Eivind Grøv loves rock. As a building material it beats almost anything that mankind has managed to produce in the millennia that have passed since we first started living in cities back in Sumeria some eight thousand years ago. “There have always been caverns,” he says, “and people have always used them. Look at the Batu Caves in Kuala Lumpa in Malaysia. There is a huge rock cavern in limestone. It is used as a temple. It is a karst phenomenon, high and wide, and it is self-stable – when I did a visit it showed no need for shotcrete or wall support or concrete structures at all. It is just a beautiful cave, and very very big. It shows that nature is an ingenious engineer.”
And people have always tunnelled through rock mass.
“People have been building underground for two thousand years and more. Most breathtaking is the 5.5km-long tunnel through Mount Salviano that was conceived by Julius Caesar and carried out under the Emperor Claudius to drain Lake Fucino outside Rome. It has 33 vertical shafts.”
Many tunnels and caverns are lined, with concrete or brick or iron. Grøv prefers bare rock mass. That is possibly because he is Norwegian.
“It goes back to actually utilising different geologies as a construction material, with all their different capabilities and capacities and weaknesses; and that is actually what has been motivating me: that what we call the rock mass is a beautiful construction material. It is not an engineered material so we have to learn to know it and take this into account in the design.
“That is certainly true in Scandinavia where we have lovely hard rock; but there are lots of places which have the same type of beautiful rock mass that we have here so the possibility actually to utilise the rock as a construction material exists in many other places around the world.”
Not everywhere is so blessed. There are sandy places, and clayey places, and chalky or fractured or waterlogged places.
“Of course, it would be utterly wrong to try to implement something which works in Scandinavia in places where you’re working with sedimentary layers and loose rock or soft ground conditions. I have given presentations in a number of places around the world and always I make two statements: one, that we have such good rock mass in Norway; and, two, that the Norwegian Government is so rich from North Sea Oil that it can build whatever tunnels it would like with that money. Both statements are untrue.
“Because in tunnelling you have always the possibility to meet continuously changing conditions. You could be working with beautiful high quality rock mass, then you move forward one metre and find you are in a weaker zone. The fact that we are able to understand and take benefit from all the different capabilities that rock masses possess makes it possible for us to actually use this to make beautiful caverns and tunnels that are useful to society. And this is true not only for Norway but in lots of different places.”
Such as, just for example, those Kuala Lumpur caves.
“We have now the competence to build underground in almost all geologies,” he says, “and we have now a global concern and a global need to build underground, because space above ground is running out. The motto of the Norwegian Tunnelling Society is ‘Surface problems – Underground solutions.’ We need the above-ground spaces for people, and for nature and biodiversity and carbon-capturing forests and so on.
“And, in addition, the need of going underground today is also related to the fact – and I don’t like to bring it into the discussion but we have to acknowledge it – that there is a geopolitical situation today which is bringing about a very uncertain world. I am old enough to have lived through Soviet Premier Khrushchev banging his shoe on the desk in the United Nations.” [It happened in 1960]. “We grew up during the Cold War. Those times were in some sense predictable. What we see today is not predictable.
“The sad fact is that we have a situation that may force us to find solutions that let us protect ourselves and that secure for us sufficient stores of water and food and so on. We may need a refuge, for people and for supplies. The underground can provide these kind of things to us.”
Or if ecological disaster rather than war is the issue, it may be worth noting here the Global Seed Vault on the Arctic island of Spitsbergen (main island in the archipelago known as Svalbard), 1.3 million seed samples, collected together from almost every country, are stored in a tunnel dug into the permafrost. This is a ‘gene bank’, its purpose is to secure the foundation of our future food supply should existing, potentially vital, varieties of food crops be lost.
So railways, roads, hospitals, work places, spaces to generate and store power, and to provide refuge against disaster – all of these, he says, can be usefully placed underground. Homes, he says, should not be.
“I do not think that living underground should be the goal. It has been done in the past: in Libya, in Cappadocia in Turkyë and in other places, underground houses worked well for their people; and Petra is, of course, astonishing. But I think the goal of building underground would be that it enables us to free the surface for human beings.
“Probably it would be possible to live underground in apparent comfort. You can have artificial lights and circulating fresh air and all these kind of things that you need, but I think that we should prioritise the overground space for people. As a species we should be able to see the sky.”
Working underground, though, is something quite different.
“It is perfectly realistic that both whitecollar and blue-collar work would be in underground facilities in the future. We have quite a few already; new ones only need imagination. In Singapore an Underground Science City was proposed. Hospitals could be placed underground – one was suggested some time ago for the city of Mecca to serve the pilgrims. Fire stations could be underground; so could national archives – the Vatican has already done that. Garages and workshops, laboratories, testing facilities – one could even consider graveyards.” The sky is not the limit. “The fantasy is the limit,” he says. “This is where we should occupy ourselves.
So how did all this begin? Why did he decide to become a tunneller?
“I didn’t decide. When I was in college I wanted to have a job where I could be outdoors in nature, travelling, and not being always in an office. I was studying geology, so I became a geologist within the field of engineering geology, which seemed to tie those three things together.”
Born and raised in Drammen, just north of Oslo, from early in life he enjoyed cross-country skiing and soccer. But he also recalls the ‘Spiralen’ tunnel, located by the town. A spiral tunnel, it was originally excavated up through a hill to provide rock for landfill along a river and fjord. Afterward the tunnel became a tourist attraction, letting visitors proceed up the hill, travelling inside.
With no family working in his chosen field of geology and underground engineering, he reflects on Spiralen was maybe seeded “an interest or curiosity in tunnelling as a career.”
After mandatory military service, he pursued his academic studies in Trondheim, at the then renowned Norges Tekniske Høyskole (NTH), pursuing a focus on engineering geology. He graduated in 1983. NTH was formed in 1910 and would later, in the mid-1990s, become a core part of the Norwegian University of Science and Technology (NTNU). Later still and after much work on projects across the world, he would find himself teaching and supervising students back at NTNU, as an Adjunct Professor, over 2009-23, “at the same part of the Faculty where I used to be a student myself back in the day.”
Studying geology gave him his wish to travel and mostly work outside of an office. Over the following decades, he worked on a variety of underground projects.
“I have worked a lot abroad. My first experience was almost six years in Saudi Arabia in the ‘90s. That was interesting for many reasons, firstly because there was a totally different culture. Understanding and learning the culture is something which is absolutely mandatory for an engineer who is going abroad, so that was good experience; but it was also a project which was completely filled up with challenges for an engineering geologist. It really was years filled with learning from day one to the to the last day there.
“Connected with that was that in such a big project you are automatically building up your network – and this comes more or less for free. People I got to know thirty years ago in Saudi are still important members of my network.
“Since then I have worked in China, in South Korea, in Hong Kong, in Malta, in Chile, in Singapore, in Iceland – a lot of different places.”
With such experiences comes wider perspectives on possibilities for the use of underground space, as he discusses.
He says energy storage too, in his view, is something that can certainly be put underground – and which, in the transition from fossil fuels to renewables, is becoming ever more important. There is a ‘ladder of complexity’ in liquid and gas storage, he says. In this, as in other applications, the easy underground projects have already been done.
In Norway, and also elsewhere, they have used unlined tunnels in hydropower plants for headraces and air cushion chambers, and more; he says that these developments have taken place in unlined pressurised tunnels from a couple of hundred metres to a thousand metres.
“Air cushion chambers have been built unlined to pressures of up to 7.5 MPa. So Compressed Air Energy Storage (CAES) – in dedicated rock caverns, unlined and pressurised or chilled – would be easy to build. LPG storage in various combinations of pressure and temperature is similarly practicable. Storing ammonia in unlined caverns is partly within existing capabilities, though you would need to control temperature and pressure to obtain a maximum reduction in its volume. But it has been stored with success in hard rock caverns, and doing so is much less complicated than storing hydrogen.
“Hydrogen is widely promoted as a source of clean energy but storing it underground on the large scale requires very cold temperatures and is fully outside current technology. But it is an active field of research, and I would guess that within ten years we should be able to do that. LNG can be dealt with in steel-lined solutions, but to the extent that is possible unlined, or sprayed concrete-lined solutions are to be preferred.
“Pumped storage hydro is another solution that involves tunnelling, and one that is fully operational in some places.”
Can we store CO2 in dedicated manmade caverns?
“That is partly within existing capabilities; we have been looking at it and it is absolutely feasible. Temperatures in the range minus 55°C to minus 22°C and pressures between 7 bar and 18 bar are the requirements, and it would have to be cost-competitive. There are some challenges to overcome there – for example, how does CO2 interact with water, and with concrete?
“And underground solutions have a great potential to house the next generations of nuclear power production, though cost and public consensus would be issues here.
“We may have to build new caverns for such things, which takes energy of course, but even so the balance would still be advantageous. And there is the real possibility of re-purposing existing caverns. If we look at the big perspective you can perhaps reuse and convert an existing cavern to a new purpose. There is, in Norway, a research programme that we are trying to put together right now to look at future reuse and multiple-purpose use of rock caverns and tunnels and underground facilities to a much larger extent that we have had before.
“We prepared an application to the Norwegian Research Council on this future use of the underground as a research topic, and we are also looking at it from the perspective of planned development of the main cities in Norway – a master plan for using below-ground space, if you like.”
The proposed plan was recently put to the government to consider for funding. About 20 companies and institutes are in the consortium proposing the research project which, if it is granted, would last eight years and have a budget of around NKr170 million (£12.5 million) per year.
As noted, he loves to see bare rock in tunnels. “But I do realise that not everyone feels that way. In this project application we have included people with architectural backgrounds, people with psychological backgrounds, people who understand the things that make people actually feel comfortable about being underground.
“Size is important. Your new Elizabeth Line in London has walkways and caverns three times the diameter of the older lines; they are more like cathedrals, much less oppressive, not claustrophobic at all.
“And lighting and surface textures matter also. We can do wonderful lighting effects on, say underground road intersections and roundabouts.
“So, when we are using these professionals who look at things from a different perspective to tunnellers, we can build-in these elements that can make you feel comfortable, and safe, and at ease when underground. Tunnellers should work with architects, with psychologists, with all the other disciplines. It should be one big, unified project.”
Grøv is also a visionary for long-distance tunnels – super-long ones, and super deep.
“Long-distance corridors undersea from Korea to China, across the Bering Strait, joining Japan to Korea… such tunnels could compete with flight routes.
“Just recently, I read that there is an idea to tunnel across the Persian Gulf, to connect Qatar to Iran. The distance is 190 kilometres. The idea of crossing the Bering Strait was raised by the Russians some fifteen years ago; that is of course today not very likely. A Japan-Korea tunnel has been proposed – that distance is about 130km. If China and Taiwan became friends there could be a tunnel connecting the two. Gibraltar could be connected to Morocco; there are many possibilities where these long tunnels can actually be a solution. That would be looking into the future when it comes to really using the underground.
“I was in Jersey and Guernsey last Spring [2024] and they were looking at the possibility of connecting those two islands, not with Britain but with each other and with France. Given the small populations of those places, even with tourism it would probably not be economically sensible.”
But, then, who would have said that tunnels connecting the Faroe Islands would be economically sensible? There are 18 of them in the North Atlantic, some 655km off the mainland coast of Northern Europe. Fewer than 60,000 people live on the islands.
“I have been working with the Faroe Islands for many years. They have now four subsea tunnels between them and we are planning a fifth one; and, when all these five subsea tunnels are built and are in use there will be a seamless connection amongst the islands. You will be able to drive from the south-western island to the north-eastern one in maybe a couple of hours. It used to take a couple of days.
“So tunnels are playing a very vital role in that environment – in its economy and in the quality of life there. The fact that tunnels are providing connection from island to island makes it viable and possible – and attractive – to actually live on those islands and even develop industries. Many of the large fishing industry firms in Norway operate from those islands and sub-sea road tunnels are a must. Connectivity is such an important term.
And, what of tunnels for transporting water?
“The fact is that water that is not fairly distributed amongst us. There are places that have much too much of it and flood: Louisiana is one example, Bangkok another. There are places that need more water, for drinking and supplying cities. Tunnels could be a solution to that. Again it is about connectivity. The Romans did it on the grand scale two thousand years ago; and now we have the advantage of pumps, which they did not have, so our tunnels do not have to be all downhill.”
There are, of course, technical issues to solve in such schemes. Grøv has played his part in resolving some of those. One of those activities was helping with developing the SINTEF TriPOD.
“TriPOD is a monitoring and follow-up system,” he says. “The concept is something that was first developed when we were working with mines; we needed to demonstrate that we could safely accept the size and shape of the underground caverns without reinforcing the walls.
“Then we brought it into civil purpose activities, such as water and road tunnels. A new tunnel that was being built as part of the Follo rail line, outside Oslo, came within a very small vertical distance of an existing road tunnel. The road tunnel owner said, ‘We will allow you to go ahead with this alignment that you have, but you have to ensure that there no damage will take place on our tunnel.’
“So we developed a concept whereby we could follow-up, very closely, what is actually going on in every metre of tunnel excavated. We were monitoring the deformations, the stress situation in the area. We had a traffic light system, of green, orange and red. We decided levels for each of these colours so when the deformations or the stresses reached something which was within the green it meant ‘just go ahead, there nothing particular to do’; orange meant ‘stop a bit, see what is happening’; and, when it was red it was full stop. We used this during the excavation stage of the Follobanen tunnel and it worked very well.
“We also used the system for a water supply project. There were of course long tunnels to conduct the water but there were also some parallel large rock caverns used for cleaning the water to make it drinkable.
“The rock reinforcement systems that were designed for these caverns were quite significant, so the owner wanted us to put together a monitoring system that would record their stability with the different types of reinforcement systems that were engaged. We could document the way these caverns responded with the respective reinforcements, and the end result was that we could use much less reinforcement. We could document that these caverns are stable with these lesser amounts of reinforcements, and the net result was that the owner had a saving of NOK 100 million (£7.3 million) or something along those lines. They had a significant saving; that was a result of TriPOD.”
With much engagement with so many people, across so many countries and different types of underground projects, and their geologies and possibilities, and challenges, he has worked in multiple settings – with various consulting companies until 2005, and then research body SINTEF, as Chief Scientist. That position saw him based in Trondheim and with the opportunity to teach at NTNU, lecturing and supervising students, giving back to the place where he started his own academic journey.
But engaging with tunnelling colleagues in the national society, NFF, was also important from early on. From the mid- 90s he represented NFF internationally to the nation gatherings at the General Assembly of the International Tunnelling and Underground Space Association (ITA-AITES). He would eventually lead NFF, as President, over 2009-2011. Following on, he led the Norwegian Tunnelling Network (part of NFF) for several years.
Those formal international contacts with ITA also saw much work in support of its activities for the tunnelling industry, accelerating from the late 90s when its World Tunnel Congress (WTC) was hosted by Norway, in Oslo. Starting as a Vice Animateur to Working Group 4, in 2000, he eventually joined the Executive Council in 2004, became Vice President in 2007 and a Presidential candidate in 2010 – while leading NFF. He maintained his active engagement in ITA, as an Animateur of a Working Group until 2019. At that point he became a key member of the newly established, two-person Governance Council, giving to the role for three years and through the Covid period.
With much focus on underground space through his life, his love of sport on the surface has not faded. “The interest in cross-country skiing has followed me throughout my life, my wife is a former cross-country skier, our four children have all been cross-countries skiers and engaged in the sport in various ways.” Helping to organise and share is never far away and, previously, he led a skiing club in Trondheim and is currently president of an annual skiing day – ‘Barnas Skidag’ – for children and young people, held every March. Around 2500 participants gather.
“Skiing, working and family don’t allow space or time for much more,” he says.
From an initial love of rock and wanting to be outdoors and travel, he has come far, following his passion and working with many in the tunnelling industry in Norway, Scandinavia and internationally, and he has the vision to help to more.
“There is one big family which is the international tunnel engineering family. I enjoy that. I enjoy going abroad, I enjoy working with different people and learning how they see things and how we should be careful not to impose. The way that we do things in Norway doesn’t necessarily fit 100 percent somewhere else; but if 90 percent of it fits then you adapt the last ten percent to the local circumstances and you get something that works.
“After all, learning about other cultures and adapting your view to them is part of the human experience. That way it appears that tunnelling is a universal language; or perhaps it is a universal skill.”
