IDENTIFICATION OF PIPELINES FROM THE SECONDARY REFLECT WAVE TRAVEL TIME OF GROUND-PENETRATING RADAR WAVES

摘要

When using ground-penetrating radar to identify underground pipelines of similar dielectric constants (i.e. PE and PVC), misidentification is quite common. In this study, we apply reflected travel time of radar waves into the PE- and PVC- dielectric constants and the differentiation becomes possible. We have conducted the experiments using the non-metal PE- and PVC- pipelines as well as the heavy metal (iron) pipelines in a water environment. Based on a travel- time calculation, the dielectric constants of non-metal pipelines with similar composition (PE = 2.3 and PVC = 3.0) were quite close. The error between the experimental and theoretical values is acceptable in general engineering projects. It is also compliant with the standard error by the U.S. ASTMD4748-98 (the error range is about ± 0.2 inches or ± 0.508 cm). Therefore, the result of this study not only can be applied to detect the metal pipes, but also may be used to distinguish non-metallic pipes in a water environment.