Methodology
| Name | Category | Description |
|---|---|---|
| Shrink-Swell Clays | Ground Stability | Shrinking and swelling of the ground (often reported as subsidence) is one of the most damaging geohazards in Britain today. This ‘shrink–swell’ behaviour is controlled by the type and amount of clay in the soil and by seasonal changes, related to rainfall and local drainage, in the soil moisture content. |
| Dissolution of Soluble Rocks | Ground Stability | Ground dissolution occurs when certain types of rocks, containing layers of soluble material, get wet and the soluble material dissolves. This can cause underground cavities to develop. These cavities reduce support to the ground above and can lead to a collapse of overlying rocks. The Dissolution of Soluble Rocks dataset (procured from BGS GeoSure data product) uses a number of datasets in its creation. These include: • geology (bedrock, superficial, artificial, mass movement) • digital terrain model • superficial deposits thickness model • karstic/non-karstic geology • glacial limits • superficial permeability |
| Compressible Ground | Ground Stability | Some types of ground may contain layers of very soft materials like clay or peat. These may compress if loaded by overlying structures or if the groundwater level changes, potentially resulting in depression of the ground and disturbance of foundations. |
| Collapsible Deposits | Ground Stability | If the material below a building collapses, it may cause the building foundations to rapidly subside. If the ground collapses unevenly, the resulting damage may be more severe than that caused by a uniform collapse. |
| Landslides | Ground Stability | Landslides occur ultimately due to the effect of gravity, although other factors can all contribute to the overall stability of a slope. Landslides are commonly divided into four categories: falls, topples, slides or flows. |