Horizontal Directional Drilling (HDD) works at Marske-by-the-Sea were being undertaken for 3 x 1000m long 300mm to 600mm diameter bores for landfall for Sofia Offshore Windfarm cables. The site was very constrained meaning that there was no room to realign the cable route, if the HDD bores failed. Careful attention and supervision of the HDD works was required to mitigate a serious project risk.
GCG was commissioned by Sofia OWF to serve as consultant geotechnical, HDD, drilling and drilling fluid specialists. We were to advice in respect of the HDD work and to provide site support as part of Sofia’s on-site team in the day-to-day dealings with the specialist HDD Contractor and their advisers. GCG’s scope included careful review of the ground conditions, site drilling works, drilling mud and drilling pressure information, and to advise Sofia on the contractor’s proposals including the full implications of risks and opportunities for the project and our client. We also collated lessons learnt information and prepared daily site reports while on site. Many problems occurred during construction of the first HDD bore and its marine pit, which we supported the client with. As a result of these issues, only one of the 3 bores was completed in the 2022 construction season, with the remainder planned for 2023.