Borehole Drilling

Deep boreholes to investigate and assess ground CONDITIONS adjacent to the shoreline

On many coastal and marine projects, effective investigation of the ground beneath the shallow water zone can be particularly problematic. The nearshore zone is generally considered to be the area underwater with a maximum water depth of around 18m to 20m. 

In the nearshore zone, specialist jack-up platforms and other static access platforms can be used to place drilling equipment above sea-level, so that the seabed and deeper ground conditions can be investigated. In greater water depths, floating platforms and investigation vessels must be used, as jack-up equipment generally becomes impractical. 

The drilling of exploration boreholes is one of the most detailed and thorough means of investigating the ground strata, potentially to significant depth. When used in combination with other complementary investigation techniques, borehole drilling provides the necessary data to help the project team assess geotechnical risk, define an appropriate ground model, determine relevant design parameters and develop optimised solutions. 

Some key advantages of nearshore borehole drilling include:

• Samples are obtained from significant depth for visual inspection and testing; 
• Overlying competent material can be penetrated to assess the nature of underlying less competent strata; and
• A number of different tests can be conducted in the borehole to help assess the in-situ properties of the ground. 

The major limitation of borehole exploration (and particularly nearshore overwater investigation) is the relatively high cost for each borehole. To ensure the borehole work is cost-effective, it is essential that the location, depth and testing regime are well-planned and optimised to meet project requirements and anticipated ground conditions.  

Our CMW Geosciences team combines nearshore drilling experience from Engineering Geologists and Geotechnical Engineers to plan, scope, execute and log overwater borehole drilling and in-situ testing - to help maximise the quality of the data obtained and ensure relevance to project outcomes. 

As CMW Geosciences has extensive experience in complementary ground investigation techniques such as CPT probes, geophysics, grab sampling and vibro-driver sample recovery, we can scope a relevant investigation programme to ensure maximum cost-effectiveness of the nearshore borehole drilling work. 

If you'd like more information on how our borehole drilling services can assist your project, please reach out to us.