Enhancing condictivity of soil?

[Patgeotech]

I thought I would post this qestion in the electrical forum rather than geotechnical and I would appreciate your electrical perpspectives and comments.

We are working in a dry area exposed to high seasonal fluctuations resulting in high resitivity values (unacceptable) during summer months. The site soil conditions comprise of dry to slightly moist with depth fine sand (variable silt content), which is underlain (at depths of 1.5 to 2.0 metres) by moist clayey silty sand (fairly low resistivity, which is lower than target value of 500 ohms per metre, so regarded as good).

We are constructing a platform which involves the construction of an earth mat in the platform. We require a resistivity of 500 ohms per metre or less and the fine sand does not meet this target during summer months. We therefore need to add an earth enhancing compound to the sand (to make platform more conductive) and being a non-electrical engineer, I am unsure as to what options are available to us. I would be interested to hear what others have added to sandy soils to lower the resistivity. I am thinking about using lime mixed in with the sand to lower the restivity around the copper strips, but again am a bit unsure about whether this would be good enough.

 

[waross]

Look here for Erico Ground Enhancement Material (GEM)

http://www.erico.com/globalSearch.asp?keywords=gem

http://www.erico.com/products/GEM.asp

http://www.erico.com/static.asp?id=27

http://www.erico.com/static.asp?id=43

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[djs]

Ground rods driven into the clay? Here in Florida we have the same issue. Additives are generally a no-no because they will wash away with the rains. So we drive some really deep ground rods.

 

[zeusfaber]

Don't suppose the old trick of piping all your aircon condensate lines to empty over your earth point is going to be much help once you get to this scale.

A.

 

[magoo2]

We've put some ground rods in concrete. The concrete improves the contact area of the rod and holds in mositure.

 

[VEBill]

Some of the lightning protection websites have good info on earth grounding. I've read about the concrete trick before.

 

[DRWeig]

That's what I was going to suggest, magoo2. Google up "ufer ground," it's saved my skin in bad soil before. There's no reason you have to keep it to the suggested dimensions, either. Deeper would help too.

Best to you,

Goober Dave

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