Soil piping: networks characterization using ground-penetrating radar

Soil piping remains a relatively unexplored phenomenon despite its substantial impacts on watershed-scale water and sediments transfer in numerous locations around the world. One of the main limits regarding the study of this singular process is characterization of the pipe networks (defining number, position, dimension and connectivity of pipes). In this context, non-invasive subsurface imaging using ground-penetrating radar (GPR) seems a promising technique. An exploratory methodology was developed to assess the ability of GPR to characterize pipe networks in Loess-derived soil. This methodology relies on (1) high spatial resolution scanning and (2) detection of electromagnetic sub-surface indicators of soil pipe (reflection hyperbolas and strongest reflections). For a 50 m x 50 m scanned zone, results show that combining these indicators can provide interesting clues about a potential pipe network. Three probably interconnected pipes were revealed. However, results show that the proposed methodology needs specific improvements in signal processing, object detection and system configuration in order to enhance and facilitate subsurface networks characterization.