Property modelling in the Thames Gateway Development Zone
Within the Thames Gateway Development Zone (TGDZ) a large proportion of planned development projects will necessitate construction on ground that contains:
- compressible soils,
- high groundwater levels, and
- potentially contaminated brownfield sites;
for which knowledge of the geology is crucial if sound decisions are to be made.
Rapid developments in information technology and the increasing collection and digitisation of geological data by the British Geological Survey allows geoscientists to produce meaningful 3D spatial models of the shallow subsurface in urban areas.
Attribution of the 3D model with geological property data
Using this new technology, it is possible to model and predict not only the type of rocks in the shallow subsurface, but also their engineering properties (rock strength, shrink-swell characteristics and compressibility) and hydrogeological properties (permeability, porosity, thickness of the unsaturated zone or the likelihood of perched water tables) by attribution of the 3D model with geological property data.
Property modelling in the Thames Gateway Development Zone (TGDZ)
To gain full value from the 3D geological model in the urban environment, attribution of the model with engineering geological and hydrological data is necessary.
The 3D model is attributed by assigning property values for each geological unit modelled (be that group, formation, member or bed).
Bulk attribution provides a way of visualising the property characteristics of each geological unit modelled and their spatial relationships.
The TGDZ model has been attributed with several datasets including lithostratigraphy, engineering geological classification, ground water productivity and maximum and minimum permeability.
The resulting attributed 3D model provides a platform whereby the integration and visualisation of data from many different sub-disciplines can be achieved. This allows the model to portray some of the natural heterogeneity of real geological systems.
The future
A considerable amount can be accomplished by bulk attribution of a geological model (as described above), for example an understanding can be gained about the general geotechnical, geological and hydrogeological ground conditions, such as thickness of the unsaturated zone or the presence of perched water tables or the depth to good foundations.
Current research is concentrating on the development of models that can display the full heterogeneity of a real geological system so that realistic modelling of near surface processes can be achieved.
References and further reading
Royse, K and Entwisle, D. 2010. Reply to discussion by J N Hutchinson on the paper 'Property attribution of 3D geological models in the Thames Gateway, London: new ways of visualizing geoscientific information. Bulletin of Engineering Geology and the Environment, 69, 157–158.
Royse, K R and Campbell, S D. 2009. Geoscience for Wonks. Geoscientist 19, 2.
Royse, K R, Rutter, H K and Entwisle, D C. 2009. Property attribution of 3D geological models in the Thames Gateway: New ways of visualising geoscientific information, Bulletin of Engineering Geology and the Environment 68, 1–16
Royse, K R. 2009. Utiliser et amenger l'espace souterrain Modelisation 3D du sous-sol pour les site des jeux olympiques 2021 a Londres. in Dossier special annee international de la planete terre. 10 enjeux des geosciences, pp. 111, ed. IYPE.
Royse, K R, Reeves, H J and Gibson, A R. 2008. The modelling and visualisation of digital geoscientific data as an aid to land-use planning in the urban environment, an example from the Thames Gateway. in Communicating Environmental Geoscience, pp. 89–106, eds. Liverman, D G E, Pereira, C & Marker, B.
Contact
For further information contact Dr Katherine Royse or Enquiries
