Assessment of seismic cone penetration tests uncertainty: equipment set-up, processing, and interpretation workflows

Seismic cone penetration test (SCPT) is the dominant in situ testing technique for deriving small strain shear modulus (Gmax) for geotechnical site investigations. Representative and reliable Gmax determinations are particularly important for foundation design for offshore wind energy developments. SCPT data acquired using different systems often exhibit large scatter which increases the level of uncertainty and subsequently negatively impact foundation design. While various standards provide requirements and recommendations, these are not sufficient to ensure repeatability and accuracy of the measurements. A numerical study was performed using 3D finite element modelling of elastic wave propagation to determine the most favourable data processing workflow and interpretation. Uncertainty analysis was undertaken to identify those combinations that return the lowest uncertainties in the determination of Gmax. This paper presents and discusses the results and provides operational and technical recommendations for SCPT acquisition as well as data processing and interpretation.