New construction of Albula Tunnel II – Experience with steel fibre shotcrete

Abstract

The new construction of the 5860 m long Albula Tunnel was mainly carried out by blasting from the Preda and Spinas portals. Due to the exposed location in the high mountains, mixing plants were installed on both portal sides for the concrete supply; the concrete aggregate was largely produced from the excavated material, with a gravel plant being built in Preda for this purpose. The planned tunnel lining provides for a single‐shell shotcrete construction for the most part. In the course of the excavation work, the excavation support was optimised so that the reinforcement mesh in the main support class in the single‐shell area were replaced by steel fibre shotcrete.