The 3.2km long, $128M North Downs High Speed Rail Tunnel in Kent, UK has been completed five months ahead of schedule and an impressive $8M under budget.
Excavation was completed last summer when contracting JV, Miller/Dumez-GTM/Beton-und-Monierbau broke through with a Paurat roadheader at the mid-point of the 13m wide x 10m high tunnel.
Since then over 100 workers have been working on a 24 hour day, 7 day week to complete the permanent secondary lining. Using two purpose-made 12m long steel forms filled with more than 220m3 of fibre reinforced concrete a day, contractors managed to complete a total of 120m per week.
Other finishing works include walkways down both sides of the tunnel and a central derailment barrier. The tunnel is now ready for operational fittings.
The tunnel is an integral part of the first section of the Channel Tunnel Rail Link that upon completion in 2003 will carry high-speed Eurostar trains at 300km/h from Waterloo station to the Channel Tunnel.
