Enhancing the Visualisation and Analysis of Geotechnical Properties. Examples from the 3D Volume Change Potential of UK Clay Soils

Ground shrinkage due to shrink–swell clay soils is the most damaging geohazard in the UK, costing the economy an estimated £3.4B over the past 10 years. The towns, cities and infrastructure most susceptible to this shrink–swell behaviour are found mainly in the southeast of the country. Ten of these clay-rich soils have been used in this study. The Volume Change Potential (VCP) of a soil is the relative change in volume to be expected with changes in soil moisture content and is reflected by shrinking and swelling of the ground. Variations in plasticity with area and with depth can be depicted using purely statistical methods. To construct a more representative model of spatial VCP variation in clay-rich formations a more sophisticated 3-D interpolation is required, such as lithofacies modelling which can be used to produce multiple realisations of the variation of parameters, such as the lithology, across a domain where there is an abundance of XYZ data from boreholes or point samples. Virtalis GeoVisionary provides a means of viewing the lithofacies type generated data in a fully immersive 3-D environment. Similar visualisation can be carried out against many environmental parameters and geoscience datasets such as borehole, geophysical data, point clouds, CAD models etc. Voxel models are easily imported and are able to be visualised in their ’true’ spatial position, overlying geology or standard maps. The Geosure Shrink–Swell 3D dataset, created using Esri ArcGIS, provides a regional susceptibility model of potential shrink–swell hazard in the London and Thames Valley area. 2-D representations based on statistical analyses show general trends; but with large amounts of data unevenly spread over a wide area, the detail is lost. 3-D models, such as those created using voxelated facies techniques, provide a seamless interpolation and deliver a visualization of VCP that can be interpreted across a variety of depths.