbolt. The results will be analysed to identify how the diameter of a rockbolt affects the energy and elongation capacity of the rockbolts under combined quasi-static and dynamic loading. This information will greatly assist geotechnical practitioners with support system design, product selection and decisions on when to rehabilitate an installed support system.
Keywords: dynamic testing, ground support, pre-elongated, squeezing ground, seismicity, rockbolt, PAR1 Resin Bolt, Dynamic Impact Tester
Bosman, K, Cawood, M & Berghorst, A 2018, ‘The relationship between the magnitude of input energy per impulse and total absorbed energy’, Proceedings of the 3rd International Conference on Rock Dynamics and Applications (RocDyn-3), CRC Press, Trondheim, pp. 379–384.
Epiroc 2022, PAR1 Resin Bolt, Stockholm, viewed 4 May 2022,
GMA AB 2021, GMA AB launches it’s own dynamic rock bolt – the GE bolt, Luleå, viewed 4 May 2021,
Hadjigeorgiou, J & Potvin Y 2011, ‘A cirtical assessment of dynamic rock reinforcement and support testing facilites’, Rock mechanics and rock engineering, vol. 44, no. 5, pp. 565–578.
Hadjigeorgiou, J 2016, ‘Rock support: degradation and failure’, Proceedings of the 8th International Symposium on Ground Support in Mining and Underground Construction, Luleå University of Technology, Luleå, pp. 1–22.
Jager, AJ 1992, ‘Two New Support Units for the Control of Rockburst Damage’, in PK Kaiser & DR McCreath (eds.), Rock Support in Mining and Underground Construction, Balkema, Rotterdam, pp. 621–631.
Knox, G & Berghorst, A 2018, ‘Increased agility for the research and development of dynamic roof support products’, Proceedings of RocDyn-3, Trondheim, Norway, pp. 373–384.
Knox, G & Berghorst, A 2019, ‘Dynamic testing: determining the residual dynamic capacity of an axially strained tendon’, Proceedings of Ground Support 2019, Australian Centre for Geomechanics, Perth, pp. 231–242.
Li, C & Doucet, C 2012, ‘Performance of the D-bolt under dynamic loading conditions’, Rock mechanics and rock engineering, vol. 45, pp. 193–204.
Li, CC 2017, Rockbolting: Principles and Applications, Butterworth-Heinemann, Oxford.
Louchnikov, V & Sandy, MP 2017, ‘Selecting an optimal ground support system for rockbursting conditions’, in J Wesseloo (ed.), Deep Mining 2017: Proceedings of the Eighth International Conference on Deep and High Stress Mining, Australian Centre for Geomechanics, Perth, pp. 613–623,
Mansour Mining Technologies 2021, Mansour Mining Technologies inc. Product Catalogue, viewed 5 April 2022,
Normet 2022, Normet D-Bolt® – Dynamic rock bolt, viewed 5 April 2021,
Ortlepp, WD 1969, ‘An Empirical Determination of the Effectiveness of Rockbolt Support under Impulse Loading’, in TL Brekke & FA Jorstad (eds.) Proceedings of the International Symposium on Large Permanent Underground Openings. Universitatsforlaget, Oslo, pp. 197–205.
Potvin, Y & Hadjigeorgiou, J 2020, Ground Support for underground mines, Australian Centre for Geomechanics, Perth.
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,
Tonry Mining 2022, Dynamic Energy Absorbing Bolt (E-Bolt), viewed 5 April 2022,
Villaescusa, E, Thompson, A & Player, J 2004, ‘Dynamic Testing of Rock Reinforcement using the Momentum Transfer Method’, in E Villaescusa & Y Potvin (eds) Ground Support in Mining and Underground Construction, CRC Press, London, pp. 237–339.