Resitivity testing utilizes the geophysical technique of electrical resistivity. Rocks provide a high resistance to electrical current whereas wet soils provide an easy passage for the current to flow from one probe to another. The further apart the probes are, the deeper the ground that can be penetrated. The technology allows us to provide detailed two-dimensional subsoil analyses.
This non-destructive technique has wide-ranging applications:
1. The assessment of subsoil conditions in the location and design of foundations (the equipment detects changes in the moisture content of soils and therefore the potential bearing capacity of individual units within the subsoil).
2. The assessment of subsoil conditions for potential instabilities such as clay layers, rock features and angular planar features. These analyses can be used in areas where piling, underpinning and ground-beam designs are required.
3. Locating features, such as broken drains, relating to subsidence and building instability.
4. Investigation of karst features in areas underlain by limestone. This is extremely important around Ireland where many areas are underlain by karstified limestone. This technique can be used to identify cavities and swallow holes in karstified limestone that can result in serious subsoil failure.
5. Assessment of subsoil conditions for the location of underground structures.
6. Investigation of groundwater movement especially where saline intrusion in coastal and estuarine areas is significant. Used for locating wells to access freshwater.
7. Assessment of subsoil conditions in the location of percolation areas.