Tunneling in Alpine Fault Zones – Case Study Semmering Base Tunnel

Tunneling through Alpine fault zones, characterized by high in-situ stress and potential for substantial ground deformations, requires innovative excavation and support strategies. A novel yielding element, the HS-EPS, made of lightweight high-strength expanded polystyrene, has been successfully implemented to address these challenges at the Semmering Base Tunnel in Austria. This modular system allows for on-site adaptation to deformation patterns and changing ground conditions, offering a cost-efficient alternative with higher support resistance than traditional steel sets. The study highlights that radial deformations due to rock pressure are effectively transformed into tangential closure of the ductile lining, ensuring controlled deformations without overstressing the shotcrete during its early curing phase.

Wannenmacher, H., Entfellner, M., Fiest, T., & Schubert, W. (2024). Tunneling in Alpine Fault Zones – Case Study Semmering Base Tunnel. 58th U.S. Rock Mechanics/Geomechanics Symposium. https://doi.org/10.56952/arma-2024-1193