Characteristics Analysis of Ground Penetrating Radar Signals for Ground water Pipe Leakage Environment

Ground Penetrating Radar (GPR) has a good prospect in the detection of underground water pipeline leakage. Previous studies have shown that the underground water pipes leakage can form oscillating hyperbolic signals in GPR profile, but its formation mechanism is not clear. To reveal the formation mechanism of GPR signal characteristics after underground pipeline leakage of different materials, physical model test and multi-physics numerical simulation are carried out to analyzes the characteristics of GPR signals before and after leakage, the formation mechanism of oscillating hyperbolic signal of PVC/metal pipe after leakage and the propagation path of electromagnetic wave. The results show that a stratified leakage zone appears around the underground water pipe after leakage, and more interface reflections and multiple waves bouncing between interfaces occur during the propagation of electromagnetic waves. After the leakage of PVC pipe, creeping wave signals and the reflected signals at the top and bottom of the PVC pipe are reflected many times in the leakage zone to form complex oscillatory hyperbolic signals, while there are multiple reflections between the pipe outer wall and the leakage zone after the metal pipe leakage. The results are helpful to promote the practical applications of GPR to underground pipeline leakage detection and related data interpretation.