THE first trains on the Forrestfield-Airport Link are expected to run on the line in the second half of 2021 after setbacks including damage to one tunnel and a sinkhole opening up on Dundas Rd.
But the McGowan Government said the project budget remained unchanged.
Transport Minister Rita Saffioti said when the contract was awarded in 2016 by the Barnett government, construction was expected to be completed in late 2020.
Ms Saffioti said on September 22 a leak developed in the tunnel-to-tunnel cross passage 200m north of the Forrestfield station site.
This led to movement in 16 concrete rings and damage to a 26m section of one tunnel and a sinkhole developing alongside Dundas Rd.
“Investigations have indicated a number of potential causes, including construction defects in the grout block or failure of the join between the tunnel lining and grout,’’ she said.
“Tunnelling through the grout block and/or vibration from excavation of the cross passage may also have contributed.
“New measures will be put in place for the construction of future cross passages to reduce the risk of a similar event occurring.
“The construction of the next cross passage is due to start in January’’
She said the 26m damaged section of tunnel 1 had been stabilised and made safe with solid temporary supports.
“Cement grouting has sealed the leaks and the voids created by ring movement.
“Options for a permanent repair include fixing the damage from inside the tunnel or rebuilding the impacted section of tunnel by removing the old rings and casting the new tunnel lining in-situ – either from the surface down, or from within the tunnel. Either solution will be required to achieve the tunnel life of 120 years.’’
“Stabilisation of the ground around Dundas Rd is also ongoing, with two traffic lanes to be opened later this month while compaction works continue.’’