Tuen Mun-Chek Lap Kok Link

The Tuen Mun–Chek Lap Kok Link project involves the construction of a twin-tube underwater road tunnel connecting the New Territories North to Lantau Island, where Hong Kong International Airport is located. The 4.2-kilometer tunnel was excavated at a depth of up to 50 meters below sea level in a high-pressure environment.

Each tube, with a diameter of approximately 14 meters, accommodates two lanes of traffic. The world's largest slurry pressure tunnel boring machine (17.63 meters in diameter!) was used to construct the first 600-meter section before being resized to accommodate the transition from a three-lane to a two-lane tunnel.

The operations required work in a hyperbaric environment and the use of technical innovations to ensure safety and limit human intervention.

The project also includes the construction of a 16.5-hectare offshore extension to accommodate the northern covered trench of the tunnel. This offshore platform is protected by approximately 2 kilometers of breakwaters and includes access structures and two ventilation buildings necessary for the operation of the infrastructure.

The work was completed with road improvements at the northern and southern ends of the route. Designed in accordance with strict environmental standards, the project incorporated measures to protect the marine environment, monitor water quality, manage waste, and limit pollution.

The complex forms an essential interface between the underwater infrastructure and the existing road network, contributing to the sustainable improvement of airport accessibility.