How many undersea tunnels are there in China?

There are dozens of undersea tunnels in China. Cross-harbour tunnel is a technical project to build a traffic pipeline under the seabed of straits, bays and estuaries to connect with land traffic. Submarine tunnels are generally divided into two types: submarine surface and submarine stratum, and their construction methods are different. The cross-harbour tunnel does not hinder the navigation of ships on the water and is not affected by meteorological conditions such as strong winds and fog. World-famous subsea tunnels include the Japanese Han Qing Tunnel and the Anglo-French Channel Tunnel.

More than 20 subsea tunnels have been built or planned in the world, mainly distributed in Japan, the United States, Western Europe, China and other regions. In terms of project scale and modernization, the most representative subsea tunnel projects in the world today are the Anglo-French subsea tunnel, the Qinghai-Xinjiang tunnel and the Japanese Ma Haixia tunnel.

China Cross-Harbour Tunnel: Xiamen Xiang 'an Cross-Harbour Tunnel, with a total length of 8.695 kilometers, reaches the opposite end of the mainland from Xiamen Island. 20 10 on April 26th, the first subsea tunnel in Chinese mainland was completed and opened to traffic. Qingdao Jiaozhou Bay Tunnel is the second subsea tunnel in Chinese mainland, the longest subsea tunnel in China and the third in the world. The total length of the tunnel and its wiring project is 9.47 kilometers, of which the tunnel length is 7.808 kilometers.

The subsea tunnel of Hong Kong-Zhuhai-Macao Bridge consists of 33 immersed tubes, including 28 straight immersed tubes and 5 deflection tubes, with a total length of 5,664 meters. It is the first offshore immersed tunnel in China, the longest highway immersed tunnel in the world, and the only deep-buried immersed tunnel.