Evaluation of rutting depth in unpaved roads using electromagnetic wave techniques

This study evaluates the applicability of ground penetrating radar (GPR) and time domain reflectometry (TDR) for assessing rutting depth on unpaved roads. A testbed is constructed using sandy soil, and vehicular loading is applied through repeated passes of a dump truck (0, 100, 200, and 500 times). The rutting depth is estimated based on the travel time extracted from the GPR images and permittivity values obtained from the TDR measurements. The accuracy of these estimates is compared with the results of dynamic cone penetrometer (DCP) tests. Additionally, the rutting depth estimated by GPR analysis is compared with the values obtained using the conventional straightedge method. The results indicate that incorporating GPR with TDR enables accurate estimation of subsurface interface depths. Moreover, while conventional methods tend to underestimate the rutting depth owing to the deformation of the reference surface, the GPR-based analysis shows minimal error from such deformation. This study demonstrates that GPR and TDR can be powerful tools for evaluating the rutting depth across an entire road cross section.