Projects & proof
Subsea pile installation solutions
Drilled and grouted foundation piles installed from a floating vessel, vertical or raked, in hard rock or unstable soft ground.
Installing foundation piles and anchors offshore is hard where the seabed is rock, where the ground is too soft to hold a bore or where the water is too deep for a jack-up to stand or a hammer to be practical. Our subsea pile installation approach answers all three by drilling the pile in from a dynamically-positioned geotechnical drilling vessel and grouting it in place, bringing the precision and ground-versatility of drilled foundations to locations that previously ruled them out. It is the pile-installation application of our large diameter drilling capability.
The method
A seabed frame is landed to react loads and guide and clamp the string. In hard ground we drill a cased rock socket and install the pile into it; in soft ground we pin the pile to the bottom-hole assembly and install it as the hole is drilled, under-reaming so the bit passes through. In both cases the pile is clamped by the seabed frame and grouted in place through a grouting-capable bit guide. Spoil is cleared by an airlift / reverse-circulation system sized for the duty.
Why it works where other methods don’t
- Water depth beyond jack-ups and hammers – working from a floating vessel reaches depths a jack-up cannot, and where driven piling is impractical.
- Both hard and soft ground – cased open hole for rock, drill-and-install for sands, gravels and clays, so a single system covers difficult, mixed ground.
- Vertical and raked piles – the method handles both, suiting jacket and anchor foundations as well as monopile-scale work.
- Weather-window resilience – a cased open hole can be left on the seabed and returned to, so weather downtime doesn’t mean losing the hole.
- Single-party accountability – drilling, handling, spoil removal, grouting and controls are designed and integrated as one system, commissioned by the people who designed it.
It is directly relevant to offshore wind, fixed and floating and to marine construction more broadly, where foundation certainty in difficult ground is what de-risks a programme.