Channel tunnel headed undersea
Excavation work on the Jiaozhou Bay channel tunnel, the second of its kind in the country, is well underway in Qingdao and will begin to burrow under the seabed this year.
Scheduled to be open for traffic in 2011, two highway tunnels and an auxiliary passageway for maintenance will cross beneath Jiaozhou Bay to link Qingdao's satellite city Xuejiadao on west coast and Tuandao on the north coast of the bay.
Some 3,950 m of the 7,800 m tunnel will be under the sea floor. When completed, six lanes will accommodate vehicles at speeds of up to 80 km an hour.
The project broke ground in Xuejiadao at the end of 2006. When finished, the tunnels will enable a five-minute drive to the other side of the bay.
After a year of work, the two main tunnels have now reached 400 m in length.
"We are advancing smoothly with the project," said Gao Haidong, project chief of the China Railway 18th Construction Corp, one of the project's contractors.
"We can dig at around 10 m each day in loose geologic sites, while in the case of hard places, only 2 m a day," Gao added.
The digging is largely through solid rock, so current progress is from 2 to 10 m a day, he said.
Construction of the land portion will be completed in October, followed shortly by the onset of undersea excavation.
The tunnels will run through rock strata 70 m below the surface, built in compliance with top safety criteria set by State authorities. They are designed to withstand earthquakes of up to 7 degree on the Richter scale, experts said.
The 3.18 billion yuan project is financed by investors, government bonds and bank loans.
China's first channel tunnel is the 9 km Xiang'an tunnel, about 6 km of which is under water. The project started in late 2006 in Xiamen in east China's Fujian province and is expected to be put into use in 2009.
Five more undersea tunnels are reportedly on the drawing board to be built over the next two to three decades in Bohai Bay and Hangzhou Bay in east China and the Pearl River Estuary in south China.
(China Daily 04/02/2008 page24)
