Tunnel excavation failures and unforeseen ground conditions

This paper focuses on the evaluation by forensic geotechnical engineers of unforeseen ground conditions in a tunnel excavation and the contractual consequences. A case study is presented of a water transfer tunnel built in Italy at the beginning of the 1990s. A sizeable pressurised aquifer was discovered at the tunnel entrance, which ultimately resulted in the contract being terminated. The aim of this paper is to examine further the geological-geotechnical conclusions of the case study, with a view to relating them to the legal and contractual evaluations and, consequently, to the field of forensic engineering.