Tunnel and underground construction would not be possible without construction machinery. In confined spaces, these often highly specialized machines must carry out a closely coordinated sequence of...

Every year, millions of tonnes of excavated material are generated during tunnelling and underground construction projects. To date, most of this material has been disposed of in landfill sites without further use. The interdisciplinary research project Geo-BAB is investigating how such clay mineral-rich materials can be transformed into a low-CO ₂ alternative to conventional cement through thermal treatment and chemical activation.

Science meets mechanical engineering, theory meets practice, and academia meets industry. And Zurich meets Schwanau. Georgios Anagnostou and Martin Herrenknecht have a good reason to meet: A joint study by ETH Zurich and Herrenknecht AG on the feasibility of a tunnel under the Strait of Gibraltar has been finalised and concludes that this long-cherished dream is now technically feasible. A conversation among experts.

The Holzminde is a small river that flows through the center of the town of Holzminden in southern Lower Saxony, Germany. The town’s proximity to the “red water”, as the Holzminde is popularly referred to, has shaped its development over the centuries – and in 1904, one section of the river was diverted into a tunnel structure. This made it possible to create enough space for new traffic routes in the town center. The result was the construction of what is now the state highway L550. More than a century later, the historic tunnel is once again the focus of an important infrastructure project: over the years, time had left its mark.