Advancing toward the ocean and pursuing dreams in Qingdao. Recently, the Fourth Survey and Design Institute of CRCC (Tiesiyuan) won the bid for the engineering design of the Qingdao Jiaozhou Bay Second Subsea Tunnel, Asia's longest subsea highway tunnel, adding heavyweight credentials to its core 'underwater tunnel' brand.

　　The Jiaozhou Bay Second Subsea Tunnel crosses the central waters of Jiaozhou Bay, connecting Qingdao's main urban area in the east and the West Coast New Area in the west. The tunnel has a total length of 14.36 kilometers and adopts a three-bore layout consisting of two main-line tunnels plus an intermediate service tunnel. It is the world's largest subsea highway tunnel built by the mined method and the longest subsea highway tunnel in Asia.

　　In May 2017, Tiesiyuan won the bid for the feasibility study of the Jiaozhou Bay Second Subsea Tunnel project. Over more than four years, the institute's staff have consistently taken project optimization as their mission, continuously innovating their thinking and conducting refined comparisons of schemes. Faced with a series of world-class challenges—including crossing large-scale regional faults, passing beneath numerous important buildings and structures, limited reserved land for road construction, and ventilation and smoke exhaust for an ultra-long subsea tunnel—the engineering designers carried out repeated research and exploration. They also invited top industry experts on multiple occasions to 'diagnose and advise,' aiming to 'build a Chinese brand of subsea tunnels,' repeatedly studying and verifying the many 'firsts' involved in the project, and solving a series of extremely complex problems. The construction of the Jiaozhou Bay Second Subsea Tunnel is of major strategic significance for further promoting the integrated development around Jiaozhou Bay, enhancing the overall competitiveness of the Jiaodong Peninsula urban agglomeration, and building a world-class greater bay area. It is an important hub and engine for Qingdao's development as a key node of the national Maritime Silk Road, a new platform for 'Belt and Road' international cooperation, and a bridgehead for the Shanghai Cooperation Organization demonstration zone and opening-up.