Over the past few years tunnelling has really taken off in Australia although recently the focus has moved from Sydney to Brisbane. The recent 13th Tunnelling Conference held by the Australasian Tunnelling Society in Melbourne attracted over 350 attendees and papers were presented on a variety of tunnel projects planned and under construction. Tunnelling in New Zealand has begun to expand in recent years as well and the Australasian Tunnelling Society (previously known as the Australian Underground Construction and Tunnelling Association) changed its name to include New Zealand.

Queensland

Queensland has been dominated by infrastructure projects based on the Lord Mayor Campbell Newman’s long term plan to improve travel in Brisbane, and recent completion of the Inner Northern Busway and the Tugun Bypass.

Brisbane NS Bypass

The big focus in Brisbane is currently the US$1.6bn plus North South Bypass Tunnel with a total length of 6.8km which includes 4.8km of dual twin lane tunnels.

RiverCity, consisting of ABN AMRO, Macqurie Bank, Leighton Contractors, Baulderstone Hornibrook and Bilfinger Berger, was awarded the contract to build and operate Brisbane’s North-South bypass tunnel under a public private partnership (PPP) contract with the Brisbane City Council with a 45 year concession.

There are two hard-rock, near 13m diameter TBMs on site, one commenced in December 2007, the second in April 2008. The double shielded machines commenced on the north side of the Brisbane River and are travelling south to finish at Woolloongabba by mid-2009

Boggo Road

Tunnelling at Boggo Road commenced in September 2007 and is being undertaken by an alliance between Queensland Transport, Thiess, SKM and United Group.

Tunnelling is proceeding with extreme care using a Voest Alpine AM105 roadheader beneath the heritage listed jail, built back in 1903, with canopy tubes and lattice girders being utilised to manage ground settlement as tunnel cover reduces to 5m.

When completed, the 430m long tunnel will connect the South East busway to the recently opened Eleanor Schonell Bridge.

Brisbane Airport Link

BrisConnections team of Thiess, John Holland and Macquarie has been named as the preferred consortium for the US$3.2bn plus Brisbane Airport Link – a 5km twin tube tunnel to the Airport, the 3km long Northern Busway road, half of which is in tunnel, and the Airport roundabout upgrade projects.

Work on the Airport link, including underground ramps, will total 11.8km and will be built using two TBMs and 11 roadheaders for completion in 2012.

The ground conditions consist of Brisbane Tuff, phylite and greywacke of the Neranleigh–Fernvale Formation and felspathic sandstone of the Aspley Formation with overlying alluvium.

Brisbane Northern Link

The Brisbane City Council’s planned Northern Link tunnel will burrow under some of Brisbane’s most expensive suburbs. The concept design plan for the 4.7km tunnel has been prepared by Sinclair Knight Merz and Connell Wagner.

A final design will not be done until the construction tender is announced late next year. The 5.5km road project is expected to open in 2014.

New South Wales

Following the financial problems of the Cross City Tunnel and Lane Cove Tunnel the construction of further road tunnels in Sydney such as the M4 East extension and the F3 to M2 connection has slowed.

However service tunnels and a huge Metro for Sydney continue to be developed.

City West Cable Tunnel

The City West Cable Tunnel passes below the Darling Harbour Exhibition Centre across Tumbalong Park to Sussex Street. It will carry 132kV electricity transmission feeder cables from Ultimo to the new City North Substation in the CBD. The tunnel being constructed by TBM is 1.6km in length, 3.75m in diameter and is located 20 to 45m below surface. Excavation will be primarily through Sydney Sandstone.

The US$42.8M contract awarded to Thiess commenced in April 2007 and is due to be completed in April 2010.

NW Rail Link

The NSW Government has proposed a US$10bn metro system to provide public transport for the NW of Sydney. Featuring 17 new, easy access stations, the North West Metro will run in 5.5m diameter TBM constructed twin tube tunnels for some 32km from Rouse Hill via Epping to the CBD. The first stage from Epping to the Hills Centre will be completed by 2015, with the entire line from Rouse Hill to the CBD to be completed by 2017. The metro project replaces the government’s 10-year-old plans for the north-west rail link, which was to make use of the existing heavy rail system.

Sydney Desalination Plant

Blue Water, a joint venture of John Holland and Veolia Water, has been contracted by Sydney Water to design, construct, operate and maintain the Sydney desalination plant for a price of some US$761M.

Water from the desalination plant at Kurnell will be pumped into Sydney’s water distribution system through a pipeline from Kurnell, across Botany Bay to Kyeemagh. Seawater will be pumped into the plant through a tunnel from the Tasman Sea. The water will be distributed to up to 1.5M people south of Sydney Harbour, to supplement their water supply.

The land portion of the pipeline will be laid using a number of methods, including open trench and trenchless construction. Microtunnelling will mainly be used in residential areas and to cross rivers, railways and major roads. The project start up was in mid 2007 for commissioning in 2010.

Victoria

Accidents in the Melbourne City Link tunnels have caused Vic Roads to develop new rules for road tunnels in Victoria just in time for the opening of the EastLink freeway. But this has not stopped planning for further road tunnelling projects to ease transport across Melbourne. The other two main projects currently underway in Victoria are the Bogong Hydro Plant and the North West Sewer Project. Both these projects are continuation of historic works. The Bogong Power Station was originally intended to be part of the overall hydroelectric development of the Kiewa Valley in Victoria, however, it was never built. The Northern Sewer Project is an extension of Melbourne’s North West Sewer commissioned in 1998.

Northern Sewer Project

John Holland was initially awarded the US$238M contract to build the first stage the Northern Sewer Project and then awarded the US$135.6M Stage 2 contract in September 2007. The project is to finish by mid 2012. Connell Wagner and design joint venture SKMJacobs are the Project Managers.

Stage 1 is a major 8km long deep tunnelled sewer connecting the existing system near Merri Creek to the northwestern sewer in Essendon and commenced in early August 2007. Geology is typically siltstone, with intrusions of basalt and alluvial soil deposits. Tunnelling is by two Herrenknecht EPBMs with eight shafts with maximum depth of 65m and 13m in diameter.

Stage 2 is a 4.5km long, deep tunnelled sewer joining the Stage 1 works at Coburg which commenced in late 2007. The sewer will have a cut diameter of 3m and a finished diameter of 1.8m and includes four major access shafts of up to 39m in depth and 10m in diameter. The tunnel alignment goes through high strength abrasive basalt to be excavated by hard rock shielded Robbins TBM, a section of Brighton group and alluvium is anticipated and a Herrenknecht EPBM will be used for this section.

The Robbins TBM will bore through basalt rock ranging from low strength to 270MPa. Muck cars will be hoisted up the shaft and dumped into a spoils bin for removal by rubber-tired vehicles. Launch of the TBM was scheduled as T&TI went to press.

Bogong Hydro Power Project

McConnell Dowell Constructors have been awarded a design and construction contract for the Bogong Hydro Power Project by AGL Southern Hydro in Victoria, in the largest hydropower project to be constructed in Australia in 25 years.

The scope of work consists of approximately 6km of 5m diameter headrace tunnel, two vertical shafts, a 1km steel-lined high pressure tunnel, a power station to house twin 70MW generators and a tailrace outfall into neighbouring Lake Guy

Bogong is scheduled to be fully commissioned by October 2009 and will generate 94,000MWh of emission free new renewable electricity each year thereby abating 122,000 tonnes of greenhouse gas emissions.

North Central City Corridor

The centerpieces of Sir Rod Eddington’s US$14bn blueprint for Melbourne’s transport are two new mega tunnels under Melbourne.

Sir Rod has called for construction of a road tunnel starting in the west, via one of two yet-to-be-selected routes, and finishing in Clifton Hill at the Eastern Freeway with no exit points to the CBD. His proposal for a new 17km rail tunnel would run from Footscray to Caulfield, with new stops at Parkville, the city, along St Kilda Road, and finishing in Caulfield.

Western Australia

Perth has just seen the completion of the Perth Metro Rail Project this year, the biggest tunnelling project ever in Western Australia with 700m of twin 7m diameter bored tunnel. However sewer tunnel projects continue with the Alkimos Wastewater Project.

Alkimos

The Alkimos Wastewater Scheme is a US$285.4M project to provide essential wastewater infrastructure for the northern suburbs of Perth. The Alliance contract was awarded to the Alkimos Water Alliance comprising Multiplex Engineering, Macmahon Contractors, Züblin (Australia) and the Water Corporation in early 2007.

The project includes a wastewater treatment plant built in an open cut of approx. 3M cubic metres volume and 5km of 2m diameter main sewers. The Quinns Main Sewer is being constructed using open cut and pipe jacking with 13 shafts up to 20m deep. The project also includes a 3.7km ocean outfall and a 1km tunnelled connection to the treatment plant using a Herrenknecht Dual Mode TBM.


Canopy installation on Brisbane’s Boggo Road Tunnel Segment erection on Brisbane’s North-South Tunnel View up the shaft on Sydney’s City West Cable Tunnel Fig 1 – Plan map of the ambitious $12.5bn North West Metro for Sydney, 32km of which will be in twin tube tunnel Breakthrough on Perth’s Metro Rail Project