A station box excavated at a record-breaking depth of 50 metres beneath Brisbane has been completed as part of the construction of Brisbane CBD’s first new train station in more than 120 years.
Acting Premier and Minister for State Development Steven Miles said the station box for the new Cross River Rail underground station on Albert Street was about 50 metres deep at its lowest point – almost double the previous record of 26 metres set during Queen’s Wharf construction.
“This dig, in the heart of the CBD, has smashed the previous record, making it the deepest in Brisbane’s history,” Mr Miles said.
“This milestone for Cross River Rail is yet another example of the sheer scale of this project.
“To give an idea of the size, if this was an underground carpark, it would be about 15 levels deep, with excavation generating enough spoil to fill 19 Olympic-sized swimming pools.
“The Myer Centre carpark just up the road has a depth of 22 metres, and this is over double that.
“It is a credit to the over 250 workers on site who achieved this despite challenging engineering conditions in between high-rise buildings in the middle of a bustling CBD.”
Mr Miles said the focus on site would now shift towards permanent building works for the new station.
“The end of excavation means the most intensive period of work on site is now complete, and we thank those living nearby for their patience and understanding while the work took place,” he said.
“As the project progresses this year, we’ll start to see the stations themselves take shape here at Albert Street, but also at our other underground station sites and in the tunnels themselves.
“This month we saw some of the first rail delivered to the Gabba site, which will soon be running down the tunnels.
“The Cross River Rail project has great momentum, and we continue to smash milestone after milestone to the benefit of the Queensland economy.”
Transport and Main Roads Minister Mark Bailey said that the station box formed only one half of the total station area being excavated.
“While excavation of the 50-metre-deep station box cavern has been completed, we continue to work away on the adjoining 290-metre-long station cavern,” Mr Bailey said.
“The Albert Street station will have entrances at both ends, dramatically improving connectivity to not only Botanic Gardens, QUT Gardens Point campus and the new and Queen’s Wharf Brisbane development but also Elizabeth St and Queen Street Mall.
“It’s hard to grasp just how big these stations will be, but just imagine some of Brisbane’s tallest skyscrapers laying horizontally underground.
“With over 67,000 people expected to use the Albert Street station each weekday by 2036, these long platforms are definitely needed.”
Mr Bailey stressed the importance of the new Albert Street station, especially for the 2032 Olympic and Paralympic Games.
“We know how important Cross River Rail was in Queensland’s winning Olympic bid and the crucial role it will play in unlocking the rail network bottleneck over the Brisbane River,” he said.
“As our population continues to boom, I’m sure the extra services we can provide across the whole network will be warmly welcomed by commuters, tourists and games-goers alike.”
Construction of the Albert St station building is expected to be completed in late-2023.
Albert Street station fast facts:
- The fully excavated station box is about 46.4 metres below ground at the main bottom (B10) level, and almost 50 metres below ground level at its deepest point at sump level (about 15 storeys).
- The previous record for the deepest excavation was 26 metres for the Queen’s Wharf development.
- About 47,305 cubic metres of spoil was removed during excavation – the equivalent of about 19 Olympic swimming pools.
- Excavation involved the installation of 340 rock anchors and over 1500 bolts, as well as 4,500 cubic metres of shotcrete.
- About 100 workers are involved in excavating the Albert Street station box, with about 250 workers on the Albert Street site in total.
- While the station platform will be 31 metres below ground, supporting equipment such as tunnel ventilation fans and hydraulic plant rooms mean the station box needs to be excavated deeper.
- Following excavation, work is underway on permanent building structure works, including drainage, waterproofing and concrete works.
- The Albert Street site also includes a 290-metre-long cavern up to 34 metres below ground, which is almost fully excavated, and a northern entrance that will be up to 28 metres deep, and currently about 76 per cent through excavation.
- When completed, the station building itself will be about 40 metres above ground at roof level.
- The station platforms will be 220 metres long, and more than 67,000 people are expected to use the station each weekday by 2036.