Case study: use of rebars with microalloyed steels in tunnels with induced seismicity

Authors: Muñoz, A; Cifuentes, C Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2325_09

Cite As:
Muñoz, A & Cifuentes, C 2023, 'Case study: use of rebars with microalloyed steels in tunnels with induced seismicity', in J Wesseloo (ed.), Ground Support 2023: Proceedings of the 10th International Conference on Ground Support in Mining, Australian Centre for Geomechanics, Perth, pp. 141-150, https://doi.org/10.36487/ACG_repo/2325_09



Abstract:
The planned El Teniente mine conveyor tunnel has a length of over 9 km, going from the underground mine to the surface and is currently being developed with four active advance faces: from the surface, from inside the mine, and two faces with access through the construction decline facility called P4600. The conveyor tunnel will be used to extract all the production of El Teniente mine and therefore has a strategic role for the corporation. In early February 2023, a high-magnitude induced seismic event was recorded near the face of the Correa tunnel. Due to its energy and magnitude characteristics, this seismic event is the highest recorded in the El Teniente project’s tunnels and developments. Due to the high induced seismic activity experienced in this tunnel in recent years, the El Teniente division has implemented a ground support design focused on improving the interaction between the support elements that make up the support system. The aim is to enable the system to dissipate energy, deform, and maintain the stability of the tunnel during large seismic events. In particular, the retention capacity has been increased, and reinforcement bars with microalloyed steels have been used to enhance the probability of the bolt achieving the desired behaviour; that is, a ductile behaviour that fully develops its toughness.

Keywords: ground support, El Teniente mine, dissipate energy, ground control

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