Geotechnical Engineering

Offshore Site Investigations  

OWC is very experienced at offshore wind farm Site Investigation (SI) management, with staff who have managed many SIs over the last ten years.  

There are two main types of offshore surveys offered: 

• Geotechnical surveys (invasive surveys). Physically interfering with the seabed and soil layers beneath to capture physical properties of soils at the site: CPT, SPT, Sampling 
• Geophysical surveys (non-invasive). Mapping the seabed (bathymetry), mapping soil layers beneath the seabed, and identifying seabed features / physical hazards.  

OWC’s site investigation services include: 

• Running tender competitions, scoping and contract management, project management, data interpretation & report, soil models for foundation/cable design, and provision of client representatives.  
• Use of live SI methodology tool (i.e. calculating the length of borehole required as the ground information is gathered, ensuring boreholes are economically sized) for which we were finalists at the Ground Engineering 2015 awards.  

Geotechnical Design  

• Our team have developed ground models for the world’s largest and most complicated offshore wind farms.  
• Ground Modelling & Geotechnical Interpretation: Identify engineering units, assess ground behaviour, develop geotechnical design parameters, development of design soil models, identify ground risks and assess ground variability.  

Foundation Design and Installation Analysis  

• Our geotechnical engineers have designed over 500 offshore wind farm foundations.  
• Foundation Design:  
  • The Foundation Design includes the selection of geotechnical parameters, development of design soil models and finite element  
  • We have designed monopiles, jacket piles, gravity bases, mat foundations, ground anchors and suction caissons.  
• Foundation Installation Analysis include:  
  • Pile driveability assessments, Site supervision during foundation installation, Pile driving-induced fatigue analysis, seabed preparation advice, mud mat design  

Cable Route Analysis and Planning  

We have wide-ranging experience in the design and management of cable routes:  

We ensure the effective protection of the cable system throughout its design life with our in-house team of cable experts and geotechnical specialists, including review information such as SI, bathymetry, seabed mobility and other hazards to prepare cable burial risk assessments (CBRA) and assess the expected performance of available installation tools.  

Leg Penetration Analyses  

Extensive experience – worldwide in jack-up leg penetration prediction, using the latest codes and standards, considering layered soils and identifying risks such as rapid leg penetration, punch through and scour. These are then used for Site-Specific Assessments.