Which testing method is commonly used for determining the electrical resistivity of soil?

The Wenner Method is prominently used for determining the electrical resistivity of soil. This technique involves placing four equally spaced electrodes in a straight line within the ground, allowing for a precise measurement of resistivity. The arrangement of the electrodes minimizes the influence of contact resistance, ensuring that the resistance measured is primarily due to the soil itself.

When current is passed through the outer two electrodes, the voltage measured across the inner two electrodes can be used to calculate the resistivity of the soil using a specific formula. This method is particularly valued for its accuracy in various soil conditions, making it a preferred choice among professionals in the field of cathodic protection and geotechnical engineering.

While other methods such as the Four-Wire Method and the Surface Resistivity Test also measure resistivity, the Wenner Method specifically stands out in controlled environments for its straightforward application and reliable results directly correlated to soil resistivity.