Characterizing parameter and model uncertainty in rock engineering

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Recent years have seen considerable advances in both numerical methods for rock engineering design and techniques for acquiring data on rock masses. The demands placed on both geomechanical models and data collection methods continue to increase as population growth extends into high mountain areas and large open pits reach depths of over 1km. Underground mines and tunnels increasingly have to be excavated at greater depths and in more complex geological and rock mass environments. In challenging economic times the engineer is required to optimize economic development with increased due diligence in terms of associated risk. Notwithstanding the enormous developments in our simulation and data collection capabilities we are still all too frequently faced with safety and economic problems due to unexpected rock slope and mine failures; a recent example in Canada was the 2008 Porteau Cove rock slope failure which closed the Sea to Sky highway, the route to the 2010 Olympics at Whistler. A fundamental task faced in design and analysis in rock engineering is associated with the implications of both parameter and model uncertainty. This research endeavours to develop new methodologies for characterizing parameter and model uncertainty in rock engineering. An integrated rock mass characterization-numerical modelling approach will use state-of-the-art techniques to characterize rock masses in varied underground and surface environments. The implications of uncertainty in input data for numerical modelling of failure mechanisms in rock will be explored using a toolbox of numerical methods. The influence of the model uncertainty will be investigated using a spectrum of continuum, discontinuum and hybrid codes ranging in complexity from simple 2D to 3D analyses. An emphasis on brittle fracture modelling will explore the implications of uncertainty on discrete fracture networks and subsequent synthetic rock mass approaches. The proposed research will endeavour to apply a suite of uncertainty analysis tools to rock engineering problems and demonstrate the importance of this approach toward achieving increased confidence in rock engineering design.