Using the example of the Boßler Tunnel, the importance of careful rock mechanical investigations for the excavation concept of a tunnel is shown. The preliminary exploration revealed that squeezing rock conditions were to be expected in the middle section of the tunnel. In another tunnel section, karstification had to be expected. Towards this background, the tunnel was tendered for construction with conventional means (“shotcrete method”). Along the first 2.8 km, the use of a TBM was permitted. By driving an exploration shaft and gallery combined with accompanying rock mechanical investigations and numerical calculations, it was possible to create the basis for allowing for a TBM-excavation in the entire formation of the Brown Jurassic. In addition, the program for karst exploration was adapted to the requirements of a TBM heading.

The fourth tunnel drive of the tunnel boring machine (TBM) „SUSE“ started in November 2018. Before that, the 120 m long machine had to be dismantled into seven pieces, which then were turned one by one underground. This article contains a short video clip of the unusual turning manoeuvre, made by the DB Projekt Stuttgart–Ulm GmbH.

The 3rd Forum on Injection Technology, which attracted 220 participants on November 21 and 22, 2018 in Cologne was a huge success – involving a series of lectures as well as networking and a get-together for the industry. On both days of the Forum at the Maternushaus, a lively exchange of views among experts took place, in the lecture hall, at the exhibitions staged by the sponsor companies as well as at the grand gala evening held for all those taking part. The article also features a short film of the "Forum Injektionstechnik 2018" (the interviews are available in German language only).

The fourth ITA Tunnelling Awards was organized together with the CTUC conference in Chuzhou, China, on 7 November 2018. „The ITA Tunnelling Awards 2018 is a unique conference, focussing on and sharing the yearly major achievements in our tunnelling industry, including the remarkable projects, technical innovations, innovative underground space concepts and safety initiatives as well as excellent young tunnellers and lifetime achievement“, Jenny Jinxiu Yan, ITA Vice president and chair of the ITA Tunnelling Awards 2018 Committee, welcomed the audience waiting for the announcement of the Award winners.

From May 3–9, 2019, the World Tunnel Congress will take place in the South-Italian city of Naples. On May 9, the final day of the congress, participants will have the opportunity of joining technical visits to underground construction sites and can choose one of four interesting destinations ...

The complicated geology presents a challenge to man and machine for the new Stuttgart-Feuerbach rail tunnel, part of the major project Stuttgart 21. Owing to the rock that contains anhydrite, holes for excavation and injections must largely be carried out by the dry drilling method. As a result, modified tunnelling jumbos and vehicles with suction aggregates are deployed. The excavation is partially secured by pipe umbrellas.

Tough working conditions prevail in tunnelling. The demands posed on technical equipment are correspondingly high, as e.g. gears, which must reliably cater for movement in various machines. In tunnel boring machines (TBMs) planetary gears must withstand strong vibrations, impacts, high temperatures and pronounced external pressure. These powerful gears are also applied in building cranes, drilling rigs, cutters, excavators, pumps or tracked vehicles.