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.
06:17 Mar-09-1998 Rolf Diederichs Director, Editor, Publisher, Internet, PHP MySQL NDT.net, Germany, Joined Nov 1998 602
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.
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 : firstname.lastname@example.org
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 email@example.com for details (english language spoken)