Rock & Alluvium, part of Van Elle, has installed its deepest continuous flight auger piles to date, reaching 40m, for the Bow Green development in East London. The record-depth CFA piles indicate challenging ground conditions and high load or settlement performance requirements typical of dense urban sites near the Thames. Contractors and designers may need to consider comparable pile lengths, rig capabilities and spoil management strategies for future high-rise or mixed-use schemes in similar London alluvial and made-ground profiles.

Helical piles are presented as displacement deep foundations that can be installed with small hydraulic drive heads on mini-excavators or skid steers, generating minimal spoil and vibration compared with driven piles. The FAQ addresses load capacity verification via torque correlation (e.g. kN-m per kN of capacity), corrosion protection options such as hot-dip galvanising and increased sacrificial thickness, and suitability in soft clays, fills, and below groundwater. Design is framed around ICC-ES AC358, with emphasis on tension, compression, and lateral performance for underpinning, boardwalks, and utility structures.

Settlement prediction in layered soils is shown to depend strongly on how vertical stress increments are computed, comparing classical Boussinesq-based methods with numerical analyses in Settle3, RS2, and RS3. The piece contrasts 1D influence-factor approaches against 2D/3D finite element and finite difference models that capture stiffness contrasts, non-linear behaviour, and complex load geometries. For practitioners, it signals when simple elastic solutions become overly conservative and when full numerical stress redistribution is needed to refine serviceability settlement estimates.