The first immersed tube of the Shenzhen-Zhongshan Corridor sea channel was embedded on June 17 after 34 hours of undocking, transport, mooring, and installation, according to Guangdong Transport Group.

The tube measures 123.8 m (135 yd) in length, 46 m (50 yd) in width, 10.6 m (12 yd) in height, and 60,000 tons in weight. It has a displacement of a medium-sized aircraft carrier and was floated from a deep basin at Niutou Island Immersed-Tube Prefabrication Factory in Guishan Town of Zhuhai to the open waters of the Lingding Sea at 2 am June 16.

Vessels began dragging the tube to its mooring area at 6 am and arrived at 4 pm. The immersion lasted from 10:30 pm to 10 am the next day and CCCC First Harbor Engineering installed at the buried section of Western Artificial Island at 11:45 am Wednesday. 

Embedment [Photo provided by Guangdong Transport Group to Guanhai App]

During the process, the project team overcame numerous difficulties including shipping the tube 50 km (31 miles) across seven shipping lanes. Lingding Shipping Lane, for instance, sees daily throughput of more than 4,000 vessels. Moreover, how to realize an end-to-end connection in deep-seas within errors of 5 cm was also one of the most severe challenges.

Specially developed ships Yihang Jin'an 1, the world's first self-propelled vessel for dynamic positioning, tracking, transportation, immersion, and precise installation of immersed tubes, and Yihang Jinping 2, the world's largest vessel for foundation trench gravel leveling, were used to overcome those issues.

The 24-km (15-mile) Shenzhen-Zhongshan link serves as a significant Guangdong-Hong Kong-Macao Greater Bay Area sea channel listed in China's 13th Five-Year Plan (2016-20). Stretching across the Pearl River Estuary from Shenzhen's Airport Overpass in Bao'an District to Zhongshan's Hengmen Overpass, it is another world-level complex (after the Hong Kong-Zhuhai-Macao Bridge) that integrates two suspension bridges, two engineered islands, and a 6,845-m (7,486-yd) tunnel.

The dual eight-lane tunnel now under construction consists of 32 steel-shelled immersed tubes 165 m (180 yd) long, 46 m (50 yd) wide, and 10.6 m (12 yd) high. It is the longest and widest of its kind in the world with a section width of up to 55.46 m (61 yd).

Upon completion in 2024, the link will alleviate traffic pressure in the Guangdong transport network and boost connectivity between eastern and western banks of the Greater Bay Area. A trip from Zhongshan to Shenzhen will be cut from more than two hours down to 30 minutes.