Nam Wan Tunnel
Encyclopedia
Nam Wan Tunnel is a tunnel
in Hong Kong
which has been completed and is scheduled for opening to traffic on 20 December 2009, along with the West Tsing Yi Viaduct, East Tsing Yi Viaduct and Stonecutters Bridge
. The road tunnel, which will form an important part of the HK$15bn Route 8, linking Tsing Yi
and Sha Tin
in the city, has been under construction since 2003 and was completed in 2007.
The twin-tube tunnel, built by the Hong Kong Highways Department, is 1.2 kilometre (0.745647283979768 mi) long and have three lanes in either direction in the southern part of Tsing Yi from Sai Tso Wan
to Nam Wan Kok
. It will provide linkage between the eastern part of the New Territories
and Chek Lap Kok International Airport.
Once opened, the tunnel will be toll-free. The twin tunnels are 15 metres (49.2 ft) wide with 12 cross passages emergency walkways, and a portal building at each end. It was formed by blasting through granite and volcanic rocks.
Nearly all of the 550000 cubic metres (19,423,066.4 cu ft) of tunnel spoil will be reused in the Penny's Bay
reclamation project or processed into aggregates at a local quarry. Spoil will be taken away by a fleet of trucks, one leaving the site every 100 seconds during the working day from 8am to 7pm.
, and continuous monitoring to ensure noise and vibration limits are not exceeded during tunnel blasting; blast doors for any blasting conducted near roads; and 40 water sprinklers and washing facilities at all exits for vehicles to use before leaving the construction site.
. The approximate height and width of the arch is 11.2m and 15.3m respectively. The geology comprises coarse volcanic ash tuff
on the west side and medium grained granite
on the eastern side. Both of these lithologies are intruded by Rhyolite dykes together with some porphyrytic granite and occasional basalt dykes.
The two tubes are constructed using the drill / blast method. Temporary support for the tunnels have been provided by rock-bolts. Permanent support have been provided by a concrete lining of varying thickness depending upon the stability of the ground.
Three main types of support have been used: 400mm un-reinforced, 500mm un-reinforced, and 600mm reinforced.
The cost for the tunnel has been estimated at HK$470m (civil works) and HK$83 million (electrical and mechanical systems). Fläkt Woods is providing the ventilation system for the tunnel.
COWI has provided specialist assistance to Ove Arup and Partners with the design of electrical and mechanical systems for the Nam Wan Tunnel and two adjoining viaducts.
Fläkt Woods will run one of the fans continuously to self destruct, to prove their capability of withstanding temperatures of up to 400°C for one hour. The fans incorporate guide vanes for flow straightening to achieve maximum performance and will run at 995rpm.
Later in the project COWI reviewed the client's detailed design of electrical and mechanical systems.
The electrical and mechanical systems has included the following: high- and low-voltage distribution (11kV/0.4kV); reliable power supply based on UPS and diesel generators; tunnel lighting and road lighting; lighting in portal buildings, technical rooms and cross passages between tunnels; Central Monitoring and Control System (CMCS); fire detection system; public mobile communication system; fire fighting equipment, including fire water booster pumps, hydrants and portable extinguishers; tunnel ventilation for normal operation, congested operation and emergency situations (smoke control); smoke extraction system; pressurised air supply; HVAC and plumbing in portal buildings.
Walk for Millions was held on 15 November 2009 to allow the public to walk across Stonecutters Bridge
and East Tsing Yi Viaduct and through Nam Wan Tunnel. Over 30,000 participants took part, raising more than HK$10 million for the charity's Children and Youth Services.
Tunnel
A tunnel is an underground passageway, completely enclosed except for openings for egress, commonly at each end.A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers...
in Hong Kong
Hong Kong
Hong Kong is one of two Special Administrative Regions of the People's Republic of China , the other being Macau. A city-state situated on China's south coast and enclosed by the Pearl River Delta and South China Sea, it is renowned for its expansive skyline and deep natural harbour...
which has been completed and is scheduled for opening to traffic on 20 December 2009, along with the West Tsing Yi Viaduct, East Tsing Yi Viaduct and Stonecutters Bridge
Stonecutters Bridge
Stonecutters Bridge is a high level cable-stayed bridge which spans the Rambler Channel in Hong Kong, connecting Nam Wan Kok, Tsing Yi Island and Stonecutters Island...
. The road tunnel, which will form an important part of the HK$15bn Route 8, linking Tsing Yi
Tsing Yi
Tsing Yi , or Tsing Yi Island is an island in the urban area of Hong Kong, to the northwest of Hong Kong Island and south of Tsuen Wan. With an area of 10.69 km², the island has extended drastically by reclamation along almost all its natural shore and the annexation of Nga Ying Chau and Chau...
and Sha Tin
Sha Tin
Sha Tin, also spelled Shatin, is an area around the Shing Mun River in the New Territories of Hong Kong. Administratively, it is part of the Sha Tin District.-Geography:...
in the city, has been under construction since 2003 and was completed in 2007.
The twin-tube tunnel, built by the Hong Kong Highways Department, is 1.2 kilometre (0.745647283979768 mi) long and have three lanes in either direction in the southern part of Tsing Yi from Sai Tso Wan
Sai Tso Wan
There are several places in Hong Kong with the name Sai Tso Wan:*Sai Tso Wan, Lantau on Lantau Island, New Territories, near Sham Wat*Sai Tso Wan, Kowloon in Kwun Tong District, Kowloon, near Lam Tin and Cha Kwo Ling - see Sai Tso Wan Recreation Ground...
to Nam Wan Kok
Nam Wan Kok
Nam Wan Kok is a cape in the southeast corner of Tsing Yi Island. It coast was reclaimed and became Container Terminal 9. The Nam Wan Tunnel and Stonecutters Bridge meet there....
. It will provide linkage between the eastern part of the New Territories
New Territories
New Territories is one of the three main regions of Hong Kong, alongside Hong Kong Island and the Kowloon Peninsula. It makes up 86.2% of Hong Kong's territory. Historically, it is the region described in The Convention for the Extension of Hong Kong Territory...
and Chek Lap Kok International Airport.
Once opened, the tunnel will be toll-free. The twin tunnels are 15 metres (49.2 ft) wide with 12 cross passages emergency walkways, and a portal building at each end. It was formed by blasting through granite and volcanic rocks.
Nearly all of the 550000 cubic metres (19,423,066.4 cu ft) of tunnel spoil will be reused in the Penny's Bay
Penny's Bay
Penny's Bay or Chok Ko Wan is a bay in north-eastern Lantau Island, and is the site of the Hong Kong Disneyland Resort, which consists of the Hong Kong Disneyland theme park, Disneyland Hotel, and Disney's Hollywood Hotel, and the Inspiration Lake. It is connected by a highway and a rail...
reclamation project or processed into aggregates at a local quarry. Spoil will be taken away by a fleet of trucks, one leaving the site every 100 seconds during the working day from 8am to 7pm.
Environmental measures
Environmental measures taken to minimise noise and nuisance to road users and the public included: a 7.5m-tall noise barrierNoise barrier
A noise barrier is an exterior structure designed to protect sensitive land uses from noise pollution...
, and continuous monitoring to ensure noise and vibration limits are not exceeded during tunnel blasting; blast doors for any blasting conducted near roads; and 40 water sprinklers and washing facilities at all exits for vehicles to use before leaving the construction site.
Structure
The tunnel cross section is in the form of an archArch
An arch is a structure that spans a space and supports a load. Arches appeared as early as the 2nd millennium BC in Mesopotamian brick architecture and their systematic use started with the Ancient Romans who were the first to apply the technique to a wide range of structures.-Technical aspects:The...
. The approximate height and width of the arch is 11.2m and 15.3m respectively. The geology comprises coarse volcanic ash tuff
Tuff
Tuff is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption. Tuff is sometimes called tufa, particularly when used as construction material, although tufa also refers to a quite different rock. Rock that contains greater than 50% tuff is considered...
on the west side and medium grained granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
on the eastern side. Both of these lithologies are intruded by Rhyolite dykes together with some porphyrytic granite and occasional basalt dykes.
The two tubes are constructed using the drill / blast method. Temporary support for the tunnels have been provided by rock-bolts. Permanent support have been provided by a concrete lining of varying thickness depending upon the stability of the ground.
Three main types of support have been used: 400mm un-reinforced, 500mm un-reinforced, and 600mm reinforced.
Contractors
Ove Arup and Partners Hong Kong Ltd were the designers of the tunnel and Gammon Skanska and Skanska International Civil Engineering joint venture are the main construction contractors (contract was awarded in January 2003). The contract also covered construction of tunnel control buildings and the 1.4 km dual three-lane West Tsing Yi Viaduct.The cost for the tunnel has been estimated at HK$470m (civil works) and HK$83 million (electrical and mechanical systems). Fläkt Woods is providing the ventilation system for the tunnel.
COWI has provided specialist assistance to Ove Arup and Partners with the design of electrical and mechanical systems for the Nam Wan Tunnel and two adjoining viaducts.
Ventilation
Fläkt Woods has provided the ventilation solutions by supplying three immense fans for the tunnel. The axial flow fans measure 2.65m in diameter, are powered by 900 kW motors and run at pressures of 3,800Pa.Fläkt Woods will run one of the fans continuously to self destruct, to prove their capability of withstanding temperatures of up to 400°C for one hour. The fans incorporate guide vanes for flow straightening to achieve maximum performance and will run at 995rpm.
Electrical and mechanical systems
In the preliminary design phase of the tunnel COWI established an overall concept for the electrical and mechanical systems with emphasis on safety-related functions such as electric power supply, tunnel lighting, fire fighting, tunnel ventilation and smoke extraction. This overall concept was used as a basis for the detailed design.Later in the project COWI reviewed the client's detailed design of electrical and mechanical systems.
The electrical and mechanical systems has included the following: high- and low-voltage distribution (11kV/0.4kV); reliable power supply based on UPS and diesel generators; tunnel lighting and road lighting; lighting in portal buildings, technical rooms and cross passages between tunnels; Central Monitoring and Control System (CMCS); fire detection system; public mobile communication system; fire fighting equipment, including fire water booster pumps, hydrants and portable extinguishers; tunnel ventilation for normal operation, congested operation and emergency situations (smoke control); smoke extraction system; pressurised air supply; HVAC and plumbing in portal buildings.
Walk for Millions
Prior to its formal commissionining, a Community ChestCommunity Chest
Community Chest may refer to any of the following:*The Community Chest of Hong Kong*The Community Chest of Singapore*Community Chest , a forerunner of the United Way of America...
Walk for Millions was held on 15 November 2009 to allow the public to walk across Stonecutters Bridge
Stonecutters Bridge
Stonecutters Bridge is a high level cable-stayed bridge which spans the Rambler Channel in Hong Kong, connecting Nam Wan Kok, Tsing Yi Island and Stonecutters Island...
and East Tsing Yi Viaduct and through Nam Wan Tunnel. Over 30,000 participants took part, raising more than HK$10 million for the charity's Children and Youth Services.