Swart, DuanDippenaar, Matthys Alois2025-04-242025-04-242025-05Swart, D., Dippenaar, M.A. Weathering profile of completely weathered rock from the Dullstroom Formation, South Africa. Bulletin of Engineering Geology and the Environment 84, 223 (2025). https://doi.org/10.1007/s10064-025-04224-z.1435-9529 (print)1435-9537 (online)10.1007/s10064-025-04224-zhttp://hdl.handle.net/2263/102220This study investigates the weathering profile of completely weathered rock derived from the Dullstroom Formation in South Africa. The research emphasizes the significance of the soil-rock interface, particularly the transition between completely weathered rock and residual soil, in understanding mechanical, chemical, and hydraulic behaviours. Field sampling and laboratory analyses, including particle size distribution, Atterberg limits, X-ray fluorescence (XRF), X-ray diffraction (XRD), and X-ray Computed Tomography (XRCT), were conducted. XRCT proved invaluable in visualizing pore geometry, density contrasts, and the persistence of relict rock structures in three dimensions. The findings highlight how structural prominence decreases with increasing weathering intensity, influencing compressibility and porosity. The compressibility of the material correlates better with chemical weathering indices than traditional geotechnical parameters like void ratio or dry density. These insights contribute to the geotechnical characterization of weathered rock profiles and propose structural prominence as a novel parameter for evaluating mechanical behaviour across weathering stages.en© The Author(s) 2025. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License.Weathering profileDullstroom Formation, South AfricaCompletely weathered rockPorosityXRCT scanX-ray computed tomography (XRCT)Relict rock structureStructural prominenceSDG-15: Life on landSDG-13: Climate actionArticle