Soil Resistivity - Probe Depth
Soil Resistivity - Probe Depth
(OP)
Has anyone seen references on the effect of probe depth vs probe spacing using the Wenner 4 point method. It is easy to see statements that spacing to probe depth should be 10 or 20 to 1, and formulae are available when spacing is not much greater than probe depth. However, exact backup is not easy to find, and I am thinking about empirical as well as analytical observations. If it was 1 metre spacing and 1 metre depth, what would happen and why? That is what I am trying to find out. Having been presented with such data, I am trying to assess if it is useful.






RE: Soil Resistivity - Probe Depth
RE: Soil Resistivity - Probe Depth
RE: Soil Resistivity - Probe Depth
RE: Soil Resistivity - Probe Depth
RE: Soil Resistivity - Probe Depth
The measured resistivity is the average at a depth equal to the horizontal spacing of the probes. The depth at which the resistivity is measured is not dependent on the probe depth.
The lead lengths are not part of the measurement and the resistance does not have to be deducted from the measurement.
Resistivity is measured in ohm-meters, not ohms.
RE: Soil Resistivity - Probe Depth
p = 2 * pi * a * R. (where a is the probe spacing and R is the measured resistance).
Some software (such as CDEGS) will account for the probe depth when calculating resistivity. To perform the calculations yourself, refer to equation 44 in IEEE 80.
I hope this helps.