China completes the world's longest undersea tunnel

The 6.7km long underwater tunnel marked the successful conclusion of China's longest project to build a sea bridge over the world.

The 6.7km undersea tunnel section of the sea crossing bridge connecting Hong Kong, Zhuhai and Macao completed July 7, setting the longest and deepest record in the world, according to People.cn.

The biggest challenge in the construction of the tunnel is the coupling of giant underwater pipes. The tunnel is located at a depth of 48m below the Chau Giang estuary, made up of 33 pipeline sections with a 6,500-ton junction in the middle. Each pipe section weighs about 80,000 tons, equivalent to an aircraft carrier.

Sea bridge connecting Hong Kong, Chau Hai and Macao.

The complex of Y-shaped overpasses includes a 22.9km long bridge over the water, 6.7km undersea tunnel and two artificial islands to transport materials, while allowing large tankers to cross by.

The bridge runs from Zhuhai City, Guangdong Province, to Hong Kong and Macau , helping to reduce traffic time in the area from 4 hours to 30 minutes. This is also the longest sea crossing bridge in the world, expected to go into operation later this year after 7 years of construction.

Zhang Jinwen, the project director, said that the paving work would be completed in August if the weather was good and the tunnel construction would begin soon.

"The completion of the bridge will significantly alter the regional traffic structure on the west bank of the Pearl River," Chen Guanghan, an expert at the Guangdong Development Research Institute, Hong Kong and Macao of Zhongshan University. , comment.

China built a tunnel of 6.7 km under the sea.(Video: Xinhua).

1. China built the longest cross-sea bridge in the world