Tuen Mun–Chek Lap Kok Link: an outstanding subsea tunnel project in Hong Kong

Abstract

The 4·5 km long northern subsea tunnel section of the new Tuen Mun–Chek Lap Kok Link in Hong Kong had to overcome challenging ground conditions, not least groundwater pressures of over 5 bar. Hard ground meant some 2000 disc cutters on the two 14 m diameter slurry tunnel boring machines needed changing during the drives, initially by professional divers kept in saturation conditions. Two robotic systems were later developed and installed on the tunnelling machines to do the job. Other innovations included pipe-jacking the 41 subsea cross-passages and creating a 500 m long, 43 m deep caterpillar-shaped cofferdam for a cut-and-cover section. This paper presents details of the innovative solutions used and lessons learned.