Abstract: In order to form a more comprehensive overview of the current development and technology trends of immersed tube tunnels in China, 36 immersed tube tunnel projects (including 20 built, 10 under construction, and 6 to be built as of the end of 2022) in China are analyzed in terms of tunnel distribution areas, tunnel structure types, and crosssectional forms, element prefabrication and application fields. Based on different application fields, typical immersed tube tunnel projects are introduced and the prospects of immersed tube tunnel technology are presented. Investigations indicate that: (1) The immersed tube tunnels in China are mainly constructed in South China (including Hong Kong and Macao), accounting for 75% of the total projects across the country. There are 21 immersed tube tunnels in Guangdong province, with most of them in Guangzhou (a total of 14). (2) Currently, the reinforced concrete structure is the main structure type of immersed tube tunnels in China (32 in total), most of which have rectangular sections. (3) For immersed tube tunnels in China, the element width is between 11.5 m and 55.46 m, and the element height ranges from 6.4 m to 11.4 m. With flexible crosssectional forms, the immersed tube tunnels are used as pedestrian tunnels, municipal (highway) tunnels, railway tunnels or combined highwayrailway tunnels. At present, most are used as the rivercrossing (undersea) municipal (highway) tunnels. (4) The longest immersed tube tunnel in China is 5.664 km and the maximum 〖JP2〗number of elements can reach 33, but the length of most immersed tube tunnels is less than 1 km and the number of elements is 3 to 10. (5) Elements are generally prefabricated in independent and axial dry docks. Among the tunnel projects under study, independent dry docks are adopted for 14 tunnels and axial dry docks for 9 tunnels.

Key words: immersed tube tunnel, structure type, crosssection type, segment prefabrication method