The Tunnel Oberau, with a length of 2.9 km, forms the core of the local bypass of Oberau. Between the two massifs Kirchbichl and Mühlberg, the tunnel is situated in the valley of the Gießenbach in alluvial gravel with only a small overlap underneath settlement-sensitive buildings. In this paper, the measures in the tunnel to minimize the settlements of the buildings during the shotcrete excavations are described. Basis for this planning were extensive 3D-FE-calculations. Furthermore, under two buildings a compensation grouting measure was carried out, in order to compensate the occurring settlements. This paper describes how the required time and the amount of injection material (grout) could be reduced during the compensation grouting in highly permeable gravel. 

[1]       Fillibeck, J. 2012. “Prognose von Setzungen beim Lockergesteinsvortrieb – Empirische und numerische Verfahren.” Habilitation Thesis, Center for Geotechnics TU Munich.

[2]       Fillibeck, J., Klinger, A. 2017. “Shotcrete Excavations in Cohesionless Soils – Comparison of Different Methods for the Reduction of Settlements.” Proceedings of the World Tunnel Congress 2017 – Surface Challenges – Underground Solutions, Bergen 2017.

[3]       Fillibeck, J., Klinger, A., Geuder, S., Willberg, U. 2017. “Geotechnische Herausforderungen beim Bau des Tunnels Oberau.“ 22. Symposium Felsmechanik und Tunnelbau, Fachsektionstage Geotechnik der DGGT, Würzburg 2017.

[4]       Schikora, K., Thomée, B. 2006. “Bemessung von Tunnelaußenschalen in Spritzbetonbauweise unter Berücksichtigung von physikalisch nichtlinearem Materialverhalten mit besonderen Hinweisen auf die neue DIN 1045-1.“ Spritzbeton - Technologie 2006, Institut für Betonbau, Baustoffe und Bauphysik, Universität Innsbruck, 147-56.