Align JV Reports 112,000 Concrete Segments Installed For HS2 Tunnel

The Align JV consortium has concluded structural work on the 16-kilometre twin-bore Chiltern Tunnel for the HS2 project. A 33-month excavation period, which commenced in May 2021, ended with the emergence of the tunnel boring machines near Great Missenden, Buckinghamshire, in early 2024. The joint venture includes Bouygues Travaux Publics, Sir Robert McAlpine, and VolkerFitzpatrick.

Two 2,000-tonne boring machines were utilized to excavate approximately 3 million tonnes of chalk and flint. The TBMs were launched from a site south of the M25 motorway and advanced at an average rate of 16 metres per day. Construction of 40 cross-passages connecting the northbound and southbound tunnels is also underway.

A total of 112,000 concrete segments, each weighing 8 tonnes, were installed to form the tunnel lining. These components were manufactured at a dedicated pre-cast facility established at the tunnel’s southern portal. The next phase of the project involves the installation of mechanical, electrical, and plumbing systems.

Following the systems fit-out, work will proceed on the installation of slab track and the overhead catenary system required for operation. The infrastructure is designed to accommodate trains travelling at speeds up to 320 km/h as part of HS2 Phase One, connecting London and the West Midlands.