China has inaugurated the country's longest underwater tunnel under Lake Taihu in Jiangsu. Spanning 10.79 kilometers with six lanes, it connects the highways of Suzhou, Wuxi, and Changzhou, alleviating traffic in a key area near Shanghai. Its construction cost 1.23 billion euros and took nearly four years, using over two million cubic meters of concrete on a bed of clayey silt that required working in dry conditions with cofferdams.
Engineering on mud: how a six-lane tunnel was built in Lake Taihu 🚧
The biggest challenge was the lake's clayey silt bed, which required a system of cofferdams to divert water and excavate in dry conditions. The tunnel is 17.45 meters wide and required over two million cubic meters of concrete. Construction began in 2018 and finished in nearly four years. The structure is part of the highway connecting Shanghai with Nanjing, in a high-traffic region. The technical solution made it possible to overcome unstable terrain unprecedented in the area.
LED lights: the visual therapy that keeps you from falling asleep at the wheel 💡
To combat driver fatigue, the tunnel ceiling features LED lights that change color. So, if you're driving at 80 km/h under Lake Taihu, don't fall asleep: enjoy the aquatic neon show. Of course, the trick has its ironic side: the same tunnel that spares you traffic jams offers you a disco to keep you awake. Because, naturally, driving under a lake was already boring without a bit of psychedelia.