CLAUDIO CABRAL DIAS | INTERVIEW


part but I still need to see the works being actually materialised: you design something and in one or two years you know you are going to see it actually on the ground.” And what, in his current lectures and in


any future teaching career, are his priorities for students to learn – the fundamentals of tunnelling that they dare not lose sight of?


“First, I try to get them to think for


themselves, because a lot of people coming to my course want to be given rules of thumb. They ask: ‘What should we do in such-and-such a case?’ And then you explain that it depends, because every tunnel and every tunnelling project is different so there are really no rules that you can apply to all of them. So you yourself have to think and work out what is the best way, what the alternatives are, and why this one or that one will be better. “And there is no one right answer.


Different countries have different methodologies, different experiences, different methods and means. “And the second thing I try to tell them


is not be scared of doing things in 3D. Nowadays more and more people use 3D models. Even a few years ago they used to be time-consuming and difficult to populate but now they are becoming user- friendly so they are easy to follow up. Of course, younger people have less difficulty with this because they have been digital since they were born; for older ones, old habits are difficult to change. “And a third thing is to be more


collaborative: work more with people with different specialities. The architect, the mechanical engineer, the geotechnical


I THINK THIS IS ONE OF THE BEAUTIES OF THESE MAJOR INFRASTRUCTURE PROJECTS. YOU ARE ABLE TO BE CONNECTED


person - sometimes there is still the kind of feeling, ‘Oh, we know that architects do it that way, but we tunnel engineers do it this way; we have done our part correctly so if there is an issue it’s not our problem and we can blame the mechanical engineer or the designer or the architect or whoever when it goes wrong.’ But it is all one project and all these aspects have to work together and it is the interests of everyone to get the best outcome for it. “So I try to encourage more


understanding. I always advise in those courses to not stick just to the discipline you know. We know about tunnelling, we know about civil engineering, but if possible try to participate in meetings even of the electrical guys, the logistics guys, the designers, all of the others. You may not know enough to contribute but, even if you say nothing, just by listening you will understand better why those people are actually requesting something; or, even if you are not able to help or change something on that project it may be that in the next project you will be able to be a bit more collaborative and helpful toward the other disciplines. “It goes back to what I was saying about


the designer actually being on the site, working there with the contractor, seeing the problems, and understanding that particular project and piece of ground. “But I think this collaboration is


increasingly part of the way that we work nowadays. BIM methodology means that


we have a shared model that everyone has access to and where everyone is working in the same environment. I think that aligns very well with this perspective. It is something that in my - shall we say, short - career I have been able to see. When I started in Brazil everything was more compartmentalised. You would get your part of the design, and add your contribution to it, and then send it to the client, not really knowing maybe what they were actually going to build. If it is an electricity tunnel, as the Ipswich one, you might not know if the cables are to go on this side or that side, or towards the top or the bottom. You might be told that there are going to be some more concentrated loads around this part, but you wouldn’t know the details. “Nowadays we work in a more integrated


way and you actually see what is going on inside the models. That’s a more holistic and complete way of working on projects, and it will continue to grow as time goes on and everyone is more connected digitally. “I think this is one of the beauties of these


major infrastructure projects. You are able to be connected. I can be here, in Madrid, and also working with teams from Australia and from India and sharing their experience. In the tunnelling industry we depend a lot on those sorts of skills, and the training and experience that comes from shared working on job after job to get to that level of expertise.”


SPOTLIGHT ON SUSTAINABILITY “Sustainability is a big concern: I think everyone in the civil engineering industry is worried, especially about the concrete we use,


and in particular because of its cement. “Cement is one of the main polluters worldwide; it is hugely energy intensive to produce. But at the same time it is quite a durable


material, so if we design it well we can have structures that can last 200 years and much longer. “So the issue is how to produce a more sustainable concrete. I see methods already consolidated to replace part of the cement with some byproducts of other industries, like Ground Granulated Blast-Furnace Slag (GGBS), and things like that. Even glass or plastic have been suggested. I think plastic is going to be difficult but there are byproducts of other industries that could be used. “We replace a lot of rebar by steel fibres or microfibres that produce less carbon. These are the main fields but I think that, to be honest, a holistic, moralistic approach is necessary: it is not just the concrete itself but the entire process. “For instance, using more numerical and 3D analysis is also a way of making the design more efficient, because you can analyse


a structure’s behaviour more realistically. Materials play their part; so also do contractors using more efficient equipment and building in a more efficient way. “So, I think the boundaries are always moving. Every year we push a bit. Some years we may be transforming materials really fast,


maybe other years it is standards that move, or designs. I think everyone is concerned but one must not think that changing just one thing will solve the problem. Everyone is doing their part and improving.”


September 2024


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