MTRC- Seabed Sounding & Sampling for IMT & WIT Immersed Tubes and Laboratory testing of marine deposits


  • Victoria Harbour, Hong Kong
  • Mass Transit Railway Corporation
  • EGS (Asia) Limited
  • GBFC Ltd.
  • 2010

Project Highlights

MTR Corporation Limited (MTR) requires hydrographic surveys over their immersed tube tunnels to collect necessary data for the planning of maintenance works. For each tunnel, the hydrographic survey consists of a bathymetric survey followed by sampling and laboratory testing of the marine deposit at 8 selected locations.

EGS (Asia) Limited is appointed by MTR to carry out the required hydrographic surveys over the following immersed tube tunnels:

  • Immersed tube tunnel between Tsim Sha Tsui and Wan Chai (IMT)
  • Immersed tube tunnel between West Kowloon Reclamation Area and Sheung Wan (WIT)


GBFC Ltd have been engaged to use the Diver-operated hammer jet vibrocorer for sediment sampling in this project. The diver-operated vibrocorer is a pneumatically driven light-weight vibrating corer designed for remote operation and is capable of obtaining up to 4m of 76mm diameter core in unconsolidated sediments in water depths where divers can work.

The specifications of the vibrocorer are list below

  • Drive Unit:
  • Weight:
  • Vibration frequency: Power Supply:
  • Core Barrels:
  • Core Bits & Catchers: Weight:
  • Pneumatically driven motors with bearing vibrators. 50kg.
  • 300 cycles/min
  • Compressed air
  • Irrigation tubing. 76mm or 75mm ID, wall thicknesses 2mm or 1.5mm
  • Hardened stainless steel bits with spring steel leaf catchers
  • Total weight core tube and vibrating head ~150kg