Integration of reflection seismic data into the documentation during the construction of the Brenner Base Tunnel

Abstract

AbstractThe 64 km long Brenner Base Tunnel will be the longest railway tunnel in the world when complete. As part of this mega project, an exploratory tunnel is currently under construction with a tunnel boring machine (∅ 8 m). Even though a geological model along the tunnel route was generated beforehand from the results of geological field mapping and deep drilling campaigns from the surface, some uncertainties persist due to the high overburden of up to 1,300 m. In particular, several fault systems intersect the tunnel route, but their position and orientation is uncertain. The excavation work is being documented with geological and geotechnical data, continuously updating the current geological model. Continuous seismic prediction measurements are integrated into this revision process. The aim is the detection, location and characterization of (sub‐)perpendicular to (sub‐)parallel fault zones ahead and to the side of the tunnel, based on the principle of body wave propagation. In a case study of a seismic campaign, the smooth integration of the acquisition into the regular advance is presented and the obtained 3D seismic models are compared to the geological documentation of the site geologists. It will be shown how the seismic analysis gives an added value for the advance and how it benefits the geological forecast for the forthcoming main tunnels.