NFM Technologies Completes First Yangtze River Crossing Tunnel in ChinaThe first of the two NFM Technologies slurry type tunnel boring machines, 11.38 m in diameter, has successfully crossed the Yangtze river in Wuhan, China breaking through the east tunnel on 19th January, 2008. The Yangtze river crossing consists of a twin 2-lane road tunnel. This tunnel is a major artery between the historical zone of the city and the Hankow business quarter. Visit www.nfm-technologies.com The geology of the Yangtze river bed comprises sand stratum, gravel, and shale rock. Of the total length of 5,049 metres excavated by the machine, 3,800 metres has been completed in critical geological conditions with confinement pressures approaching 7 bar. Under these conditions, the machine performed very well, achieving average progress of eight to ten metres per day and peak progress rates of 15 to 20 metres per day.The first tunnel has been completed without the need to change the cutting tools (disc cutters and drag bit) that equip the cutter heads since excavation began, which would have required hyperbaric interventions that would have been difficult at such pressures.The Yangtze river crossing tunnel had to face other challenges. Around the tunnel job site, there are different kinds of underground pipelines, which makes the tunnel construction more complicated. Other challenges are very strict requirements for surface settlement and soil deformation control and environmental protection. The project is implemented by the China Railway Tunnel Group. D2 Consult of Austria is consultant on the project. Two shafts have been constructed on both river banks and tunnelling was performed from the start shaft in the south to the exit shaft in the north. Visit www.d2-consult.co.atThe second machine, which is still working on the banks of the Yangtze, is expected to complete the second, west tunnel at the end of February. The tunnels are lined with precast concrete segments. Construction commenced in December 2004 and the entry in service of both tunnels is scheduled in August 2008. The project is on time and within schedule. The average daily traffic is expected to reach 50,000 vehicles, capable of dealing with around 15% of the daily volume of traffic across the river. Click here and here. Read E-News Weekly 20/2007, 29/2005, 50/2004, 18/2002 & 13/2002. 08/08.