GPR signal attenuation through fragmented rock

Abstract

This paper presents results on detecting large rock fragments in rock piles using ground penetrating radar (GPR). The authors are researching sensors to augment the image provided to the remote operator, assisting with detection of oversized fragments beneath the surface. The attenuation of the GPR signal was calculated over the band 0-3 GHz from the signal energy in the frequency domain. The results show that attenuation measurement allowed the samples which included a large fragment to be differentiated from samples only containing smaller rock fragments. By combining velocity analysis with attenuation the rock samples can be further differentiated from samples containing air pockets or irregular surfaces. The combination of attenuation and signal velocity allowed prediction rates to detect the presence of large rock fragments over 93% correctly in laboratory testing.

GPR Clutter Amplitude Processing to Detect Shallow Geological Targets

“…For that reason, the resultant images are noisy and may lead to misinterpretation. This clutter is commonly observed in the analysis of shallow quaternary geology [19], in the assessment of civil structures where pathologies disintegrate specific zones of the media [20] and in fragmented rocks [21]. Therefore, this clutter might be related to physical characteristics of the media, such as size grain distribution, fissures, small voids and other heterogeneities.…”