When it comes to tunnelling, no one can fool Prof. Fritz Grübl in a hurry. "Even as a youngster, I was fascinated by construction sites with their large machines and tunnelling," says the 65-year-old civil engineering luminary. We take the retirement of the Munich-born professor as an opportunity to look back with him on his most memorable experiences in tunnel construction and at the university.
Michaela Leipersberger-Linder: Your fascination with tunnelling began at a very early age, your father was also active in this field. Like father, like son?
Fritz Grübl: It wasn't quite that simple. My father worked in the subway department of the city of Munich as a roadway construction manager and took me along to large construction sites as a youngster, which fascinated me very much with their many large pieces of equipment, the tunnelling and the whole shebang. During my civil engineering studies, I came to tunnel construction more or less by chance as a working student.
You can look back on a long experience in tunnel construction. Which technical developments have particularly stuck in your memory?
It was mainly the development of tunnel boring machines. My first construction site was already a machine tunnel. But then everything was still very simple, no computer in the machine, everything with manual control. Nowadays the machines are largely automated, the control stations look more like an airplane cockpit.
You have been managing partner at PSP Tunnelling Engineers GmbH since 1989 and Professor of Tunnelling and Engineering Geology at Stuttgart University of Applied Sciences since the summer semester of 2001. Do you know what boredom feels like?
Whether I'm studying, working on construction sites, in the office or at the university: I really don't know what boredom feels like.
How have you managed this workload over the years, which you have partly chosen voluntarily, such as your professorship?
I have managed it sometimes more, sometimes less well. But it's probably the case that the family as a whole has taken a bit of a backseat.
Why did you apply for a professorship at the university?
My predecessor, Professor Baudendistel, approached me directly and asked me if I would like to be his successor. I mentioned that I didn't have a doctorate and that I lived in Munich, but he just replied: It doesn't matter. And since my two office partners at the time also agreed, I applied for the professorship and - and I say this quite openly - never regretted it. The transfer of knowledge is still very close to my heart today.
You have been on the road in many countries and cities for tunnel construction projects. How have these diverse experiences influenced your professional career and personal development?
My first boss sent me to Syria for six months right after I started in the office - first to support construction management, and later I took over construction management there. I had never worked abroad before. Syria was a very military country, very restrictive. Of course, I had problems asserting myself as a young engineer, especially during my time as construction manager. But with the many stays abroad that followed, I learned to be more patient and not to lash out straight away, but to be considerate of other cultures, other attitudes and ways of working. These experiences have made me more relaxed.
So you have grown with your tasks?
Absolutely. You never stop learning. I'm often on the road as a tunnel construction expert and I can say that every construction site is different. You are always confronted with new things and have to make decisions - hopefully the right decisions. I am still learning every day. That is also my advice to students: Lifelong learning is very important, there is no other way.
What were the most impressive moments for you in tunnel construction?
It's always a really big event when a tunnel boring machine arrives at its destination and blows through. When the machine works its way through the target wall and then it falls down, that's a great feeling. And when you've been part of the planning and the tunnel looks good too, those moments are all the more wonderful.
You build tunnels of all kinds, railway tunnels, motorway tunnels ...?
Yes, all kinds of tunnels, even those that you don't think of directly, such as a Munich sewer that is more than five kilometers long. This can be walked through and navigated, for example with a rubber dinghy. Or think of electricity cable tunnels or district heating tunnels. The work in tunnel construction is quite diverse, even if it is only a small area of civil engineering.
Is there a tunnel you've been involved in that you drive through by car or, for all I care, by rubber dinghy, and you say "Mei, it turned out really nice?"
Yes, we planned the Farchanter Tunnel near Garmisch and did the construction supervision on the Oberau Tunnel. I think these two motorway tunnels have turned out very beautifully.
Nature and tunnel construction belong closely together. Only recently an accident occurred in Stuttgart. Flood water entered a tunnel, a scaffold was torn away, and one person was killed. Have there also been dramatic moments during your professional career?
Unfortunately, yes. A good 20 years ago I was a tunnel construction expert on a large motorway tunnel project in Holland, the Westerschelde Tunnel. The tunnel was being bored with a large tunnel boring machine with a diameter of 12 metres, completely modern, everything was going well. And then a small mistake caused a flood. In a matter of seconds, the groundwater shot into the tunnel at five bar. We got soaking wet and sprinted towards the tunnel exit because the water level in the machine rose very quickly. Fortunately the problem solved itself, but we were very glad that we had already left the tunnel at that point.
St. Barbara's Day is celebrated at the beginning of December. Saint Barbara is the patron saint of miners and tunnel builders. In addition, tunnel sponsors are always sought for tunnel construction projects, i.e. women who take over the sponsorship of the project during the construction phase. Why do you think only women are chosen for this, and what is the general situation with women in tunnel construction?
Saint Barbara is the patron saint of miners, in artillery and in tunnel construction. Why does it have to be a woman? Because the representative of Saint Barbara on earth should be female. And to the second part of your question, when I started in tunneling, there were no women in that line of work. When the first female engineer from Deutsche Bahn entered a tunnel, all the men ran out. They say that Saint Barbara doesn't tolerate any woman next to her in the tunnel. Meanwhile, more and more women are working in tunnel construction. The proportion of women in our master's programme in geotechnical engineering and tunnelling is sometimes over 30 percent.
In the summer semester of 2005, you and two fellow professors launched the Master's course in foundation engineering/tunnelling, which is now called geotechnical engineering/tunnelling. What prompted you to support this Master's programme?
In 2005, the Diplom courses were transferred to the Bachelor-Master system. In the course of this, we also considered which Master's courses could be offered in civil engineering. At the same time, the planning approval process for Stuttgart 21 was underway, with plans for tunnels more than 100 kilometres long. We were sure that well-trained, specialised civil engineers would be needed for such projects in the future and therefore launched the Master's programme, followed shortly afterwards by the Master's programme in Structural Engineering.
What is your best memory of your time at the university?
I always liked it when I noticed the students' great interest in geology and tunnelling during lectures, when questions came up, when the students participated and got involved. But it was just as nice to work with my colleagues. There is no competitiveness at the university, at least among the civil engineers. Everyone helps everyone. But also the big excursions were always highlights. In addition to the great destinations, there was time to talk intensively and more personally with the students, about private things, about life goals.
Your hobbies are mountain hiking, ski touring and sailing. Does that mean you also like to take on the elements in your private life?
Yes. I did swimming as a competitive sport for a long time, hence my love of sports. I also live in Munich, so the mountains are close by. From here you can reach the most beautiful mountains in an hour and go on hikes or ski tours. The love for sailing was already passed on to me by my parents. And when you're always working underground, you want to get out into the fresh air.
You have been married to your wife, who is French, since 1982. You have two daughters, twins, born in 1984. How have you managed to reconcile family and career?
FG: I would say that I have managed it reasonably well. We have a very good relationship with our children and grandchildren. But it's a touchy subject. If you ask my wife, the answer would probably be a little different.
Your love, besides your family, is the South of France and a big sailboat waiting for you there. How will you spend your retirement?
We are looking forward to our boat, with which we would also like to go on longer trips. But I still have other things to do: My daughter Véronique and her husband have bought a terraced house in Munich, and there's a lot of renovation to be done.
But that doesn't have to be tunneled, does it?
(Laughs) No, of course not. But I'm quite handy, and there's a lot of work waiting for me there. But above all I'm looking forward to more spontaneity during the week, for example when a friend asks if I'd like to join a skiing or hiking tour. But I'll still be working a bit too. I've been commissioned as a tunnel construction expert for the second main line in Munich, a very large project that will also be running for a while.
I've heard that the university needs you for a while, too? Wait, I phrased that wrong: The university definitely needs it! But you are willing to give some of your time in the future as well?
Yes, I will remain at the university as a lecturer.
Your two grandchildren - Max, aged four, and Louisa, she is three - are very important to you. Imagine you are on the beach with them in the south of France. The two of them have built a huge sand castle that they want to tunnel under, but the building keeps collapsing. The two of them are on the verge of tears. What advice do you give them?
Don't give up! Keep trying again and again, eventually it will work out. And if it doesn't, I'd do it myself. If the tunnel collapses again, I'm sure they'll be very happy!
