BGS Civils: discontinuities
| Scale | 1:50 000 |
|---|---|
| Coverage | All of Great Britain |
| Format | GIS line and polygon data. (ESRI, MapInfo, others available by request.) |
| Price | 30p per km2 for commercial use. Subject to number of users, licence fee and data preparation fee. Product 1: BGS Civils bundle (all 8layers) £0.50 per km2 Product 2: BGS Civils individual layers £0.30 per km2 Product 3: BGS Civils web viewer (subscription service) £500 per layer for the first layer. £100 for each additional layers. Or, £1000 for all 8 layers. BGS Civils comprises 8 layers: bulking volume, corrosivity (ferrous), discontinuities, engineered fill, excavatability, strength, sulfate/sulfide, foundation conditions. All products are subject to number of users, licence fee and data preparation fee. |
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This theme provides information on the discontinutites in bedrock and superficial deposits as part of a suite of GIS layers for different engineering parameters.
The spatial model covers England, Scotland and Wales at 1:50 000 scale and is based upon bedrock and superficial geology from BGS Geology 50k.
Discontinuities within rocks and soils are an important factor in all engineering activities.
What are discontinuities?
For the purposes of this engineering theme in BGS Civils, discontinuities are defined as any break in the continuity of a rock mass that has the potential to have zero or very low tensile strength.
As such it includes all stratification planes (bedding, layering and lamination), all foliation planes (fissility, cleavage, banding) and all fractures (joints, faults, fissures) as defined in BS5930 and ISRM.
It will not include interfaces (other than stratification planes/depositional interfaces) and chemical-solution breaks (such as solution cavities) that are included within the BGS discontinuity classification system. No further reference shall be made to the BGS discontinuity classification scheme as it is not considered appropriate for engineering geology applications.
Classification
The discontinuity parameters proposed for attributing the BGS Civils: discontinuities dataset are:
- stratification planes: lamination, bedding and layering
- foliation: bedding plane fissility/slaty cleavage, lineation/linear schistosity, schistose foliation, gneissose foliation
- rock mass: massive, blocky, tabular, columnar and irregular
- additional discontinuities: fissured, sheared, sheet/exfoliation joints
As previously stated, not all stratification planes and foliation planes are mechanical discontinuities. However, it would not be possible to differentiate between those which are and those which are not at the scale proposed. As such, it is proposed that all potential discontinuities within the rock mass be described.
Contact
Contact Digital Data for more information.
