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Technical Discussions
Simon Stewart
Simon Stewart
03:38 Mar-03-1998
Underground bare earth grid detection

I'm interested in how to detect bare cabling and its
condition beneath soil without complete prior knowledge.

An earth grid (40x40M say) is typically large
interconnected squares (4x4M say) of bare wire.
They are buried typically at a depth of 1M, with
a layer of about 150mm of crushed rock upon the
soil surface. Live busbars carrying current are
about 3.5M overhead. Access is only provided to very
limited points.

I've looked a bit into Ground Penetrating Radar, and
it seems it may have difficulties with the crushed rock
reflecting and also with detecting small discontinuities.
It would otherwise seem ideal for locating the grid.

I've looked at current injection into the grid and
detection of magnetic fields, but problems arise due
to alternate paths existing and the need for prior
signature magnetic field curves.

Can any successful techniques be thought of?

Thanks,
Simon Stewart


 
 Reply 
 
Rolf Diederichs
Director,
NDT.net, Germany, Joined Nov 1998, 617

Rolf Diederichs

Director,
NDT.net,
Germany,
Joined Nov 1998
617
06:17 Mar-09-1998
Re: Underground bare earth grid detection
I have information from the CORDIS Database availble that may be help you.
http://apollo.cordis.lu/cordis/GLOBALsearch.html

Abstract :
A Welsh company carries out research and consultancy for companies involved in waste management, land reclamation and
characterisation of the subsurface. The company uses the latest innovations in geophysical technology: ground radar; micro-gravimetry;
seismics and geo-electrical imaging. The rapid high resolution techniques can characterise large areas of land for a fraction of the time and
cost.

Subject Descriptors : Soil science; Technological hazards; Inspection, testing

Subject Index Codes : Earth Sciences; Safety; Measurement Methods

Market Applications : Environmental monitoring; Measurement systems; Instruments, measuring equipment

Stage of Development : Tested, available for demonstration

Collaboration Sought : Further research or development support

CONTACT:
Contact Name : RUSSILL, Nick
Contact Organisation : TerraDat UK Ltd
Address : PO Box 319
City : Cardiff
Region : South Glamorgan
Postcode : CF1 3UJ
Country : UNITED KINGDOM
Fax Number : +44-1222-874485
Electronic Mailbox : terradat@compuserve.com



 
 Reply 
 
Chris Worrall
Chris Worrall
07:36 Nov-03-1998
Re: Underground bare earth grid detection
I know of a Japanes company that markets a GRP detection device initially developed for just this sort of application. It became so successful that they now use it to detect land mines with 100% success rate. It is claimed to detect burried metal objects as small as 3 mm at a depth of 1 m. The company dealing with the product is called Voguenet and the device is called the Sencion alpha-pro. Contact Stephanie Swoll on sswoll@pa2.so-net.or.jp for details (english language spoken)


 
 Reply 
 

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