Herrenknecht: Innovative Tunnel Construction for Global Infrastructure

Messe.TV presenter Jürgen Groh in conversation with Achim Kühn from Herrenknecht at InnoTrans 2016 in Berlin. As a result of the trend that rail and metro in cities is becoming an increasingly important topic, the manufacturer of tunnel boring machines is benefiting from a boom in tunnel construction that has been going on for years. More and larger projects are being planned and realized. As a tunnel specialist, Herrenknecht has a high level of expertise and is constantly researching improvements.

Metro and railway solutions - tunnel construction from Herrenknecht

Achim Kühn: The trends are very clear. Metro and railways are developing extremely well in cities around the world. We can speak of a "golden age" in tunnel construction - never before have so many tunnels and such ambitious tunnel projects been carried out in the world. Herrenknecht manufactures specific tunnel boring machines - all of which are unique - according to project requirements. We also help ambitious clients and construction companies to build these tunnels quickly, on time and within budget. Jürgen Groh: Which regions of the world are currently the most attractive for expansion? Asia - Europe? Achim Kühn: Asia is a good keyword. Asia-Pacific is a very interesting market for us - especially China, where we have completed more than 600 projects in the last 10 years. The Middle East is very strong and we have invested heavily in metro systems there. South America is also a very interesting market for Herrenknecht. In the last two years, there has also been a significant boost to the business from Europe. Major routes such as the Gotthard Tunnel were built with tunnel boring machines from Herrenknecht. The project was opened 1 year earlier than planned because machine technology can also be used to implement such large projects well and safely.

Urban infrastructure: Crossrail London

Jürgen Groh: What I still have in the back of my mind is the Crossrail project in London. Achim Kühn: Crossrail had its final breakthroughs in 2015. This was the largest construction project in Europe and is nearing completion. In this project, two tunnel tubes were built from west to east through the middle of the city within three years in order to improve the infrastructure situation for London and the surrounding area. Jürgen Groh: When you talk about building tunnels, the model on your stand here immediately springs to mind. Achim Kühn: Exactly. That's the front part of a tunnel boring machine, that's the actual boring unit. In London, it was a machine that crossed under the Thames. Jürgen Groh: Why is the arrangement in the construction of the drilling unit exactly as shown here? For my understanding as a layman. Achim Kühn: It is arranged in such a way that the clayey soil in London can be excavated cleanly. One issue is to avoid sticking in the middle of the drilling unit. The cutting wheel is designed according to the soil conditions. The teeth peel out the soil, if stones appear they are broken up and crushed by the cutting edges and can then be removed to the rear using a fluid system. Jürgen Groh: What is the diameter of this pipe? Achim Kühn: The diameter for the Crossrail project in London is 7 meters. The largest tunnel boring machines that Herrenknecht has ever built had a diameter of almost 18 meters - that makes us the world record holder. The principle is as follows. When we are in soft ground, we have a shielded tunnel boring machine. This model is surrounded by a steel cylinder that protects the machine and the front unit from the surrounding soil. Behind this, the tunnel tube is created ring by ring. The ring consists of individual segments that are offset, bolted and sealed with an erector. Once a ring is securely installed, the next drilling stroke can take place. Behind this actual drill shield, there is then a back-up system of between 120 and 400 meters, which provides all the logistical units needed to supply the machine in a stable manner. The back-up system is also required for the entire construction process in order to get materials or vehicles in and out.

Metrotunnel project in Doha for Qatar Rail

Jürgen Groh: How much "human power" is required in a process like this? Achim Kühn: You usually need around 20 good people to operate a machine like this. Our offer always includes electricians and hydraulic engineers to ensure that the system runs very stably. In 2010, Qatar Rail decided to carry out the first expansion phase for the Metrotunnel project in Doha and we were then confronted with this project in 2013. It was about supplying 21 tunnel boring machines for this city, because the plan was to build 112 kilometers of new tunnels in the city in just 26 months. At peak times, 20 machines were actually in use in Doha, which led to an entry in the Guinness Book of Records.

Jürgen Groh: Is it fair to say that "Made in Germany" is still in demand in this sector? Because you really do realize projects worldwide. Achim Kühn: In this case, the royal family, the state, really placed great value on German engineering and mechanical engineering. That really helped us to get involved in the project. Our clients were international joint ventures staffed by leading construction companies and they placed the orders with us. Jürgen Groh: Which countries are the biggest competitors in the tunnel construction sector? Achim Kühn: For many years, there were a few western brands. However, we are now seeing a strong rise in Chinese competitors. Jürgen Groh: Do you also have the problem that innovations and technical developments are being "copied"? Achim Kühn: It doesn't make any sense to categorize this as "technology transfer". It's a competition and the fastest and most innovative is the one that comes out on top. We are confident that we can hold our own. Jürgen Groh: Thank you very much, Mr. Kühn, and have a successful trade fair. Achim Kühn: Thank you very much Mr. Groh, goodbye.

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