Tseung Kwan O submarine cable: relocating the beach manhole
Moving the beach manhole where an international submarine cable comes ashore, using precast units, underwater pipework and grout placed from a floating platform.
- Year
- 2012
- Client
- NEC
- Location
- Tseung Kwan O, New Territories
- Status
- Completed
- Category
- Underwater & marine
Where a submarine cable comes ashore it runs into a beach manhole, half in and half out of the sea. At Tseung Kwan O the manhole had to be moved, which meant building a new one in the tidal zone.
Five stages
- Remove the armour rock and excavate.
- Level the bed and place precast units of 9 and 13 tonnes.
- Install galvanised-iron cable pipes underwater.
- Fix steel formwork.
- Grout with concrete pumped from a truck on shore through pipes laid across a floating platform.
A silt curtain on floating buoys, weighted with geotextile, kept sediment inside the works area. We also prepared the hoarding design report for the shore side.
Drawings
