Hong Kong-Zhuhai-Macao Immersed Tunnel, China

The Pearl River Delta is one of the most densely populated areas in China. Its rapid growth has created a need for better infrastructure between the delta cities (Hong Kong, Shenzen, Guangzhou, Zhongshan, Zhuhai and Macao). This new infrastructure will create a megacity with more than 50 million people. 

The 50 kilometre Hong Kong–Zhuhai–Macao Fixed Link consists of several bridges, two artificial islands and six kilometres of immersed tunnel.

The tunnel section is the world's longest immersed tunnel for road traffic, comprising two bores with three lanes of traffic in each direction. 33 tunnel elements were built and installed – each one measuring up to 180 m x 38 m x 11 m and weighing 72,000 tons.  The tunnel elements were designed with the concrete structure providing water-tightness, similar to other long immersed tunnels such as the Øresund tunnel connecting Denmark and Sweden and the Busan Geoje tunnel in South Korea. 

The tunnel is scheduled to open in 2018.