Hello Folks,

I'm looking at a geotechnical study done in 1990 for a buried pipeline where they measure soil conductivity of samples and it appears they inversed it to get resistivity. We perform resistivity testing along with other corrosion-related soil testing for pipeline and mse wall geotech studies regularly, but i am not familiar with this conductivity test. What i find most concerning is that some of the reported resistivities are 100X more resistive than i've seen with our field data with same units.

Out of 25 samples, here are the lowest and highest resistivities

Boring B-62, Depth 8.5-10, Soil Type CL, pH 7.3, Conductivity uMHO/cm 114.0, Resistivity 8,772 OHM-cm
Boring B-19, Depth 5-10, Soil Type MH, pH 5.4, Conductivity uMHO/cm 0.6, Resistivity 1,666,667 OHM-cm

the purpose of why i'm looking at this data is to find a few good spots to examine the buried ductile iron pipe for corrosion and pitting. i plan on doing some additional resistivity tests to confirm, but i was wondering if anybody has had a similar experience or has any insights to this. perhaps there is a limits of the test issue here that i don't know about.

thanks
-DSG