Detection and Delineating of Hydrocarbon Contaminants by Using Time and Frequency Analysis of Ground Penetrating Radar

Abstract

This paper provides the results of using ground penetrating radar (GPR) me-thod to detect hydrocarbon products (diesel and gasoline) in a controlled lab test. The work addresses the environmental problem generated by the uncon-trolled leakage of hydrocarbon products and the subsequent contamination of plumes in the subsoil. Most of the research proposes the geophysical tech-niques to evaluate the plumes but some controversial were discussed on how it affected the electrical and dielectric response depending on the excitation of the non-invasive method. The present work focuses on a comparative analy-sis of some signal attributes of the GPR traces to determine under what pre-mises the detection is properly done. These signal attributes were from the time and frequency domain as attenuation coefficient, instantaneous ampli-tude and frequency have been considered to analyze three different soil sam-ples. The laboratory tests consist of buried liquid (total hydrocarbon of pe-troleum, so called TPH) bags in the soil sample boxes reveal the range of tar-get detection and consistency of data on the controlled test regarding the di-electric soil characterization and the delimiting position and depth. Instanta-neous amplitude and time-frequency shift are revealed as promising signal attributes to accurate detection of the TPH presence. Numerical simulation data were also carried out to interpret the signal reflections on radargrams and to confirm experimental trends and the benefits of using the above signal attributes in time-frequency domain.