Shanghai will build one of the largest tunnels in the world to link Pudong with Changxing Island beginning next year, a senior local engineer said yesterday during an international tunnel symposium in the city.

The 15.2-meter-diameter tunnel will be the largest shield-constructed tunnel in the world, the most common construction method for underwater tunnels, said Huang Jinyuan, of the Shanghai Urban Construction Design and Research Institute.

The new tunnel is part of a connection to Chongming Island that will cost 12.3 billion yuan (US$1.48 billion), officials said.

The connection will be a combination of a tunnel and bridge with a total distance of 25 kilometers from Pudong to Chongming via Changxing Island, officials said.

The 9-kilometer-long tunnel, which comprises two parallel tubes with a combined six lanes of traffic, will be built to link Wuhaogou in Pudong to Chang-xing Island. Then, a 10-kilometer-long bridge will be built to connect Changxing Island and Chongming Island.

Sitting at the mouth of the Yangtze River, Chongming Island is the third-largest island in China with a total area of 1,041 square kilometers.

The project is expected to take at least five years to complete.

The three-day symposium, which will end tomorrow, attracted more than 300 tunnel experts from home and abroad.

Andre Assis, president of the International Tunneling Association, told the gathering that Shanghai should be careful in choosing future subway construction sites to encourage private investment and keep ticket prices reasonable.

"The city should avoid central business streets to start a subway project so that it won't cause addition

The city government is planning to construct a total of 17 subway and light-rail lines in the city's downtown area by 2020.

(eastday.com November 10, 2003)