Detection of subsurface utilities using GPR techniques

The nondestructive evaluation of buried utilities is of interest for engineering and environmental applications. The use of Ground Penetrating Radar (GPR) for buried utility detections is one of the most common geophysical techniques due to its capacity for accurate results in either horizontal or vertical directions. Electric cables and metallic pipes are easily recognized on GPR profiles due to their high dielectric values relative to surrounding soils. In this study, 12 different sites are investigated using GPR techniques to detect buried utilities, such as electrical cables, water, and derange pipes located within the first 3 meters of the ground's surface. At each investigation site, two perpendicular GPR profiles, using a 200 MHz antenna, are collected in order to detect any buried utilities. The area under study is excavated after GPR data acquisition for manual verification. It is found that electric cables are easy to recognize on radar profiles by their sharp hyperbola edges and multiples extending to the bottom of the data set. Water pipes have especial characteristics on GPR lines, indicated by a thick, small hyperbola without any multiples. The presence of cement blocks masks any object beneath them, but they are prominent on radar lines as high amplitude reflections.