Application of the observational method in geotechnical safety management / Die Umsetzung der Beobachtungsmethode im Rahmen des Geotechnischen Sicherheitsmanagements

The uncertainties in the ground model and the subsequent design of tunnels call for an observational approach. To enable the safe and economical tunnelling of underground infrastructure projects with shallow overburden, a safety management plan has to be implemented. The successful application of the observational method is based on a comprehensive definition of the expected behaviour by the designer and the verification of the actual conditions by the site geotechnical engineer during construction. Advanced tools and methods for monitoring data evaluation assist in the continuous interpretation of the system behaviour, enable timely detection of deviations and check against the warning and alarm criteria. The paper shows the application of the observational method as defined in Eurocode 7 as part of a Safety Management Plan through two case histories from OeBB tunnel projects.