Building and excavating in the underground environment naturally results in changes in the stresses. Induced stresses can concentrate in sensitive areas leading to rock falls and high deformation. As construction proceeds to deeper levels, or as multiple excavations are created in the same area stresses accumulate and can overcome the strength of the geology hosting the excavations.

Specifically, problems can be encountered when excavating through geologies with highly varied properties. Stresses in these areas are concentrated not only under the effect of multiple different excavations, but by the natural capabilities of the different geologies to withstand and/or transmit that stress. It is a situation in which analytical and/or empirical methods are insufficient, and numerical methods can produce inaccurate or non-verifiable results. Improvements in modelling methodology are required to enable the numerical tool to be of greater help to design in these situations where it is potentially unsafe, and certainly inefficient, to design based solely on “what was done before”.

To better design openings and support systems in these areas, it is necessary to better understand how excavation-induced stresses and geologically driven stress concentrations interact to create rock failure. This project addresses this problem by using a combination of data collection in a controlled environment, and numerical modelling of complex, multi-opening excavations in order develop a method for improving design and support systems.

The research generated significant amount of data which can be used for further research and has already been assessed in the daily mine operations and planning.