As project manager of London’s $1.2 billion Silvertown Freeway Tunnel, Juan Angel Martinez Díaz successfully adopted hovercraft-like skids to turn the job’s 39-foot-diameter tunnel shield for driving the two holes of the 0.9-mile crossing, saving critical time on the project. busy schedule
After completing the southbound journey across the River Thames, the 1,600-tonne shield was turned in a shaft on the south bank and launched with its train on the northbound drive. The whole operation lasted six weeks less than the 120 days allowed, says Martínez Díaz.
He leads the Riverlinx Construction Joint Venture designing and building the tunnel for Riverlinx Ltd. The company has a contract to design, build, finance and operate the crossing with Transport for London (TfL).
Turning the TBM “was quite an impressive implementation”, says Helen Wright, TfL’s head of programme. “They’ve saved time … on something that was really complicated, really new.”
By adopting new techniques in the UK, “the passion for innovation, for engineering… is what shines through,” says John Hagan, CEO of Riverlinx Ltd. “If it wasn’t for him in this role, the project would not be finished on time”, he adds.
An employee of Ferrovial SE, based in Belgium and controlled by the Spanish, Martínez Díaz has led the construction since March 2022, about three years after the contract was signed. Having discarded earlier ideas of lifting the shield with a crane, “we didn’t know how to turn the TBM,” he says.
He decided to adapt the hover-skate technique used by the project’s TBM supplier, Herrenknecht AG, a few years earlier in Germany’s Lider tunnel. The skates sit on cushions of inert nitrogen to eliminate the risk of fire.
Juan Angel Martinez Diaz
Photo by Peter Reina
But as the German tunnellers slid their shield around a hairpin bend, the Silvertown team turned theirs, almost on its own footprint, into a shaft and threw it back across the river.
Martínez Díaz’s team had three and a half months of high pressure to perfect the plan and complete the pit. It took less than a day to spin the skid shield after it hit the pit in February 2023.
Although Wright thinks Martínez Diaz is “really great at creating a vision.” He’s also a very hands-on coach, Hagan adds. “It can spread itself too thin… [but] I know that if I bring a problem to him… he will solve it personally.”
Martínez Díaz admits that he likes to “control everything”, but stresses: “I can’t do anything without my team”. Among the 300 people involved in the project, a handful have been with him since his previous projects in London, he says.
Before the United Kingdom, he had worked mainly in Spain and Chile. And since 2012, it has tunneled some 19 miles under London for the city’s Crossrail, Northern Line and Tideway sewer projects before taking on Silvertown.
Now, with “everything going very well”, he hopes the tunnel will open in time for March 2025. After settling in London with his wife and two teenage sons, and gaining British citizenship , “I’d like to stay,” he says.
