Energy-absorbing rockbolt behaviour under combination loading angle configurations

Authors: Hadjigeorgiou, J; Knox, G Download Paper

DOI https://doi.org/10.36487/ACG_repo/2625_31

Cite As:
Hadjigeorgiou, J & Knox, G 2026, 'Energy-absorbing rockbolt behaviour under combination loading angle configurations', in D Cumming-Potvin & J Wesseloo (eds), Ground Support 2026: Proceedings of the 11th International Conference on Ground Support in Mining, Australian Centre for Geomechanics, Perth, pp. 1-12, https://doi.org/10.36487/ACG_repo/2625_31



Abstract:
Energy-absorbing rockbolts are applied in ground conditions where large deformations are anticipated. In such conditions, it is expected that the rockbolt may be subjected to multiple loading configurations ranging from axial through to shear. The relationship between the loading angle and energy capacity of a rockbolt represents a knowledge gap that may account for the difference in performance observed in the field and recorded in the laboratory testing. This paper investigates the mechanical behaviour of energy-absorbing rockbolts under quasi-static loading for a range of loading angles. A combination shear and tensile pull test rig was employed to simulate axial (0°) combination shear and loading with resultant loading angles (30 and 60°) and shear loading (90°) All selected rockbolts employed the ‘steel stretching’ mechanism whereby energy is dissipated through the plastic deformation of the bar between two anchor points bounding the loaded section. This includes paddled energy-absorbing, yielding mechanical hybrid and energy-absorbing self-drilling rockbolt types. The results identified variations in performance as a function of loading angle for all rockbolt types. In addition, the presence or absence of a chemical anchoring medium was identified as a critical factor in the response of the rockbolts to combination loading. The results provide the means for a data driven design approach recognising difference in behaviour of energy-absorption rockbolts under complex loading quasistatic loading conditions.

Keywords: energy-absorbing rockbolts, quasi-static loading, combined loading configurations, steel stretching mechanism

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