GROUND PENETRATING RADAR (GPR) TO INVESTIGATE SHALLOW CAVES IN KARST REGIONS

Shallow caves in karst regions pose significant hazards to engineering works, particularly to linear infrastructures such as highways, due to the risk of sudden ground collapse. Although conventional subsurface investigation methods, which are generally destructive, are widely used, they do not allow for the complete characterization of large areas, reinforcing the importance of nondestructive geophysical techniques such as Ground Penetrating Radar (GPR). Grounded in concepts of karst geomorphology and in the operation of the GPR method, this study evaluates the applicability of the technique for detecting shallow subsurface cavities. The main characteristics of karst environments and the fundamentals of GPR are presented. To support field investigations and data interpretation, a computational simulation of GPR responses was performed using the gprMax software, based on a real case identified during the construction of highway BR-414/GO, located in a limestone region in central Brazil. The results confirm the suitability of GPR as a nondestructive technique for detecting shallow cavities in limestone terrains and highlight the contribution of numerical modeling to radargram interpretation and to understanding the performance of the method in this type of environment.