American Society of Civil Engineers


Ground Penetrating Radar Technology to Locate Plastic Pipes and Lava Tubes


by Leonhard E. Bernold, M.ASCE, (Associate Professor, Dept. of Civil Engineering, NC State University, Raleigh, NC 27695) and Mark Immer, (Visiting Research Assistant, Construction Automation & Research Laboratory, NC State University, Raleigh, NC 27695)

pp. 24-31, (doi:  http://dx.doi.org/10.1061/40722(153)4)

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Document type: Conference Proceeding Paper
Part of: Engineering, Construction, and Operations in Challenging Environments: Earth and Space 2004
Abstract: The demand for new buried utilities is growing with new construction, reconstruction, and the growth of the subsurface infrastructure worldwide. As a result, contractors are busy digging and trenching into the ground in order to bury new pipes. Because the machinery for placing the new utilities underground, such as backhoe excavators, trenchers, augers, drills, and plows, don’t "feel" when they are getting close to already buried object, utilities are easily damaged. Despite great efforts in locating existing utilities before a contractor is allowed to dig, accidents occur in great numbers. A key problem of the presently available hand-held technologies to detect underground utilities before digging is the inability to reliably predict the exact location (e.g., depth) of existing utilities. One particularly difficult problem represent plastic pipes that are being used to deliver gas in neighborhood networks. Currently no reliable technology exists that will provide accurate information about the location of buried gas pipes. One promising exception is ground penetrating radar (GPR) that has received a lot of attention by researchers to find mines made mostly of plastic. Its electromagnetic pulses are being reflected by changing density and works best when the target object is very dense compared to the surrounding (e.g., steel bar in soil.) However, plastic pipes filled with gas are dielectrically less dense thus offering a special challenge for GPR. In 1993, the Construction Automation and Robotics Laboratory (CARL) at NC State University started an initiative to address the problem of utility damages during construction. The core idea was to provide an equipment operator with his own sensing system that alerts him of a danger rather then to depend on the hand-held approach used by Underground locators today.


ASCE Subject Headings:
Buried pipes
Plastic pipes
Probe instruments
Radar
Tubes