The first EPBM to be used in Hong Kong, an 8.6m dia. NFM machine, is being assembled ready to start boring at the end of this month on WestRail’s 3.6km long Kwai Tsing Tunnels.
The US$246.7m Kwai Tsing Tunnels comprise two tunnels, namely the 1.8km long, 8.4m diameter Tsing Tsuen Tunnel and the 1.7km long, 13m wide, 9m high, horseshoe shaped Ha Kwai Chung Tunnel (plus a 0.1 km long cut+cover section). The Tsing Tsuen Tunnel will be an EPBM driven, twin-bore, single-track tunnel; the single-drive, twin-track Ha Kwai Chung Tunnel is currently being constructed by drill + blast and 60m has been excavated from the starting southern portal.
The Ha Kwai Chung Tunnel is being constructed at depths varying from 17m to 180m below ground through mainly fine to course grained granite. Approximately 600m of the Tsing Tsuen Tunnels run through soft material consisting of fill, marine deposit and alluvium, while the remainder runs through coarse grained granite.
The NFM EPBM, capable of working in open and closed mode, was designed and manufactured in France and fabricated in Shanghai. It was then shipped to Hong Kong for final assembly at the construction site.
Contractor Dragages–Zen Pacific JV won the design+ construct contract DB-320 in October 1998 and began work in June 1999.
EPBM excavation of the first tube will take 6.5 months, with another 5.5 months scheduled for the second; with a three month machine turnaround for the second drive.
The design engineer for the contract is Atkins China; the independent checking engineer is Ove Arup & Partners Hong Kong Ltd. Completion of the contract is scheduled for October 2003.
