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Effect of a Discontinuity’s Aperture on the GPR Signal
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, Near Surface 2011 - 17th EAGE European Meeting of Environmental and Engineering Geophysics, Sep 2011, cp-253-00013
- ISBN: 978-90-73834-15-6
Abstract
The aim of this paper was to study effect of an opening to GPR signal, measured with 800 MHz and 1600 MHz transmitter/antenna. Tests were carried out in laboratory scale using two sawn rock blocks. The opening between them varied from 0 to 10 cm. First GPR signal’s velocity was defined in the blocks by calculating two way travel time, as the thickness of the blocks was known. Next the top and bottom of the opening were interpreted from the GPR profile by utilising theoretical change of the reflected signal’s phase in the opening. Openings apertures were calculated from the interpretations and compared to the real ones. Good results were achieved for the greatest apertures, but apertures smaller than 1/6 of the signals wavelength could not be interpreted due to signal summing. Summing could be less of a problem when using other filling materials than air in the opening. These are the next research subjects for the authors.