- A long-awaited tunnel on a Surrey stretch of the A3 in the UK is open on time and on budget after a four-year construction project. The 1.9km tunnel, the longest of its type in Britain, is part of a 6.4km bypass of the Surrey village of Hindhead. The tunnel will reduce the journey time between London and Postsmouth and remove a well-reowned congestion blackspot.
A police escort for the first users
- The southbound tunnel was officially opened by Transport Secretary Philip Hammond at 10.38am - eight minutes later than scheduled. A meeting is due to be held soon to decide on an opening date for the northbound stretch, which still requires some final completion works.
- Cars, lorries, motorcycles and taxis sounded their horns as they were given a police escort through the new tunnel on Wednesday morning (July 27, 2011).
- At the opening ceremony Secretary Hammond said: "I have spent a sizeable proportion of my adult life waiting at the crossroads in Hindhead. As an MP for Surrey I have long recognised this as one of the few busy links [in the UK] that could really make a difference to our transport infrastructure network.
- "Now we have filled this missing link people will see journey times very significantly reduced and it will make the length of journeys much more certain."
- He added: "What is so special about this project is the delivery of a state-of-the-art transport structure which not just protects the local environment but actively enhances it. It is unique."
Secretary Hammond does the honours
- The section of the old A3, which the bypass replaces, will stay open for the moment but work to return it to its natural state is expected to start during the middle of August.
On budget and on schedule
- The £371 million ($606 million) project has been in planning since as long ago as 1983. Work finally started in January 2007 to create the twin tube tunnel under the Devil's Punch Bowl on the A3 near Hindhead in Surrey. Both bores broke through in February 2009.
- About 30,000 vehicles are expected to use the new road every day when it gets up to capacity. The project has won awards for its innovation and its safety record, and has been delivered within budget and on schedule.
- Balfour Beatty won the £186 million twin tube tunnel contract, which includes 16 cross passages, one every 100m (328ft), and 34 emergency niches. About 90% of the tunnel was excavated from the north portal through sandstone and about 10% from the south portal through sand. At its deepest point the tunnel is 65m (213ft) underground. The SCL (sprayed concrete lining) tunnel includes a sprayed-on waterproofing system.
In December 2010, the project received an International Tunnelling
Project of the Year award.
How it was done: Hindhead bypass in pictures Jul 2011
Construction of the 1.9km-long Hindhead tunnel, part of a 6.4km-long bypass project on the busy A3 between London and Portsmouth, started in January 2007.
Here, in pictures (courtesy of the Highways Agency, which funded the £371 million ($605 million) project, TunnelTalk charts the progress, both above and below ground, of the UK's longest road tunnel of its type to date.
The old A3 from the air
- 1. The existing A3
- The old A3 runs along around the Devil's Punchbowl, an area of natural beauty. The road is the only section of single carriageway on the A3 outside London.
- The existing road is a daily source of congestion for drivers, is unpopular with Hindhead village residents, and cuts straight through the internationally-prized area of countryside.
- 2. Mapping it out
- The old single-carriageway A3 curves around the hillside and runs very close to Hindhead village. The new tunnelled route is dual carriageway, eliminates a notorious local traffic light holdup on the highway, and bypasses the village altogether.
Clearing the land
- 3. Clearing the way
- Construction of the new road began in January 2007 with extensive vegetation clearance, much of it from existing commercial woodland. A total of 2,173 tonne of timber was removed during this phase. More than 20,000 new trees and shrubs are replanted. The old A3 is in the bottom left of the image.
Tunnelling starts at south side
- 4. South portals begin
- The ground at the south portal. The Alwag pipe-umbrella system was used to provide a safe pre-support canopy under which excavation advanced.
Digging the sandstone
- 5. Digging away
- Excavation of the sandstone is advanced in 1m-3m topheading rounds.
A 24 hours a day operation
6. Hard day's night
Tunnelling work continued 24 hours a day, seven days a week for more than a year.
- 7. Tunnel breakthrough
- 26 February 2009: After a year of 24/7 excavation from both ends, breakthrough was achieved some 40m below Hindhead Common. The breakthrough was witnessed by special guests, tunnel workers and the regional and national media.
- 8. Waterproofing
- With excavation complete, a waterproof layer was added behind the final lining and to the primary lining. A sheet membrane was applied to the tunnel walls while the BASF spray-applied membrane was applied to the tunnel crown to save time and money. The BASF robots that applied the primary shotcrete lining applied the spay-on membrane.
Secondary lining shutter
- 9. Secondary lining shutter
- An in-situ concrete final lining was applied to the tunnel walls using a 12m-long shutter moved along on tracks. As well as improving visibility along the tunnel, the painted concrete walls allow for wash-down and provide additional fire resistance. Shotcrete provides the final permanent lining in the crown.
- 10. Duct installation
- Meanwhile, underground, teams were busy installing the ducts that would carry the cables serving the tunnels' lighting and safety systems. More than 100 miles of cable have been installed.
- 11. The road is layed
- Mid-2010: The tunnel is now looking almost complete with the road deck also installed.
- 12. Cut and Cover
- Concrete structures extending from the cut-and-cover portals will be backfilled to blend into the surroundings hillside.
Open day - May 2011
- 13. Community Day
- An opportunity for 7,000 people to walk through the new tunnel in May 2011, proved enormously popular. Ticket sales to be part of the event raised £12,000 for charity in the process.
Philip Hammond opens Hindhead tunnel
14. Tunnel opening ceremony
UK Transport Secretary Philip Hammond cut the ribbon to open the new southbound tunnel and bypass on Wednesday 27 July, 2011. The northbound section of the tunnel will open soon.
Thousands celebrate UK's longest road tunnel - TunnelTalk, May 2011
UK applies spray-on waterproofing - TunnelTalk, March 2010
Add your comment
- Thank you for taking the time to share your thoughts and comments. You share in the wider tunnelling community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language professional.