Excavator-mounted cutting attachments have become established in tunnel projects of the Austrian construction group Porr and in other construction companies. The wide range of applications is carried out with both standard and special cutters. In some cases, even excavation of the tunnel is carried out using cutting technology. In soft rock, this offers an advantage over blasting, because the bedrock is not damaged by vibrations. Moreover, numerous other operations in tunnel construction and rehabilitation are made possible by excavator-mounted cutting attachments.

Sprayed concrete construction in double-shell lining is a CO2-intensive construction method for tunnel structures. This article explains the ecological impact of concrete in underground construction and provides options for using this material responsibly and in a climate-friendly way – particularly in terms of planning and concrete technology.

To realize the integrated synchronized timetables in long-distance traffic and to increase the capacity in freight traffic between Brig and Bern, the two-lane extension of the Lötschberg Base Tunnel (LBT) is necessary. This demands the installation of an inner lining over 14 km in the second LBT tube. Considering the excavation profile available, a skillful choice in the sequence of formwork carriage geometries (FCGs) can lead to optimization of the concrete volume to be installed, the feasibility of the build and the construction sequences. In the sense of a “proof of concept”, mathematical optimization algorithms are used to find a cost-optimal sequence of FCGs for a defined tunnel section. The article in tunnel 5/2021 describes the chosen approach and the results of the cost optimization.

As part of the STUVA Conference 2021, the STUVA Expo will take place on 24 and 25 November in Hall 1 of Messe Karlsruhe in Germany. With more than 200 exhibitors, STUVA Expo is one of the largest trade fairs for service providers and manufacturers from the tunnelling industry. Our trade journal tunnel presents company information, services and new products from a number of exhibiting companies at this year's STUVA Expo.