An alternative view on geotechnical parameters for tunnel design in Sydney

Bertuzzi (2014) presented an update of the geotechnical design parameters previously proposed by Bertuzzi and Pells, (2002). The updated parameters focused on tunnel design with two sets of parameters introduced to cater for different design approaches dependent on the scale of the assessments. The proposed parameters provide a useful starting point and reference for practitioners working on tunnel design. However, Bertuzzi (2014) provides no guidance on the appropriate use in a model which may, in some cases, result in discrepancies between the two different design approaches and expected range of ground behaviour. This paper provides additional comments on the differences between the two design approaches and guidance on the use of updated design parameters. The objective is a compatible behaviour independent of design approach chosen. In addition, design parameters may vary dependent on different interpretations and new sets of parameters based on the discussions in this paper are suggested as an alternative reference.