Constructors from China Railway No.4 Engineering Group Co., Ltd. (CREC4) are making steady progresses in the main line’s undercut tunnel for its No 2 Bid in building the world’s largest submarine tunnel in Qingdao, Shandong Province.
The digging by builders from CREC4 Seventh Engineering Co., Ltd in the 2.9-kilometer-long underground tunnel in the No 2 Bid for the Jiaozhou Bay Second Tunnel progressed for 1,000 meters by October 25, 2023, fulfilling the annual construction target for this year ahead of schedule.
The Jiaozhou Bay Second Tunnel will be 17.38 kilometers long, marking a new milestone in China’s engineering construction. It will link Qingdao’s main urban areas with its West Coast New District and will be constructed through drilling and blasting. As the world’s largest submarine tunnel in size, it is also a submarine tunnel in China that will witness the highest water pressure for the tunnel shields and deepest burial depth for blasts.
The total length of the main line of the No 2 Bid section is 3.44 kilometers long, which includes 500 meters of open-cut tunnel and 2.9 kilometers of underground tunnel dug through drilling and blasting.
The Jiaozhou Bay Second Tunnel, as a key project in Qingdao during the 14th Five-Year Plan period (2021-25) and a major artery in its “six horizontal and nine vertical” transport corridors in the city proper, will help boost traffic on both banks of Jiaozhou Bay, bolster the integration in the Jiaozhou Bay rim regions and enhance the high-standard opening-up of Qingdao.