Publication record details

Title Application of near-surface geophysical data in GSI3D : case studies from Shelford and Talla Linnfoots
Ref no OR/08/068
Author Williams, John; Scheib, Andreas.
Year of publication 2008
Abstract This report describes work that was carried out as part of the 3D Soils project of the former Sustainable Soils Programme. The work involved the acquisition of geophysical field data alongside traditional site investigation techniques to aid in 3D geological modelling of the shallow sub-surface. The first part of the report introduces the various geophysical techniques applied during site investigations, followed by a best practice guide to georeferencing geophysical data. It then goes on to describe how this data can be used in support of model development in GSI3D (Geological Surveying and Investigation in 3D). This report can be consulted as a guide to how near-surface geophysics can be used as an aid to building site-scale soil-geology models using GSI3D, and suggests that work of this kind should be carried out using an integrated approach utilising appropriate geophysical techniques alongside standard geotechnical practices. Geophysical techniques have demonstrated that Sand and Gravel (SAGR) deposits at Shelford are laterally variable in terms of their distribution and morphology, and a 3 m drop in-filled with SAGR has been mapped in 3D along with siltstone beds along the valley slopes. Depth to the base of peat was identified using ground-truthed geophysical data at Talla Linnfoots, and demonstrates that the distribution and thickness of peat vary across the site. Information regarding the location of in-filled channels in the underlying glacial deposits has been used to add resolution to the 3D model and to suggest targets for further investigation. Using a combination of geophysical and geotechnical data in GSI3D enabled the construction of 3D models showing the distribution of soil horizons, superficial deposits and bedrock geology. Various soil series/horizons were related to their parent materials by analysing their distribution in relation to the superficial and bedrock geology.
Publisher British Geological Survey
Series Open Reports
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