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Ruperto-Carola University of Heidelberg (2008)

Ground penetrating radar as a quantitative tool with applications in soil hydrology

Gerhards, Holger

Titre : Ground penetrating radar as a quantitative tool with applications in soil hydrology

Auteur : Gerhards, Holger

Université de soutenance : Ruperto-Carola University of Heidelberg

Grade : Doctor of Natural Sciences 2008

Résumé
This work concentrates on the investigation of ground penetrating radar (GPR) with respect to applications in soil hydrology. The motivation is to expand the boundaries of processability and evaluability of GPR measurements. Therefore, a detailed review of the fundamentals for electromagnetic wave propagation is given. First, theoretical and experimental descriptions of the dielectric material models are introduced. This is followed by an overview of different modeling approaches in electrodynamics which differ in their physical complexity. The ray approach, a plane wave description and a Green’s function approach are presented, where the last simulates a vertical dipole in a horizontally layered medium. With the help of these modeling approaches, some specific electromagnetic wave phenomena are studied. For instance the reflection and the refraction at continuously varying dielectric properties are analyzed, which can stem for example from the water distribution in soils. Furthermore, the ground wave is studied regarding its evanescent wave behavior. This can be observed, when the wave couples into the air. As an outcome of the theoretical considerations, two novel measurement techniques and their evaluation approaches are presented. One technique is the lift measurement, which enables the detection of evanescent waves. The other technique is the multi-channel method, which allows a simultaneous access to reflector depth and average water content up to several hundred meters.

Mots Clés : Elektromagnetische Reflexionsmethode, Bodenphysik, Wassergehalt

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Page publiée le 11 mars 2009, mise à jour le 5 janvier 2019