News Articles | 15 June 2018

Following TBM Grace’s arrival at Airport Central Station on May 8, TBM Sandy also broke though into the station’s underground box late last month.


The machines were guided through a 12.5m block at track level of the future station, approximately 17m below ground. Having tunnelled 1.9km from the launch site at Forrestfield, the machines are required to undergo a detailed maintenance program where they are cleaned, worn cutter head tools are replaced, and routine servicing and testing of mechanical and electrical equipment is conducted.

TBM Grace’s maintenance program is nearing completion and the machine is expected to be relaunched towards Redcliffe by the end of the month. TBM Sandy will follow shortly afterwards to maintain a safe distance between the machines.

Hive of activity at Airport Central Station 

Demolition of the false block, which was in place to support TBM Grace’s arrival at Airport Central Station, is now complete. This involved break out of the concrete block with a 20T excavator and rock breaker, with the remaining 600m3 craned out of the station box by bins. Demolition of the false block for TBM Sandy will commence this month following the same process.

Steel fixing for the base to concourse level columns is still in progress and will be completed once the TBMs exit the station box. Six of the 20 concourse to ground level columns have now been poured with prefabricated steel formwork to mould the oval-shaped columns. Another four columns will be poured this month, while the remainder will be completed at a later stage.

Construction of the ground egress foundations are now also complete. This involved constructing 5m x 3.5m square footings at the north end of the station box to support the columns for the elevated walkway.

Micro-tunnelling and more in Bayswater 

Excavation has begun within the Bayswater tunnel portal and dive structure, with more than 1000 tonne of soil removed to date (approximately two per cent of the total amount to be excavated from the site).

As part of construction works for the dive structure, a section of a water drain currently situated within the rail corridor in Bayswater needs to be relocated. A 50m wide section of Whatley Crescent will be closed between Anzac Street and Newton Street from 14 June 2018 for up to eight weeks to allow micro-tunnelling for the new drain pipe to occur safely. During this time residents will still be able to access their homes, however vehicle movement in the area will be restricted.

Further along the dive structure, adjacent to Whatley Crescent, work has also begun to construct the concrete slab cross over for the Midland Line. The city-bound train will travel over the dive structure on the overpass bridge before merging with the Forrestfield Line, before Bayswater Station. There will be four separate concrete pours to construct the 100m long slab.

Road works continue at Forrestfield site

The Dundas Road realignment is 60 per cent complete. Traffic management is currently in place as part of construction for the southern intersection, between Berkshire Road and Imperial Street. Works on the northern intersection, just north of Maida Vale Road, will begin in two weeks.

The southern retaining wall is 80 per cent complete with eight of 12 wall panels in place. Over coming weeks, the construction team with finish the concrete work and continue backfilling. 

Redcliffe Station box fully excavated

With the completion of excavation at Redcliffe, work has begun to waterproof the station box.

The first step is the installation of a blinding concrete layer then a waterproof membrane is installed, followed by a protection screed. Waterproofing will take about two months to complete, then construction of the base slab will begin. This involves steel reinforcement and pouring 5500m3 of concrete.

Construction of egress shafts underway

At our first emergency egress shaft (EES), off Abernethy Road, cross passage connections have now been excavated, linking the EES to both tunnels. The construction team is now preparing the cross passages for waterproofing, which will take about one week to complete.

Excavation is currently at a depth of 27m within the Airport West shaft, with seven metres to go. Once completed, the base slab will be constructed.

With the completion of jet grouting at the Wright Crescent EES, core drilling is underway to test the concrete’s strength and permeability. Following this, work will begin to construct capping beams and then excavate the shaft.

Jet grouting has begun at the future cross passage site adjacent to the Tonkin Highway off-ramp, near Guildford Road. This will take approximately one month to complete.

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