OR/15/065 Technical information
| Entwisle, D, Lee, K A, and Lawley, R S. 2015. User guide for ‘BGS Civils’ - a suite of engineering properties datasets. British Geological Survey Internal Report, OR/15/065. |
Definitions
The description and classification of engineering strength depends on the type of deposit. In engineering geology, earth materials are split into two groups, ‘soils’ and ‘rocks’ as given below:
- Soil is an aggregate of mineral grains or organic material that can be separated by such gentle means as agitation in water. Their behaviour is determined by the particulate nature, specifically the particle size, particle shape, particle mineralogy, water content and material density. The mass properties are largely influenced by its material characteristics. The principal soil types are clay, silt (fine soils) sand, gravel (coarse soils) cobble and boulder (very coarse soils). Whether the soil is classified principally as fine or coarse is dependent upon the behaviour of the material as defined by simple hand tests that can be carried out in the field and not on particle size determinations. Discontinuities, such as fissure and shears affect the mass strength of some soils, primarily fine soils.
- Rock is an aggregation of minerals connected by strong and permanent forces. The behaviour of the rock material depends on the material characteristics. The behaviour of the rock mass depends on a combination of the material characteristics and the discontinuities (including spacing, roughness, persistence, filling, orientation and the number of sets).
How the data was created
The lithostratigraphy and lithology type and variability are implicitly classified in the BGS Lexicon (LEX) and Rock Classification Scheme (RCS) for each LEX-RCS code, and the individual property such as minimum/maximum and typical strength parameters/values have been determined for all LEX-RCS codes.
Data was collated and interpreted from a number of different sources currently held by BGS. The primary datasets used for the Engineering Properties dataset GIS are:
- Parent Material Map V6 dataset;
- BGS National Geotechnical Properties Database;
- BGS Lexicon of Named Rock Units;
- BGS Map Sheet Explanations;
- BGS Sheet Memoirs;
- BGS Geoscience Imagebase;
- BGS and Geological Society Regional Guides;
- BGS Urban Planning Reports (Smith and Ellison 1999[1]);
- BGS Engineering Geology Formation Study Reports;
- Site Investigation Records and Borehole Scans held in BGS archives;
- BRITPITS (an abbreviation of British Pits, Cameron 2011[2]).
The classifications for each LEX-RCS code and property are mostly based on those used by industry where available or from the literature. Bulking factor values were assessed using the characteristics from the literature. These included values from the United States of America (Church et al., 1981[3], Hartman 1992[4]), the UK (Horner 1988[5]) and web resources such as the Engineering Tool Box, Durham University (1997)[6] and Mal January’s site (january.id.au). Spatial distribution of the source information is shown in Appendix 8 - Distribution of source data.
References
- ↑ SMITH, A, and ELLISON, R A. 1999. Applied geological maps for planning and development: a review of examples from England and Wales. Quarterly Journal of Engineering Geology, 32, S1–44.
- ↑ CAMERON, D G. 2011. User guide for the BritPits dataset. British Geological Survey Open File Report OR/11/07. British Geological Survey, Keyworth, Nottingham. 27pp. https://nora.nerc.ac.uk/14162/
- ↑ CHURCH, H K. 1981. Excavation Hand book. MacGraw-Hill, New York City, New York, USA.
- ↑ HARTMAN, H L. (ed). 1992. Society for mining, metallurgy and exploration (SME) Mining Engineering Handbook, 2nd edition. Volume 2. Society for mining, metallurgy and exploration (SME), Littlejohn, Colorado, USA.
- ↑ HORNER, P C. 1988. Earthworks. ICE Works construction Guide, 2nd edition. Thomas Telford. London, UK. 62pp.
- ↑ DURHAM UNIVERSITY. 1997. Earthworks.https://www.dur.ac.uk/~des0www4/cal/roads/earthwk/earthwk.html