Cross River Rail Shotcrete Lining
In an Australian first, BarChip macro synthetic fibre was used as the primary reinforcement in the commuter rail tunnels of Brisbane’s Cross River Rail shotcrete lining. By the time Cross River Rail broke ground BarChip had already been used in fibre shotcrete linings at Sydney and Melbourne Metro station caverns and pedestrian tunnels.
However, macro synthetic fibre had never been used to reinforce the shotcrete ground support in the driven tunnels of a commuter rail line in Australia. That all changed with Cross River Rail, Brisbane’s first metro tunnel.
The 10.2 km, $6.3 billion project comprises 5.9 km twin tunnels under the Brisbane River and 4 new underground stations. The approximately 3.6 km northern drive of the tunnels were excavated by TBM, while the remaining 2.3 km were excavated by road header. The road header excavation included the southern tunnel drives as well as the station caverns and pedestrian tunnels, all of which used a BarChip macro synthetic fibre reinforced primary shotcrete lining for initial ground support – a first in Australia.
Like on Melbourne Metro, wherever the BarChip reinforced shotcrete lining was in contact with the waterproof membrane, the design team was able to remove the smoothing layer that would otherwise be required with a steel fibre reinforced lining. BarChip was also used to reinforce the concrete track slab across the entire project.