Marine Ground Investigations

Overwater Ground Investigations

Causeway Geotech's personnel have a vast amount of experience in the design and execution of marine ground investigations.
Previous investigations have been carried out for port and harbour developments, bridges and outfall pipelines. In addition to carrying out overwater ground investigations, we have also carried out works directly relating to marine construction activities (drilling of blast holes for underwater excavations, installation of rock anchors and distressing wells within cofferdams).

We have conducted overwater ground investigations using a vast array of floating and static work platforms, including multicat workboats, floating pontoons, spud-leg and jack-up barges. We have experience in working in water of up to 25m depth, at sites including inshore estuaries and near shore wind farm sites. Our services range from seabed sediment sampling by grab sampling techniques – a rudimentary method used to obtain samples often used for contamination testing - right through to the drilling of inclined boreholes off specially configured jack-up platforms.

Overwater projects conducted

  • Harbour extension projects
  • Bridge projects
  • Ground investigation for pier and tower foundation design
  • De-stressing (pressure relief) wells for cofferdams
  • Marine outfall
  • Site investigation
  • Drilling of blast holes for construction
  • Energy park developments

Typical methodologies

  • Marine sediment sampling (for disposal at sea criteria analysis)
  • UXO clearance (magnetometer carried out with drilling using stainless steel casing)
  • Cable percussion boring, including specialist soft sediment sampling, in-situ vane tests, coupled with standard sampling and testing
  • Rotary drilling, by conventional and wireline coring techniques
  • Rotary percussive drilling
  • Environmental and geotechnical sampling
  • Packer testing
  • CPTs
  • In-situ pressuremeter testing in both soil and rock
  • Borehole geophysics (downhole logging by televiewer, etc.)

Other Marine Works

  • Underwater rock anchor installation off jack-up platform
  • Drilling of blast holes for underwater excavations (for foundation pits and outfall trenches)
  • Drilling and installation of destressing (pressure relief) wells within pre-installed cofferdams
  • Fissure grouting of highly fractured rock formations