Highways Department
SCA 2020 Project owner (Public sector) - Merit Award
Practices
The Tuen Mun-Chek Lap Kok Link Northern Connection is a strategic link, which lies a sub-sea tunnel
of about 5km long crossing the Urmston Road. This is the first sub-sea tunnel in Hong Kong to use
TBM tunnelling method to prevent dredging and disposing of 11 million m3 of marine sediment. The
use of modular integrated construction in the submarine tunnel further makes the construction
process more sustainable.
Adopting TBMs to build the tunnels saved 11 million m3 of marine sediment from dredging and disposal, reduced impacton the environment and marine lives during construction. To excavate the tunnel, three TBMs ranging from 14m to 17.6m in diameter were deployed. The photo shows the largest TBM in the world at the time of construction.
Modular integrated construction was adopted in various structural elements of the submarine tunnel, including lining segments, overhead ventilation duct slabs, parapet structure with walkway slabs and services gallery. The latter, located at the space below the tunnel carriageway accommodates utilities such as water mains, fire mains, drainage pipes and telecommunication cables. The photo shows the installation of the service gallery.
Due to adverse rock formations, the world’s first 500m long caterpillar-shaped cofferdam was used in construction of the submarine tunnel. The caterpillar-shaped cofferdam makes use of the arch effect to retain the soil and water pressures. The innovative solution requires less ground treatment and eliminates the use of strutting, which maximises cost and construction efficiencies.