Eagles Nest Tunnel

Leighton was the leader of a joint venture responsible for the construction of this major section of Route 8 linking Sha Tin in the New Territories with Kowloon West.

The major element of the project was the twin 2.1 kilometre long, three-lane Eagle’s Nest Tunnel. This included a 400 metre long adit joined to the main tunnels as part of the ventilation system. All tunnels were excavated by the drill and blast method, using six jumbo drilling machines.

Apart from the tunnels, the project also included:

• two portal buildings, one at each end of the main tunnel, plus a ventilation building at the entrance to the adit
• an administration building and maintenance workshop
• site formation works and slope works, including 400,000 cubic metres of cut and fill work and a major culvert and channel to divert the outflow of the Kowloon Byewash Reservoir
• roadworks, including a toll plaza with a subway and footbridge
• architectural finishes to the two portal buildings on the adjacent Sha Tin Heights tunnel
• all electrical and mechanical services for the Eagle’s Nest Tunnel, the Sha Tin Heights Tunnel and its portal buildings, the Tai Wai Tunnel and the noise enclosures in the adjacent Lai Chi Kok Viaduct contract
• extensive landscaping

Tunnel blasting was required to meet strict vibration limits within a 60 metre protection zone around various Water Supplies Department facilities, including a water treatment plant and a section of a water supply tunnel running just 20 to 30 metres beneath the tunnel.

In order to enable tunnelling and mucking operations to be carried out during extended working hours, various noise control measures were implemented, including the erection of extensive temporary noise barriers to shield nearby residential properties and the implementation of time limits on the operation of tunnelling equipment.