Ground resistivity testing should it be done after site grading?

[Gotpowerflow]

Hello,

I was having a conversation with a college regrading soil resistivity testing readings. We were arguing weather or not it makes sense to get soil readings before site grading. To me it makes more sense to get the readings after site grading. In this way, I think, I will get more accurate readings to use in the soil modeling software and what if the soil used for the grading is not the same as the native soil. Is there a benefit to get soil resistivity readings prior and post site grading? I just do not see the benefit.

Thanks

 

[cuky2000]

If you can Weight to do the grounding design at a later time, it is more accurate to test the soil after the grading is completed.

Most soil resistivity test that I was involved in is performed in native soil ahead of time to perform the engineering calculation and design to complete the below-grade design package.

Engineering judgment is recommended to adjust the test to account for the soil grading and any weather conditions during the time the soil resistivity test is performed.

 

[dauwerda]

In my past experience working for a large utility we would have the soil resistivity testing done both prior and post grading. The prior testing would be done at same time the geotechincal engineering firm was doing borings for foundation design recommendations. This is what would be used for preliminary design of the grounding grid. The testing would then be performed post site work to verify the prelim design was adequate or would be updated if necessary.

 

[Bill West]

Twice the properties staff discreetly bought a site, a station design was made and construction started ...only to find that the soil was unexpectedly poor. After that when properties located a site some discrete method was worked out to check the soil before committing to the location. Both projects required running a ground feeder a distance outside of the station to find suitable soil.

Bill