The route for the Forrestfield-Airport Link includes 8km of twin-bored tunnels, with safe entry and exit points via underground stations at Redcliffe and Airport Central, as well as tunnel portals at Bayswater and Forrestfield.
Given the length of the tunnels, additional infrastructure is required between the stations to allow safe egress to the ground level in the event of an emergency, and access to the tunnels for maintenance.
As such, three emergency egress shafts (EES), twelve tunnel-to-tunnel cross passages and three tunnel-to-egress shaft cross passages will be constructed along the alignment.
View the cross passage and emergency egress shaft construction fact sheet.
View a map of all cross passage and emergency egress shaft locations.
Emergency Egress Shafts
What is an emergency egress shaft?
An EES provides access from the tunnels to ground level via stairs and lifts.
Its layout is designed in conjunction with the Department of Fire and Emergency Services to ensure functionality during an emergency situation.
It takes up to six months to build each EES and another six months to build the supporting ground level infrastructure (a two-storey portal building, car park and emergency muster point).
The portal buildings house communications, electrical and mechanical equipment and controls. They also contain air vents which will help ventilate the shafts and tunnels.
All three emergency egress shafts are fully excavated, and the respective base slabs have been poured.
The cross passages connecting Abernethy EES to the two tunnels were completed in September 2018. The first of the above-ground supporting buildings has also been erected at this site using tilt-up panels. Scheduled next is the installation of the steel structure to support the roof, before the electrical fit-out of the building can commence.
At Airport West EES excavation has been completed to connect the shaft to the two tunnels. This site is now being used to run ground freezing pipes from the cooling towers to the airside cross passages via Tunnel 1.
Outside the 39m-deep emergency egress shaft at Wright Crescent, the construction of the ground slab is ongoing with the installation of conduits for services such as power, water and firefighting systems now complete.
What is a cross passage?
A cross passage is a short concrete tunnel which provides a link between two main tunnels, or a link between a tunnel and an EES. It takes up to three months to build each cross passage, which are up to 10 metres long and five metres high (around three metres high after final lining installation).
Of the 12 tunnel-to-tunnel cross passage located along the alignment, two have now been completed. Cross Passage Dundas Road was finalised in November 2018 followed by Cross Passage RAC in August 2018.
Crews are now setting up at Cross Passage Car Park C, located just east of Redcliffe Station. Works are also underway to stabilise the ground around the three cross passages located within the airside environment. Drilling works for cross passages Charlie, Papa and Juliet commenced in July 2019 and are approximately 40 per cent complete. Once the ground freezing system has been installed and commissioned, brine will be circulated through the system, with the required ground stability expected to take approximately six weeks to achieve. Excavation is expected to occur late-2019.