In October 2019, the events company Informa hosted its 16th Australian Tunnelling Conference. Not to be confused with the Australian Tunnelling Society’s (ATS) official conference, but still supported by them, it was an opportunity to get an update on the Australian underground construction market.
In short, things are going incredibly well, according to ATS president Ed Taylor. There is more work than even recent years, and the industry can see a solid 10 years of work ahead of it. Speaking to Tunnels and Tunnelling at the conference he remarks that any industry is always at the mercy of politicians, but the outlook is better than it has ever been.
In Sydney the government is falling over itself to approve funding for the next stages of the city’s metro. During Tunnels and Tunnelling’s visit, the client’s project director Hugh Lawson remarked that most people were probably expecting a 10-year timescale before the second stage (the City and Southwest section featured in this issue) received approval, but this was forthcoming even before the first Northwest stage was completed.
The third, the Western section, was approved in October 2019 with work due to commence in 2020. This project will have the longest rail tunnels ever built in Australia (works will total 50km) and is expected to constitute the largest tunnelling contract in Australian history.
During the Stuva conference in Germany in November, conversations also kept turning towards Australia, which has become an important customer for many companies. As an example, VMT currently takes 20% of its business from Oz.
Back to the conference in Sydney, Taylor delivered his opening address and said that the amount of work warrants increasing the frequency of the triennial conference to a biennial event. He also lauded the ATS’s focus on training, but like many countries, there is a feeling that Australia must do more. There has been talk of support in the form of scholarships, which now need to materialise. The society is also paying attention to the Melbourne training centre and is hoping to run more workshops. The ATS is also a major contributor to international health and safety nous, in particular relating to air quality.
One of the first talks of the event is on the 18km Sydney’s Western Harbour Tunnel and Beaches Link. This new motorway project, part of an AUD 55bn (USD 38bn) suite of work planned by Transport for NSW (which includes the metro) over the next four years, is to set the groundwork to provide appropriate infrastructure for Sydney’s growing population, which looks set to expand from 4.7 to 8.3 million over the next 40 years.
The plan for this project is to get the (future) three harbour crossings “working together”, and like the Sydney Metro, is not necessarily the optimal alignment for the individual project, but is instead designed to improve the network as a whole. In November 2019, Transport for NSW announced that the proposed reference design for the Beaches Link had been completed, while the EIS for the Western Harbour Tunnel was ready to be put to the public in early 2020.
The project is expected to be procured in three major chunks – Warringhah first, Western Harbour second and Beaches third. A structure has not been decided yet, but PPP is attractive to the client. It is expected that there will be a significant schedule buffer between the projects, however.
It is interesting that there is so much work under the harbour in the modern day, and a relative paucity historically. Doug Parris of Transport for NSW suggests that this is because tunnelling technology has reached a maturity and has given planners confidence that they did not have in previous years.
The 33km-long WestConnex, Sydney’s other major motorway project, continues to progress. The M4 East opened in July 2019 and Stage 3 M4/M5 main tunnels are currently the main focus. The AUD 16bn (USD 11bn) project had a major focus on its training academy owing to labour shortages, but also managed to include cycle paths (which is always a positive for a modern infrastructure project), is the first Australian road project to use BIM, and the 22km of tunnel even necessitated research into how to keep drivers engaged.
But there is life outside Sydney. Melbourne, traditionally the second city, is set to overtake Sydney and become the largest city in Oceania by 2026. North and west Melbourne in particular are experiencing unprecedented growth, and infrastructure investment has followed. The Melbourne Metro Tunnel project has seen four TBMs delivered to build 9km of new twin-tube metro tunnels. The new line will see five new underground stations – one top-down, two bottom-up and two mined. There is also some roadheader work in the central section. There is also a sizeable investment in the sewerage network expected for the future, according to Ed Taylor. It is not surprising that this growing city will host the main Australian conference in 2020.
Heading west (a long way west) to Perth, the world’s most isolated city, the Forrestfield-Airport Link is continuing apace. There will be more on this project in a subsequent issue, but in short, two 7m-diameter variable density TBMs from Herrenknecht are boring 8km of tunnels to link the airport and an eastern suburb in need of regeneration with the centre of the city. The key point of the project will be the under-passing of the active airport runway.
And finally the Snowy 2.0 project. Located between Melbourne and Sydney, this project, with a business case that is controversial to some, is a major pumped storage expansion of the original Snowy scheme, which will increase its generation capacity by 2GW when needed and provide up to 10% of Australia’s power demand. All this within 190 seconds, which is very attractive following recent blackouts in South Australia.
If all goes well, first power is expected in 2024/25, but before then a number of challenges have to be overcome. The project has been looked at before, in 1980 and 1990, but the sheer length of the 27km of 9m-diameter tunnels to link two reservoirs to a powerhouse some 800m underground was prohibitive. Then there are the 36 different strata to be negotiated, as well as a 250km-long fault that is 1.5km wide where the tunnel alignment crosses it. Three TBMs will execute the bore, which includes a 25° inclined pressure tunnel, and may comprise the largest hydraulically-loaded tunnel in the world, with a 5m/s water flow. The power station cavern will be 250x50x30m and the worksite for the 2,000-strong workforce will constitute the third-largest town in the region.
So as not to scare away contractors, Snowy is taking the ground risk.
For readers unfamiliar with the original Snowy Mountains scheme, it is wellworth the time taken to read about. Try The Snowy: a history by S. McHugh.
The project comprises 145km of interconnected tunnels that were dug in the decades following World War 2. The scheme required a workforce of 100,000 and spurred migration levels that shaped the Australian nation. It is an iconic job that heavily influenced the construction culture. For example, competition between day and night shifts resulted in rushing, which in turn resulted in fatalities. Another challenge was posed by lightning strikes grounding themselves and causing material and equipment explosions underground. It is a spectacular story.
Back to the present, the market looks strong, and while there are risks to all projects in general, the sun looks set to shine on Australia for the foreseeable future.
