Authors: Dunn, MJ


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Dunn, MJ 2015, 'How reliable are your design inputs?', in Y Potvin (ed.), Design Methods 2015: Proceedings of the International Seminar on Design Methods in Underground Mining, Australian Centre for Geomechanics, Perth, pp. 367-381,

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A variety of methods are used in underground design, including empirical, observational, analytical and numerical modelling. All design methods require inputs, and these are based on data obtained from core logging, mapping, laboratory testing, field observations and monitoring. This data then has to be compiled and interpreted so that meaningful and reliable design inputs can be derived. Design inputs are required to a have reliability and confidence level that is commensurate with the level of design (scoping through to operational) and that will ultimately satisfy the design reliability and acceptable risk profile for the design. To obtain reliable design inputs, data of sufficient quantity and quality has to be collected and analysed. The variability of this data has to be understood so that reliable inputs can be derived. Currently, very little quantitative guidance exists in the literature on assessing the reliability and confidence of geotechnical studies and design, although there have been attempts by various authors (Haile 2004; Haines et al. 2006; Read & Stacey 2009; Dunn et al. 2011) to qualitatively describe what level of geotechnical data is required. Recently, a number of authors have outlined methods that could be applied to assess the reliability of geotechnical data. These methods have been discussed, and the application of some methods has been demonstrated on data from underground feasibility studies to assess the reliability of design inputs. A preliminary rating scheme to assess the reliability of geotechnical models and design inputs has been proposed.

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