Innovative engineering approach to the stabilisation of rock masses in high stress conditions

CIM Montreal 2011
Francois Charette, Charlie C. Li,
Abstract Abstract

High stresses conditions in weak rock masses lead to large deformation and breakdown of the rock material, while stress release events in hard rock mines can lead to sudden and usually violent rock failure. Typical support system combine different reinforcement and support mechanisms to provide the required convergence control and retainement, but results are often mitigated by failure of surface liners, shotcrete and tendons. As well, different types of stress release events lead to different rock failure mechanisms and the support system need to be adapted to the type of event. The goal to help the rock to support itself is often not achieved successfully and stability is reached only with rehabilitation of the excavations. The paper discusses different requirements of support and reinforcement for different failure types, and assess the properties of the system that can provide stability to the excavation. Also discussed is a renewed approach to the basic principles of ground control and analyses the advantages of using a more compliant reinforcement. In addition, the mechanical performance of a new reinforcing tendon is presented and analysed in view of the field requirements. Field tests results are presented.
Keywords: weak rock, Rock support, Rock bolt, dynamic conditions
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