‘We hit the jackpot!’ Brisbane’s new runway looks like just another stretch of tarmac – but an incredible discovery beneath it has left engineers shocked
- The runway has been in development for seven years and due to open in 2020
- Engineers on the project were confronted with soil like ‘sticky toothpaste’
- The runway has been one of the biggest engineering challenges in the world
- More than 11 million cubic metres of sand had to be pumped out of Moreton Bay
- They think the Brisbane River ran under the site thousands of years ago
An incredible discovery underneath Brisbane’s new $1.3 billion airport runway has left seasoned engineers and builders shocked.
When machinery dug into the dirt at the site in Brisbane’s northside, engineers were confronted with soil the consistency of ‘sticky toothpaste’.
Runway director Paul Coughlan said it posed a massive challenge trying to achieve a stable base for the second 3.3km runway and attached 12km of taxiways.
What they found below the surface was an even bigger surprise and one he describes as the ‘jackpot’.
An incredible discovery underneath Brisbane’s new $1.3 billion second runway construction (pictured) has left engineers shocked.
‘Our geotechnical engineers back in 2005 and 2006 discovered running across the runway site was probably the old Brisbane River. And rivers over thousands of years meander,’ Mr Coughlan told The Courier Mail.
‘I think we were expecting poor soils but we hit the jackpot, which as an engineer you don’t want to hit, which is the worst you could have.’
He said the engineers are building up the site in terms of height and also weighing it down to compress the topsoil.
The second runway has been one of the biggest engineering challenges in the world due to its location.
More than 11 million cubic metres of sand was pumped out of Moreton Bay and on to the new runway site.
The sand was left to settle for three years – slowly weighing down the soil so that the water was squeezed to the top and pumped away.
Site works at the new Brisbane Airport runway have shifted millions of cubic metres of topsoil
Over time the ground sunk as much as three metres in some areas.
After this time construction on the actual runway itself then began in 2017 – with 2 million cubic metres of sand scraped from the top of the site – having done its job.
The runway is expected to open in mid 2020 with construction being completed later this year.
The new runway is expected to generate 7,800 new jobs once completed