Royal Opening for Heathrow Terminal 5Queen Elizabeth II officially inaugurated London Heathrow airport's Terminal 5 (T5) on 14th March, 2008, 53 years after opening the airport's first passenger terminal in 1955. Built on time and on budget, the terminal will open for business for up to 30 million passengers annually on 27th March.Some 60,000 people have worked a total of 100 million man hours to build T5 since construction work began in September 2002. The project team has successfully erected the UK's biggest free-standing building, moved the 900-tonne top cab of a new 87 m-high control tower 2 km across the airfield, tunnelled 13.8 kilometres for rail, road, water drainage and service, diverted two rivers, and installed over 30,000 square metres of glass building facades.Four bored tunnels comprise the T5 project at Heathrow airport: the Heathrow Express rail extension is a twin bore 1.6 km-long tunnel that connects the existing Heathrow Express line to a new underground station at the main T5 building. the Piccadilly line extension is a twin bore 1.7 km-long tunnel that provides an extension from the existing Piccadilly line to a new underground station also at the T5 Terminal. the 4.1 km-long Storm Water Outfall Tunnel (SWOT) is intended to take the increased surface water runoff from the new Terminal 5 and its paved areas to an area 2 km south of the airport. a service tunnel under the A3044 roadway, which provides access to the T5 site from the west for power and other services, involves twin 140 m-long tunnels. The Heathrow Express and Piccadilly line extensions, the SWOT scheme and the service tunnel were built by the Morgan Est / Vinci Construction Grands Projets joint venture using five closed and open-faced tunnel boring machines. Mott Mac Donald was the designer. The project owner is the British Airport Authority (BAA). Read E-News Weekly 10/2005.Underground techniques also included extensive cut-and-cover sections. In some complicated locations, the contractor used a NATM variant without mesh or arches, the sprayed concrete lining (SCL) method. All structures involving the sprayed concrete lining (SCL) were designed by Beton- und Monierbau in association with Mott MacDonald. Rail tunnelsLocated entirely in good clay, the Heathrow Express 5.67 m-diameter tunnels and the Piccadilly 4.5 m-diameter tunnels were driven by open-face TBMs. Both extensions to T5 are in twin tunnels totalling 6.6 kilometres. There are two tunnels of 1.8 km and 1.4 km long for the Heathrow Express and two 1.7 km tunnels for the Piccadilly line extension. Two Dosco boom shield open face tunnelling boring machines were supplied for the Heathrow Express line extension and Piccadilly line extension projects. The Heathrow Express machine featured a 6.11 m diameter while the Piccadilly line machine was 4.8 metre in diameter. The tunnel alignment was controlled by a ZED laser guidance system. Lasers set the cutting profile for the rotating roadheader operator, while the face was excavated with a slight forward incline. Visit www.dosco.co.uk and www.zed-tg.co.uk Heathrow ExpressIn September 2004, the tunnel connection from the current Terminal 4 terminus of the Heathrow Express was connected with T5 for the first time after four and a half months of tunnelling. The tunnel connection was made with a spur tunnel connected to the existing Heathrow Express. The tunnel was lined with 1,419 precast concrete rings containing polypropylene fibre for fire resistance. Excavation of all Heathrow Express structures was completed in January 2005.The project also included three shafts (a 6 m-diameter shaft, a 8.5 m-diameter intermediate shaft, and a 10.5 m-diameter shaft) with the system of cross-passages connecting these shafts with the runningtunnels. The shafts are up to 30 m deep. Their purpose is to provide emergency escape for passengers and ventilation of the running tunnels.Piccadilly lineThe Piccadilly line extension consists of a two-platform station, two sidings where trains can be stabled, a 12.5 m-internal diameter 30 m-deep ventilation shaft and two escape shafts. The new tunnels are connected to the existing loop serving Terminals T1, T2, T3 and T4 by the cut-and-cover construction of the Piccadilly junction box. Excavations of both running tunnels were completed in August 2004. Road tunnelThe Airside Road Tunnel (ART) is 1.42 km long, consisting of 80 m of twin-cell cut-and-cover box at each end, linked by a pair of 1.3 km bored tunnels. Each bore contains an unusual road layout, consisting of a single carriageway 6 m wide with a hard shoulder, enough to allow an airport bus to drive past another bus stopped at the side of the road. The bored tunnels have internal diameter 8.1 m and are connected via a series of cross passages at intervals of 100-130 m designed to ensure the safe evacuation of vehicles or people in the event of a vehicle accident in either tunnel.To drive the shallow road bore, the Morgan Est / Vinci JV using a 9.16 m-diameter Herrenknecht TBM capable of operating in earth pressure balance mode and in closed mode, partly through sands and gravels. Visit www.herrenknecht.comThe excavations were lined with a bolted concrete lining 0.45 m thick: these are unusually strong tunnel segments, required because the ART is so close to the surface and, at one point, passes 3 m over the top of the Heathrow Express tunnel to Terminal 4.The ART forms the link between T5 and the other terminals at Heathrow. It became operational in March 2005. It is used only by vehicles with security clearance. At present, it is mostly used by buses taking passengers from Terminal 3 to aircraft on stands at the west edge of the airport and T5 campus. It is an airside road and so will not be accessible by the general public. Storm water tunnelThe storm water outfall tunnel (SWOT) is also a fundamental component in enabling BAA to recycle the run off water and reuse it in T5's non-potable water system. The tunnel and infrastructure has been designed so that in T5's operational phase, clean water will be pumped back up the tunnel and used in systems such as toilet flushes and heating systems. The SWOT forms the drainage and pollution control system for surface water run-off from the T5 campus to a reservoir 2 km to the south of the airport. At the southern end of the tunnel the run-off water passes through facilities that clean it before it is discharged.An open face Lovat TBM dug the 4.1 km-long 2.9 m-diameter tunnel. The wedgeblock lining was formed by eight 1 m-long 200 mm-thick precast fibre-reinforced concrete segments. The excavation was completed in August 2003. Visit www.lovat.comThe tunnel incorporates four shafts about 20 m deep. Inlet and outlet shafts are 10.5 m in diameter. Two intermediate shafts are 6 m in diameter. They were constructed using the caisson method with precast segmental lining and mechanical excavation supported with a fibre-reinforced sprayed concrete. Service tunnelA twin 140 m-long 2.5 m internal diameter service tunnel under the A3044 roadway, which provides access to the T5 site, was constructed by pipe jack using a Herrenknecht MH2S open face shield equipped with a backhoe for excavation. This service tunnel was required for cables to supply power and pipes to supply water to T5.The construction also included a 24 m x 12 m box and two 6 m-diameter reception shafts, built by the same method as the SWOT shafts (caisson through the gravel and SCL excavation in the clay). All excavations were completed in July 2003.Mucking-outContinuous conveyor systems supplied by Continental Conveyor were utilised for spoil removal from the tunnels, connected to high angle conveyors in the launch chambers and shafts to transfer the spoil to the surface. Visit www.continental-conveyor.co.uk 13/08.