Meeting The Challenges Of Complex Excavation Interactions

Design of buildings on and around existing underground infrastructure is becoming more and more necessary as land within the Sydney CBD and surrounds becomes a greater commodity and below ground space is being further utilised. In mining, many underground mines need to go deeper to be economically feasible, experiencing higher stresses and challenging conditions than ever experienced before in addition to complex geological settings with significant three-dimensional effects and multiple mining fronts. As a result, such complex and dynamic environment poses significant geomechanical challenges for the planning and design of such projects. The successful design of such projects is therefore fully dependent on a good understanding of what generates the complexity and the consequent impacts. Forecasting and predictive analyses are typically not needed for investigating such complexity and targeting cost-effective, sustainable and resilient solutions. Such analyses often involve large scale and complex 3D models that should be combined with experience based design and understanding of the fundamentals. This paper presents some discussions on how to address complexity with 3D modelling and present some modelling techniques that are useful to achieve reasonable results. Examples of model confirmation are also given to illustrate how some degree of confidence is gained based on available monitoring data and/or observations combined with local experience.