Perturbation mapping of water leak in buried water pipes via laboratory validation experiments with high-frequency ground penetrating radar (GPR)

• Published in: Tunnelling and underground space technology 2016-02, Vol.52, p.157-167
• Main Authors: Lai, Wallace W.L., Chang, Ray K.W., Sham, Janet F.C., Pang, K.
• Format: Article
• Language: English
• Subjects: Buried pipes; Ground penetrating radar; Leaks; Perturbation; Pipe; Polyvinyl chlorides; Sand; Water leak; Water perturbation patterns; Water pipelines
• ISSN: 0886-7798; 1878-4364
• DOI: 10.1016/j.tust.2015.10.017

[Display omitted] •We map GPR perturbation patterns of leak point and wetting front.•We analyzed four stages of wetting patterns explained by GPR results.•Patterns are explained by well-established GPR theories. This paper studies the perturbation patterns of GPR images as a tool for water leakage detection in buried water pipes with laboratory experiments. Different perturbations patterns on GPR signals due to a water leak of metallic and PVC pipes buried in a sand box, were mapped and studied with controlled water injection and leak volume, as well as a fixed leak position in the pipes. These perturbation patterns of signal strength include the tale-tell signs of a central leak point and propagation of the radial wetting front vortex centered around the leak point at different injection times. These patterns, compared to the no-leak dry condition, were interpreted with the conventional principles of dielectric contrast and reflection coefficients, and the associated reflection and absorption mechanisms. It is believed that this set of data will serve as an image matching fingerprint to identify and map water leaks in the field.