ELECTRICAL RESISTIVITY SURVEY

Electrical resistivity surveys are based on the use of a multi-electrode array in measuring the electrical resistivities as a function of depth or position of the surveyed ground.

Wenner Four Point Resistivity Survey/ Vertical Electrical Sounding (VES)

This is virtually the most common test method used to measure soil resistivity for electrical grounding design. This method relies on the estimation of the electrical resistivity or conductivity of the medium. In this method, current and potential electrodes are retained along a straight line at the same relative spacing to each other, around a fixed central point. This technique presumes that as the current electrode separation increases, the current penetrates continuously deeper. The method is applicable when designing earthing system in electrical substations & determining corrosivity of soil while laying metallic pipes.

Electrical Resistivity Imaging (ERI)/Electrical Resistivity Tomography (ERT)

ERI/ERT is a survey method for imaging subsurface structures. It corresponds to a series of sequential electrical soundings. The images we obtain show us the distribution of the resistivities within the subsurface from a two-dimensional perspective.

Three-dimensional imaging has the additional advantage of resolving the geometry of complex objects (foundations, caves, cavities, etc) by correcting for topographic effects. The resultant effect of optimizing the survey geometry is the permission of the coverage of relatively large areas while maintaining the quality of the results.

• Electrical grounding system evaluation

• Soil corrosivity studies

• Rockhead profiling / Bedrock mapping

• Mapping of geological structures

• Cave detection and mapping

• Soil resistivity studies

• Disposal pit/Trench delineation

• Fault and fracture delineation

• Landfill investigations

• Pipeline leak detection

• Saltwater intrusion studies