Nov. 13-16, 2017, will see leading international specialists in the global tunneling sector attend the AFTES Congress in Paris, which will include a special one-day event on Nov. 15 dedicated to the ITA Tunneling Awards. Launched in 2015, the first two ITA Tunneling Awards events have attracted more than 450 attendees and 200 entries.
One of these highlights of the program is the presentation of the winners in the “Major Project of the Year” category, which includes project with a budget greater than €500 million. The finalists for the 2017 “Major Project of the Year” are:
• Tehran Metro (Iran): A high-speed project. One immense project to be mentioned is the extension of the Tehran Metro: from the southeast of Tehran, the line goes through the city center to end up in the northwest of the city. Line 6 of the Tehran Metro will be 31.2 km long with 27 stations. This tunnel project is one of the longest in Iran. Started in 2015, this “lightning-project” has ended a mere 22 months later, in 2017, and a special record was established with 800 m of tunnel excavation completed within a week. This huge construction project required 35 access tunnels to build the NATM part of the main tunnel and the volume of steel used in this project is 20 times greater than the steel used in the constructing the Eiffel Tower. As the line passes beneath city center, various instruments and processes were used to decrease the risks arising from surface/subsurface obstacles (24-floor building, bridges, other metro tunnels, aqueducts, etc.). Cost: €514.6 million.
• Qatar Rail Metro (Qatar): Tunneling under sensitive structures. Tunneling beneath city centers, beneath buildings and especially specific structures has emerged as an increasing concern in the tunneling industry. The Qatar Rail Metro is one good example of efficient management of mining under sensitive structures. The Doha Metro includes the construction of twin bored tunnels and 31 stations.
Planned to be operational in 2020, the elevated and at-grade rail network will be built in two phases. The first phase are the Gold, Red and Green Lines with the second phase including an additional Blue Line. Not only did the project see 20 TBMs burrow silently beneath the city without a hint of disruption to the population, but the twin-bore single track tunnels were constructed using EPB technology, in order to mitigate the risks related to surface settlements, collapse, rapid water ingress through karstic features, excavation under sensitive structures or below man-made sea water channels, with the application of face pressure. Cost: €16.2 billlion.
• Delhi Metro Phase 3 Expansion Networks (India): Safety. The Metro Phase 3 expansion project in Delhi is one of the most ambitious underground construction work for India as it comprises of 106 km of tunneling with 34 stations having to cope with numerous technical challenges such as unforeseen geological conditions and densely populated areas. For five years, and thanks to many safety initiatives, the accident occurrence rate has been reduced which has led to a Lost Time Injury Frequency rate (LTIFR) of less than 0.02 in Phase 3 compared to 0.19 in Phase 2. Internal monitoring through site inspections and safety management initiatives such as Safety Trainings, Weekly Site Safety Walk and Monthly Safety Review meetings, were organized. When operational, the project will reduce vehicle greenhouse emissions to approximately 3.1 million tons per year. Fuel consumption will be reduced to 141,353 thousand liters/year. Cost: €4.2 billion.
• Confederation LRT Line (Canada): a delicate excavation. The Confederation Line is a state-of-the-art LRT system and Ottawa’s largest transportation infrastructure project since the building of the Rideau Canal. The Confederation Line is a P3 project between the City of Ottawa and Rideau Transit Group (RTG) funded by the Canada Federal Government and the Province of Ontario. The tunnel spans 2.9 km, is on average 15 m below the surface and features three stations on the Confederation Line project – Lyon, Parliament and Rideau.
In all, the project comprises thirteen stations and a 12.5-km route, with 10 km running above ground and 2.5 km underground. Three stations are located underground in the new downtown tunnel. The main excavation challenge for Lyon and Parliament stations was the close proximity of the basements. The stations are 18 m wide in between buildings, 20 m apart. The construction process foresaw an excavation by stages in order to transfer the ground loads from the arch to the invert through the cavern support, avoiding the loads into the basements. Cost: €1.4 billion.
Organised by the French Association of Tunnels and Underground Space, the three-day AFTES Congress event will attract underground space sector specialists from around the world: experts, architects, civil engineers and city planners will promote the underground as the new frontier and generate ideas on how it can shape and enhance our future. It will take place at the Palais des Congrès (Porte Maillot, Paris), including technical conferences and jobsite visits organised around the central theme of “Underground Space: Our Wealth.” A one-day conference dedicated to “Building our Future” at La CIté de l’Architecture (Trocadéro, Paris) on Nov. 16.