ARUP IS to carry out detailed design of China's first subsea tunnel, linking Xiamen Island to the mainland.
The 6km crossing, which forms part of the Xiamen East Corridor, is being designed in collaboration with China Communications Second Highway Survey and Wuhan Design & Research Institute. The client is the Road & Bridge Construction Investment Corporation of Xiamen.
Xiamen Island is served by two bridges but these are closed several times a year by typhoons. The new crossing will have two horseshoe-shaped running tunnels carrying three-lane carriageways and a central service tunnel.
Its 4.5km subsea section will be mainly through granite bedrock which has occasional fault lines. It will be constructed by drill and blast, said Arup director James Lui.
The remaining 1.5km passes through soil strata in shallow water areas.'We are looking at various options for ground treatment to allow the tunnel to be constructed there, ' Lui said.
'We are also looking at the possibility of cut and cover.'
Construction of the smaller diameter service tunnel gets under way this month. This will effectively form part of the site investigation for the main tunnels, on which construction is due to start in June 2005. It is scheduled to take four years.