Investigation of Bored Piles Under Deep and Extensive Plinth Foundations: Method of Prospecting and Mapping with Pulse Georadar

Ground Penetrating Radar surveys on structures have a wide range of application and they are very useful in solving engineering problems: from detecting reinforcement, studying concrete characteristics, unfilled joints, analyzing brick elements, detecting water content in building bodies, and evaluating structural deformation. They generally pursued small investigation areas with measurements made in direct contact with target structures and for small depths. In this paper we are illustrating an exploration on plinth foundations, supported by drilled piles, submerged in soil, extensive, deep and uninformed. Pulse GPR prospecting was performed in common-offset and single-fold, bistatic configuration, exploiting the exposed faces of an excavation around the foundation. In addition, 3 velocity tests were conducted including 2 in common mid-point and one in zero-offset transillumination in order to explore the range of variation of relative dielectric permittivity in the investigated media. The electromagnetic back-scattering analysis approach allowed us to extract the weighted average frequency attribute section. In it, anomalies emerge on the presence of drilled piles with 4 15 piles with an estimated diameter of 80 cm.