Laboratory-based drop testing of rock reinforcement

Authors: Knox, G

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DOI https://doi.org/10.36487/ACG_repo/2325_0.02

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Knox, G 2023, 'Laboratory-based drop testing of rock reinforcement', in J Wesseloo (ed.), Ground Support 2023: Proceedings of the 10th International Conference on Ground Support in Mining, Australian Centre for Geomechanics, Perth, pp. 23-38, https://doi.org/10.36487/ACG_repo/2325_0.02

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Abstract:
The requirement for resources has resulted in mining activities moving into more challenging conditions, from conventional, gravity driven ground conditions to highly stressed rock mass. In highly stressed, burst-prone rock masses, mining-induced seismicity presents a challenge to most ground support systems. The capacity of conventional rock reinforcement elements such as grouted rebar rockbolts and friction rockbolts is often found to be inadequate when subjected to large deformations resulting from mining-induced seismicity. The requirement to sustain large loads over large deformations has led to the development of several energyabsorbing rock reinforcement elements. The performance of an energy-absorbing element is typically determined through a laboratory-based drop test. During a laboratory-based test, the kinetic energy of a known mass, released from a known height, is transferred to the rock reinforcement element installed in a steel tube. There are two primary drop test methods, impact testing and momentum transfer. Although there are arguably differences between the two methods, both share common limitations. This paper provides a summary of recent investigations conducted to understand the effect of the test parameters on the performance of rock reinforcement elements determined through laboratory-based drop testing. The purpose is to provide a high-level overview rather a detailed review.

Keywords: drop testing, impact testing, momentum transfer, rock reinforcement elements

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