years of geotechnical engineering feedback in underground caverns

There is still an important gap between the quite empirical design methodologies based on lessons learned by companies from their own experience and, as one example of codified approach, the Observational Design defined by Eurocode 7 as one possible mean for Geotechnical Design (D’Allagnat, 2005). A consistent design for rock caverns still mixes numerical models, empirical/comparative approaches and validation through monitoring. A comparison between Figure 1 (Bieniawsky 1987) and Figure 2 (1st Draft from ISRM Rock Engineering Design Methodology Commission 2009), highlights that the main evolution is due to new tools and new formalism being available.