Geotechnics and mass balance of the earthworks for the second tube of the Tauern Tunnel / Geotechnik und Massenbilanz der Erdbauprojekte der zweiten Röhre Tauerntunnel

The construction of the 6,545 m long second tube of the Tauern Tunnel required a well thought-out concept for the disposal and reuse of the material excavated from the tunnel. Because the reuse of the excavated material had been assigned the highest priority for saving resources according to the Waste Management Law (AWG), the project also included a number of officially approved earthworks projects. This article gives an overview of the considerations and challenges, which arose during the design and construction phases with regard to the disposal and reuse of this material. Particular attention is paid to embankment filling to raise the level of the Tauernalm service area, where about 235,000 m³ of tunnel spoil was filled in only three months. The article also describes the particular challenges of geotechnical design, supervision and logistics on this project, and also the overall mass balance of the tunnel excavation, which had to be adapted a number of times during the construction phase due to altered project parameters and had to be considered as a direct interaction with the tunnelling concept.