Incredible new 10-mile UK tunnel completed – longest on community | UK | News | EUROtoday

Construction has been accomplished on HS2’s longest railway tunnel. The 10-mile-long Chiltern tunnel stretches beneath the Chiltern Hills and can see trains journey at 200mph by it. Two tunnel boring machines, Florence and Cecilia, have been used to excavate the twin-bore tunnel.

Each spectacular machine was designed particularly for the geology of the Chilterns and housed a self-contained underground manufacturing facility. They dug the tunnel and lined it with concrete wall segments as they went alongside, grouting them into place. The TBMs have been run by a crew of 17 operatives working in shifts, supported by greater than 100 folks on the primary compound.

Each of the separate northbound and southbound tunnels was constructed with 56,000 precision-engineered, fibre-reinforced concrete wall segments, HS2 says, all made on the south portal of the tunnel. Around 2.7million cubic metres of fabric have been eliminated throughout the development of the tunnels, which have been then used for landscaping across the south portal web site.

Now, officers say that the closure of labor at two of the road’s Chiltern tunnel vent shafts at Chesham Road and Little Missenden has introduced the venture to an finish.

They added: “Five deep ventilation and access shafts were sunk to depths of as much as 78 metres along its route and completed before the TBMs’ arrival. The understated design of each shaft’s headhouse, by Grimshaw architects, is intended to blend unobtrusively with the surrounding landscape of the Chiltern hills.

“The machines progressed north at a mean pace of 16 metres per day earlier than breaking by close to Great Missenden, Buckinghamshire, in early 2024.

“Since then, work has continued to build the porous extensions to its north and south portals, install its internal walkways and fit out 40 cross passages.”

The head of civil engineering for Chiltern tunnel, Mark Clapp, mentioned: “Multi-faceted projects of the Chiltern tunnel’s scale and complexity don’t often come along; as a civil engineer, you’re lucky to be involved in anything like it. The team we assembled at HS2 Ltd, and with Align JV – our main civil works contractor – and all its subcontractors, to deliver this part of the new high-speed railway, was exemplary.

“I pay tribute to everyone involved. They can all feel certain that their hard work will stand the test of time.”

Align JV venture director, Adrien Baudard mentioned: “Being part of the successful delivery of the Chiltern tunnel has been a source of immense pride for everyone at Align and our partners across the supply chain. Their unwavering commitment, technical skill, and collaborative spirit have been truly impressive.

“Whether it was advancing safety standards, setting new TBM records, or helping to train future engineers, we’ve had the privilege of learning from and working with some of the top talent in our field.

“With the completion of the Chiltern tunnel’s civil works, the achievements of this integrated project team, as well as the sustainable benefits such as carbon reduction and safety innovations, will set a standard in tunnelling for generations to come.”