Dynamic assessment of ground support schemes: insights from comprehensive full-scale testing

Authors: Brändle, R; Roth, A Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2465_07

Cite As:
Brändle, R & Roth, A 2024, 'Dynamic assessment of ground support schemes: insights from comprehensive full-scale testing', 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. 195-206, https://doi.org/10.36487/ACG_repo/2465_07



Abstract:
Rock ejection from dynamic loading poses significant risks in underground mining and tunnelling operations. In order to mitigate these risks and ensure a safe working environment, surface support systems such as steel mesh are crucial in containing any rock failures or ejections. This research presents findings from a comprehensive test series conducted in Walenstadt, Switzerland to assess the effectiveness of ground support schemes using different types of steel mesh and bolts under dynamic conditions. The test rig was designed to apply large amounts of energy to various support systems with different bolt patterns and mesh types at full scale. The behaviour of the systems was analysed using load cells, high-speed video analysis and accelerometers. Different set-ups with typical reinforcement elements have been tested, where the focus has been on developing a test method which reflects a realistic load transfer scenario. For that purpose, tests with different energy levels have been carried out and analysed. The main objective of the tests has been to investigate the energy dissipation of specific support elements if tested in a full system. Based on that, energy dissipation ratings (in kJ/m2) in different areas of the complete scheme can be assessed. Varying the impact energies allows investigation of the increasing load distribution in the scheme and helps to identify residual capacities and residual safety after a dynamic event. This will help to develop a design concept for site-specific ground support schemes. In summary, this paper offers significant insights into the load-bearing characteristics of typical ground support schemes under dynamic conditions and highlights the crucial role of a system-based approach in their design. The outcomes of the comprehensive test set-up and advanced analysis of various impact scenarios can aid in the development of more efficient and effective surface support systems, as well as a suitable design concept, ultimately resulting in safer and more productive mining operations.

Keywords: ground support testing, mesh overlap, full-scale tests, chain-link mesh

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