16th Young Geotechnical Professionals Conference (16YGCP) Cairns, 2026
Utility-scale solar farms typically involve large site footprints and lightweight infrastructure supported by shallow foundations, including driven steel piles and shallow pad foundations. Consequently, geotechnical investigations are generally shallow and spatially sparse relative to the scale of the development. This creates challenges for 3D engineering geological modelling, as shallow models are highly sensitive to coordinate and elevation errors, data gaps, and interpolation artifacts. This paper presents a practical workflow for developing preliminary 3D engineering geological models for solar farm sites using Leapfrog Works. The workflow comprises four stages: site investigation strategy and data quality assurance; geological model development; model validation and generation of deliverables; and derivation of geotechnical parameters. The paper highlights that a robust model cannot rely on software interpolation alone. Engineering judgement is required to ensure that modelled surfaces reflect the conceptual geological understanding at the site rather than mathematical artifacts. The workflow is demonstrated through two New Zealand solar farm case studies: Kōwhai Park and Bunnthorpe Energy Park. The paper concludes by qualitatively evaluating the benefits and limitations of 3D modelling for solar farm design.
