Heathrow Cargo Tunnel
Encyclopedia
The Heathrow Cargo Tunnel is a road tunnel in the London Borough of Hillingdon
, London, UK that serves London Heathrow Airport
.
bus service (route 82) operated through the tunnel. In 1986, when Terminal 4 opened, a number of other bus routes then also passed through the tunnel. This was an unusual situation, because anyone could board the bus, and travel "airside" without going through any security checks. In 1989, in the interests of security, all public bus services were withdrawn from the tunnel. All public buses now enter the central area through the main tunnel.
The bored tunnel segments are precast concrete, with a 33 inch internal diameter and 12 in (30.5 cm) thick. The segments are expanded directly against the ground, which is London Clay
. The bored section of the cargo tunnel is notable among tunneling engineers, for having been constructed with a remarkably thin cover of solid clay above it (minimum cover 1.2 m (3.9 ft) clay beneath the Terrace gravels).
There is one sump
in the tunnel, at a low point about 300 m (328.1 yd) north of the south portal.
The tunnel is one of the few in the United Kingdom that is ventilated by a fully transverse system - it has an air supply duct in the invert of the tunnel, and an air extract duct in the crown of the tunnel. Extraction and supply fans are sited in underground chambers at the north end and the south end of the tunnel, at the Tunnel Boring Machine
(TBM) launch and retrieval chambers.
Consulting Engineer for the works was Sir William Halcrow and Partners
, with Hoare Lea & Partners advising on electrical and mechanical services. The tunnel was built by Taylor Woodrow Construction
, with E&M fitout by Halliday Hall and Aerex.
The cargo tunnel was the only privately operated road tunnel in the United Kingdom until March 2005, when the Heathrow Airside Road Tunnel
was opened to airside traffic next to it.
London Borough of Hillingdon
The London Borough of Hillingdon is the westernmost borough in Greater London, England. The borough's population was recorded as 243,006 in the 2001 Census. The borough incorporates the former districts of Ruislip-Northwood, Uxbridge, Hayes and Harlington and Yiewsley and West Drayton in the...
, London, UK that serves London Heathrow Airport
London Heathrow Airport
London Heathrow Airport or Heathrow , in the London Borough of Hillingdon, is the busiest airport in the United Kingdom and the third busiest airport in the world in terms of total passenger traffic, handling more international passengers than any other airport around the globe...
.
History
In December 1968, the tunnel first opened, to connect Terminals 1, 2 and 3 to the newly opened cargo terminal at Heathrow, and it cost £2 million to build. The tunnel is not open to the public; it is used only by vehicles with security clearance to drive airside. It is presently used for cargo movements, and transfer of passengers to and from Terminal 4 (In 1986, Terminal 4 was built next to the cargo terminal). From 1972, a London TransportLondon Transport
London Transport could refer to:*London Transport Transport authorities that operated services under the brand:*London Passenger Transport Board *London Transport Executive *London Transport Board...
bus service (route 82) operated through the tunnel. In 1986, when Terminal 4 opened, a number of other bus routes then also passed through the tunnel. This was an unusual situation, because anyone could board the bus, and travel "airside" without going through any security checks. In 1989, in the interests of security, all public bus services were withdrawn from the tunnel. All public buses now enter the central area through the main tunnel.
Design and construction
The cargo tunnel is bi-directional; it has one bore, carrying one lane in each direction. Each lane is 12 ft (3.7 m) wide, with a clear height of 16 inch. The tunnel consists of approximately 625 m (683.5 yd) of circular bored tunnel plus 130 m (142.2 yd) of rectangular cut-and-cover tunnel at each end. Its total length is 885 m (967.8 yd).The bored tunnel segments are precast concrete, with a 33 inch internal diameter and 12 in (30.5 cm) thick. The segments are expanded directly against the ground, which is London Clay
London Clay
The London Clay Formation is a marine geological formation of Ypresian age which crops out in the southeast of England. The London Clay is well known for the fossils it contains. The fossils from the Lower Eocene indicate a moderately warm climate, the flora being tropical or subtropical...
. The bored section of the cargo tunnel is notable among tunneling engineers, for having been constructed with a remarkably thin cover of solid clay above it (minimum cover 1.2 m (3.9 ft) clay beneath the Terrace gravels).
There is one sump
Sump
A sump is a low space that collects any often-undesirable liquids such as water or chemicals. A sump can also be an infiltration basin used to manage surface runoff water and recharge underground aquifers....
in the tunnel, at a low point about 300 m (328.1 yd) north of the south portal.
The tunnel is one of the few in the United Kingdom that is ventilated by a fully transverse system - it has an air supply duct in the invert of the tunnel, and an air extract duct in the crown of the tunnel. Extraction and supply fans are sited in underground chambers at the north end and the south end of the tunnel, at the Tunnel Boring Machine
Tunnel boring machine
A tunnel boring machine also known as a "mole", is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. They can bore through anything from hard rock to sand. Tunnel diameters can range from a metre to almost 16 metres to date...
(TBM) launch and retrieval chambers.
Consulting Engineer for the works was Sir William Halcrow and Partners
Halcrow Group Limited
Halcrow Group Limited is an engineering consultancy company, based in the United Kingdom.Halcrow is one of the UK's leading consultancies, with a pedigree stretching back to 1868. The UK-based consultancy specialises in the provision of planning, design and management services for infrastructure...
, with Hoare Lea & Partners advising on electrical and mechanical services. The tunnel was built by Taylor Woodrow Construction
Taylor Woodrow
Taylor Woodrow was one of the largest British housebuilding and general construction companies. It was listed on the London Stock Exchange and was once a constituent of the FTSE 100 Index but merged with rival George Wimpey to create Taylor Wimpey on 3 July 2007.-Early years:Frank Taylor was...
, with E&M fitout by Halliday Hall and Aerex.
The cargo tunnel was the only privately operated road tunnel in the United Kingdom until March 2005, when the Heathrow Airside Road Tunnel
Heathrow Airside Road Tunnel
The Heathrow Airside Road Tunnel is a tunnel at London Heathrow Airport. It connects the airside roads around Terminals 1, 2 and 3 to the airside roads around Terminal 5....
was opened to airside traffic next to it.