Geological concepts are the technical terms used to describe the structure, composition and properties of the subsoil, such as rock types, soil layers, soil types and earth-related processes that are important for construction.
For any construction project, knowledge of the subsoil is indispensable. Geological concepts help engineers, architects and contractors to assess the ground correctly and choose the right type of foundation.
Important geological concepts
- Rock types: igneous rock (such as granite), sedimentary rock (sand, clay, limestone) and metamorphic rock (slate, marble).
- Soil layers: successive layers such as topsoil, sand, clay, peat and gravel, each with its own bearing capacity.
- Soil types: sand, clay, loam, silt and peat determine stability and water permeability.
- Groundwater level: the level at which the soil is saturated with water.
- Settlement: the compression of the soil under load.
Application
When designing a foundation, the soil structure is mapped through a cone penetration test or boring. Geological knowledge determines:
- What bearing capacity the soil has.
- At what depth a load-bearing layer lies.
- Whether there is a risk of settlement or water problems.
| Soil type | Bearing capacity | Water permeability |
|---|---|---|
| Sand | High | Good |
| Clay | Moderate | Poor |
| Peat | Low | Poor |
Related terms
- Soil mechanics
- Cone penetration test
- Foundation
- Soil
- Geodesy
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