Affect of Frozen Soil on Resistivity Measurements
Affect of Frozen Soil on Resistivity Measurements
(OP)
Anyone have knowledge of how frozen dirt may affect measurements of soil resistivity? We need work done in northern Colorado to design the ground grid for a new substation and it appears that some of our recent cold weather has frozen the soils down to about 30".
Christopher Renedo, P.E.
ESC Engineering
Fort Collins, CO






RE: Affect of Frozen Soil on Resistivity Measurements
You could pull samples and do lab tests on the soils' top layers.
My field experience is that you can get resistivity numbers for the frozen soil and the layers underneath it using the 4-point Wenner method. But it is very difficult to get a good test connection to the soil. I had to salt the test probes, drill holes, drive deep stakes and used other tricks to get enough test current for the readings to stabilize. The results were suspect, but the wider spacing tests gave reasonable results for the deeper layers.