Page 8 - TunnelTalk Annual Review 2012

the Chilean entrance, located in Saladillo at 1,536m above sea level.
Upon completion of the two access adits, excavation will begin from each portal to complete the first tunnel in its entirety. Attention will then be turned to excavation of the parallel tunnel. At the same time, drill+blast connections to technical caverns and access tunnels to underground stations will be completed.
The final front of excavation is that of the 2,393m-high Punta de Vacas entrance in Argentina, which will complete the last section of the first tube. Once the excavations of these various sections are finished, the final lining in drill+blast excavations will be completed.
Normally the rarefied air at such altitudes can be problematic for the ventilation systems during operation, but not this time. According to Posse, “the height difference between the two tunnel portals makes for a 2% gradient. This gives a chimney effect. There will always be a wind blowing through the tunnel. Furthermore we will only use electric trains, keeping air pollution to a minimum.”
“We expect the first tunnel to be completed in ten years,” he explained. “We will operate two types of 750m-long trains. The first a roll-on-roll-off system for 30 trucks, and the second a freight train with a cargo capacity of 1,500 tonne.”
In stage two of the project, double track railways to and from the tunnel on both sides will be constructed, increasing capacity further. The second tube will be bored during the third and last stage, after which passenger trains will be added to the service (Fig 3).
Despite having just one tube during the first two stages of operation, Posse said, tunnel equipment, railway systems and rolling stock are designed in order to prevent any possible risk. “The trains will have three locomotives, any of which can continue at 8km/hr for 15 minutes, long enough to ensure a safe exit from the tunnel in an emergency. We will also install heat detectors at the tunnel portals for both the cargo and rolling stock.” Posse added that Corporación América is working on an alliance programme with the Massachusetts Institute of Technology (MIT) to develop a system based on nanotechnology that can detect smoke minutes before a conventional detector.
The US$3.5 billion Bioceánico Aconcagua is a fully private initiative. The Corporación América JV will operate the tunnel, earning its return on investment via freight charges. “We believe the location of the link is so strategic, and the volume potential so great, that public funds from the Governments will not be needed. The bi-national commission will provide the loan guarantees, but no taxpayer money will be used.” n
References
• Andes link a priority for Chile-Argentina- Brazil - TunnelTalk, December 2011
• Final finish for Gotthard Baseline excavation - TunnelTalk, March 2011
• Reflections on the UK Channel Tunnel - TunnelTalk, December 2010
Prequalifiers called for
Fehmarn sea link
Femern A/S News Release
Fig 1. Standard element tunnel, Fehmarn immersed tube
Fig 2. Special element tunnel, Fehmarn immersed tube
Procurement of the €5.5 billion Fehmarn immersed tube road and railway tunnel between Denmark and Germany took a major step forward in late 2012 with prequalification calls for the main works. By the 18 January 2013 deadline 24 companies organised into nine joint ventures successfully applied for prequalification. The nine groups comprised companies from Denmark, Germany, Italy, Spain, the Netherlands, Belgium, France, South Korea, the UK and the USA.
Following evaluation, Femern A/S will decide which prequalified companies will be invited to submit bids.
There are four civil engineering contracts for the coast-to-coast link:
• Dredging of the seabed and land
reclamation;
• Construction of the northern section
of the tunnel;
• Construction of the southern section
of the tunnel, and;
• Construction of the portal structures,
ramps and associated land facilities
Steen Lykke, Femern A/S Technical Director, said: “Once we have announced the prequalified companies in the Spring of 2013, the tender process will begin.”
Final project approval will be effected by the Danish Parliament’s adoption of a Construction Act by the end of 2014. In Germany it is expected that the authorities will approve the project in 2015.
Once constructed, the Femarnbelt Link, at just under 18km long, will be the world’s longest immersed tube crossing. About 15.5 million m3 of dredging is needed to form the trench at up to 43m below sea level. A planned 89 elements of 217m long x 8.9m high x 42.2m wide and weighing 73,500 tonne each will carry the road and rail link across the strait with 10 special elements placed at 1.8km intervals to house M&E equipment (Figs 1 and 2). Each tunnel contract is to include approximately 40 standard elements and five specials.
The construction period is expected to take six-and-a-half years, with a start date planned for 2015.
The client, Femern A/S, is anticipating up to six prequalified tenders for each contract.
A two-stage tender process is due to get under way in the middle of 2013 with awards for the design-build contracts anticipated by about mid-2015.
The tender process comprises two formal stages. Stage 1 is the technical and administrative submission followed by formal competitive process discussions. Stage 2 will see technical points updated and finalised for the tender documents and prices will be included.
Submissions can include design variations, “providing they comply with the Stage 1 and Stage 2 tender documents,” according to Lykke.
Partial repayment of bid preparation costs to unsuccessful tenderers is expected, subject to completing the tender process with compliant bids.
In the meantime, a consortium of RINA Services of Italy and SINTEF of Norway was selected for the contract to assess the design and planning of the tunnel’s rail system as well as all Femern A/S rail safety and risk management strategies.
Key design features that enabled a long tunnel solution over a bridge alternative included the possible use of longitudinal ventilation which avoided the need for an artificial island, and the adoption of special elements with deeper basements to house of the M&E equipment.
Following construction, the €5.5 billion (2008 prices) strategic transport link between mainland Europe and Scandinavia is planned to come into service by the end of 2021. n
References
• TBM tunnel considered for Fehmarn sea link - TunnelTalk, December 2011
• Innovations for the Fehmarnbelt tunnel option - TunnelTalk, May 2010
• Political backing to Denmark-Germany link - TunnelTalk, February 2011
• Cost comparison for Femarnbelt link options - TunnelTalk, November 2010
• Deep geological data on Fehmarn Link - TunnelTalk, May 2011
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