The use of GPR technologies for utility mapping in underground distribution grid conversion - Brazil use case

Abstract

The ground-penetrating radar (GPR) has become a very important tool for nondestructive underground exploration. The GPR is capable of capturing reflections that form high-resolution lines of the shallow subsurface and underground utility. These lines are processed by an expert who draws a 3D model of what was captured. For objects at different depths, different sizes and materials to be found by technology, the equipment must have a wide frequency range. Low frequency waves make it possible to identify larger objects at greater depths and high frequency waves detect smaller objects at low depths. This case study shows a practical example of the usage of the GPR in the underground distribution grid in the city of São Paulo, Brazil. It was carried out within the scope of a R&D project called “Urban Futurability”, by Enel Dlstribulção São Paulo. The results of the scanning done over 9 km make it possible to use the 3D model combined with a high-precision GPS for the elaboration of an underground network project that draws the best path for the installations, identifying rocks, denser and less dense soils, groundwater and other interference, allowing the work to be executed in a more efficient way.