Dynamic image analysis of coarse soil in an offshore geotechnical laboratory

Dynamic image analysis of soil provides detailed information on particle size distribution and particle shape. The test method is covered by the International Organization for Standardization (ISO), with a first edition of standard ISO 13322-2 published in 2006 and a second edition in 2021. This paper presents procedures and ancillary apparatus for use of dynamic image analysis in a geotechnical laboratory subject to vessel movement at sea. Vessel movement caused by wind and waves may have an impact on various measurements involved in acquiring particle size distribution and particle shape parameters using dynamic image analysis. Possible impact of vessel movement on such measurements performed offshore is discussed in this paper. The focus is on a verification programme which was carried out to assess results of dynamic image analyses performed in various sea states. Results of the verification programme showed that dynamic image analysis can be performed up to the workability limits of a vessel if the apparatus is judiciously positioned on the vessel.