SBT – Underground post‐excavation grouting

Abstract Grouting has become indispensable in modern tunnelling. Not only does it serve to improve rock mass integrity, but it also makes a significant contribution to groundwater protection amid growing sensitivity toward water resources. The decision regarding the choice of grouting system and the justification for its application requires careful consideration of technical, economic, and ecological factors. During the construction of the Semmering Base Tunnel (SBT), geological and geotechnical boundary conditions in several sections necessitated post‐excavation grouting measures. The following paper presents insights and experiences gained from the post‐excavation grouting on the SBT, illustrating the applied measures, the achieved results and the lessons learned in relation to the surrounding geology.