Technical Visit to the Tuen Mun – Chek Lap Kok Link Northern Connection Sub-sea Tunnel Section (16 January 2016)
A technical visit to the Tuen Mun – Chek Lap Kok Link (TM-CLKL) Northern Connection Sub-sea Tunnel Section was held on 16 January 2016 with the participation of 23 persons.
The visit commenced with an introduction and a presentation of the project background given to the participants by the Highways Department of the Government of the Hong Kong Special Administrative Region (HKSAR) and the Resident Site Staff from AECOM Asia Co. Ltd.
The project involves the design and construction of the longest, largest and deepest sub-sea road tunnels in Hong Kong. The tunnel section is a twin tunnel approximately 5 km long between Tuen Mun and the Hong Kong-Zhuhai-Macao Bridge Hong Kong Boundary Crossing Facilities (HZMB HKBCF) with 56 cross passages at 100 metre intervals. The HK$18.2 billion contract is the largest single contract sum ever awarded by the Highways Department of HKSAR in Hong Kong.
At the northern portal, about 13.5 hectares of land has been reclaimed for the construction of a ventilation building, Tunnel Boring Machine (TBM) launching shaft, and cut and cover tunnels. The contractor proposed an alternative design which allowed the cut and cover tunnels to be constructed by the same TBM’s that would excavate beneath the sea. One of these approach tunnels had to be constructed using a 17.6 metre diameter TBM, which was subsequently reduced in size before the main sea crossing. Two identical mixshield TBMs of 14 metres diameter are being used to construct the road tunnels beneath the sea. At the southern end, there will be another ventilation building, twin tunnel, and associated features. The deepest part of the TM-CLKL sub-sea tunnels would be constructed at approximate 60 metres below sea level. Hyperbaric intervention facilities are provided for both TBM’s, including pressurized habitat and shuttle to allow saturation diving techniques for TBM cutterhead maintenance up to 6 Bar pressure.
Construction of the dual 2-lane road tunnels will be from the north to the south, and commenced in April 2015.
TM-CLKL Northern Connection Sub-sea Tunnel
To work under compressed air environment is one of the key challenges of the project. The project team proposed to use saturation diving technique for inspection and maintenance works of TBMs' cutter heads, which would maximise the health and safety conditions of workers, while enhancing work efficiency.
The hyperbaric saturation living habitat is located at the top of the TBM launching shaft constructed at the Northern Landfill. The under pressure shuttle is to be transferred from living habitat to the tunnel via the launching shaft.
Participants in the TBM Launching Shaft
Participants in the tunnel
Through this visit, participants had a better understanding of the TBM tunnelling works, construction of cross passages by pipe jacking method and the challenges in construction of subsea tunnels.
Mr Tim Leung (L), Council Member, presenting appreciation certificate and souvenirs to Highways Department’s Engineer, Ms Maggie Chan (middle), and the Chief Resident Engineer, Mr Andy Westmoreland (R)
On behalf of the IOM3 HK Branch, we would like to express our sincere thanks to Highways Department of HKSAR for the kind arrangements of the site visit.