The completion of TBM tunnelling on Heathrow Airport’s Terminal 5 (T5) project (T&TI, February, p7) has not led to a decrease in activity on the site as work continues on track installation and the Piccadilly Line Extension (PiccEx) junction to the existing Piccadilly Line loop serving the airport’s other terminals.
The PiccEx scope called for twin bores of 4.5m i.d. each 1.7km long to link in to London Underground Ltd’s (LUL) existing services (T&TI, July 2004, p20). The tunnels were driven to within 3.5m of the loop. Since January 2005, the loop has been closed as part of a 20 month planned suspension of services while works have been ongoing to form a junction by means of constructing a diaphragm wall box.
T&TI was told that in late September, the junction box works were progressing very well and the box had been excavated to base level. Construction of sprayed concrete eyes was underway to form the start of the four 40m long stub tunnels to provide the connection. The team is said to be ahead of schedule, which has enabled the early handing back of two aircraft stands to the airport.
Track installation has also been ongoing in the PiccEx tunnels, with 2.5km of track installed to date. Of the two 5.7m i.d. 1.6km long bored tunnels that make up the Heathrow Express Extension (HexEx), 750m of sleepers have been laid. Work on the HexEx is set to step up a gear as T&TI was told the track slab pours in the cut and cover boxes and rail station for the PiccEx are almost complete, which will allow work to progress into the HexEx.
Platforms have been built in the T5 station and track is now being laid. Rooms are being built within the station and significant amounts of mechanical and electrical works are being carried out for cabling and ducting.
