Emergency exit points
After waterproofing was completed, the permanent concrete between the tunnels and the emergency egress shaft (EES) near Abernethy Road has been poured and focus will now shift to construction of the staircase, lift shaft and ancillary building.
At Airport West EES the base slab has been poured and the shaft is awaiting the arrival of the TBMs later this year before works can commence on the cross passages connecting the shaft to the two tunnels.
After completing the capping beam for the Wright Crescent EES in Bayswater, excavation of the 2500 tonnes of soil is now almost complete within the 9m diameter shaft. Once all the soil is excavated, the base slab will be poured to seal the underground structure.
While the TBMs are progressing well, the recent leak at the project's first tunnel-to-tunnel cross passage requires ongoing assessment and repair. Jet grout was injected into the ground late last year in preparation for the cross passage to be constructed. In this instance, a leak occurred during construction allowing groundwater and silt to flow into the cross passage and one of the tunnels. As a result, a sink hole formed at the surface above the cross passage, about 200m north of the Forrestfield Station site where the tunnels follow the alignment of Dundas Road. The leak has now been stopped and efforts have shifted to repairing damage caused by the leak, including the reinstatement of Dundas Road.
Cross passages and emergency egress shafts
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. Trains will enter the underground rail line via 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, 12 cross passages and three emergency egress shafts will be built along the alignment.
View the emergency exit points fact sheet.
The cross passages are located at numerous points along the route to provide a connection between the tunnels. In the unlikely event of an emergency, passengers will be able to exit the train and use the tunnel walkways to locate the nearest cross passage. They will then be able to enter the adjacent tunnel safely and exit through the nearest emergency egress shaft, station or dive structure.
Cross passages are constructed using the jet grouting process, a construction technique used to improve ground conditions and stabilise soils in preparation for tunnelling works.
Emergency egress shafts
Emergency egress shafts provide emergency exit points for passengers along the tunnel alignment. In the event of an incident, commuters will access the emergency egress shafts using the cross passages and walkways within the tunnel. They will then be able to use either the stairs or the lift contained within the emergency egress shaft to reach ground level.
The shafts lead to 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.
Emergency egress shafts will be built in three locations along the alignment:
- Wright Crescent, Bayswater
- Woods Road, within the Terminal 3 & Terminal 4 Precinct (Airport West)
- Abernethy Road, Forrestfield