Inside the world’s deepest and longest subsea road tunnel

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Niall Firth writes, Inside the world's deepest and longest subsea road tunnel.
It's cold, it's very, very noisy, and if I can be quite honest with you, I'm not feeling super relaxed. I'm currently around 300 meters or 1,000 feet beneath the North Sea, in a dark, dank cave. It smells weird, and I am increasingly aware of the pressure from millions of tons of seawater just above my head, pushing down with a force of more than 500 pounds per square inch. Picture a baby rhino standing on a postage stamp. Only fabulous engineering is keeping me from being crushed, drowned, disappeared. My safety goggles are foggy.
Just a few hundred meters away, someone is about to blow up a giant rock wall. Luckily, earlier that day, I was given a full safety briefing and I've got a special hard hat on. Don't worry if you don't make it. We'll have your stuff sent back to your office. Geologist Anne Moretta Gilyar tells me, straight-faced, Norwegian humor.
I'm in this odd situation under the iconic fjords of Norway to visit what will soon become the world's longest and deepest subsea road tunnel, called Rogfast, short for Roggeland. I want to understand how you make something as audacious as a 26.7 kilometer or 16.6 mile highway, that sits 390 meters or 1,280 feet below the sea at its deepest point. And also at a time when it can feel hard to get anything done, especially in the US, to reassure myself that ambitious engineering is still possible, that we can still make things.
The Norwegians already have the world's longest subsea tunnel. The 14.4 kilometer refuel kia through Rogfast will dwarf it. Their expertise has attracted attention from Japan, Spain, Morocco, and even a number of US states, whose representatives were due to visit the site in May just weeks after I went. They too want to know how Norway does it. The answer? Tons of explosives.
The entire endeavor feels like an obstinate refusal to give into physics and geology. It's always exciting. Nicholas Brucehead, a tunnel foreman at Implenia, a Swiss firm involved in the project tells me, every blast creates a new world. There's not just the blasting of the tunnel itself, although that is an epic project on its own, but an immense logistics challenge involving huge ventilation shafts, extreme pressure, underground roundabouts in complex Norwegian geology. Oh, and the water, so much water. This is the longest continuous blast on the sea, says John Olaf Osterhaus, Assistant Project Manager at Implenia. Never been done before. We can't buy a book to see how we do this. All right, time to fish my phone out of my safety suit. Don't want to forget this.
Arriving at the rock face where the tunnel hit seabed feels like being on the moon. It's a huge slab of stone at the end of a long dark, wet, wide passageway that's lit barely by electric lights. Giant vehicles carting tons of rocks rumble past periodically, and we pull to the side of the road to let them by.
Workers clock in for 12-hour shifts, 6 a.m. until 6 p.m. deep in the bowels of the earth, where no natural light can reach. Twelve days on, 16 days off. They eat their lunch at a table in this damp cave surrounded by port-a-cavins plastered with safety notices. It's kind of a lifestyle, says Bruce Head, laughing. You have to be a little bit crazy to work underground all the time. These crazy engineers are here to make tunnels the Norwegian way. The nation frequently uses what's known as the drill and blast method, instead of the tunnel boring machines that are more typical elsewhere. This approach offers more flexibility for long complex operations with varied rock types. Each blast adds about 5 to 6 meters to the tunnel.
Rogfast is being built inward from the ends to speed things up. The construction company Skanska is leading from the north, coming from the island of West Robokin. Implenia has joined a company called Stangland to tunnel from Randeberg in the south, which is where I am. Both teams use multiple laser scans each day to consistently measure orientation and check that the tunnel is exactly where it should be. The two ends should meet some time in 2029 with no more than just a few centimeters of deviation.