Evaluation of road settlements on soft ground from GPR investigations

Mobile GPR investigation was carried out to estimate the residual settlements of expressway constructed on soft gromds by measuring the thickness of pavement. Preliminary tests were conducted in the KHC Test Road not only to verify the application but also to obtain the proper driving speed. The thickness obtained by mobile GPR investigation was compared with that of coring, which showed acceptable results. The variations of surface elevation were also measured by level surveying. The settlement was evaluated through the summation of the thickness of overlaid pavement and the difference of surface elevation. For the evaluation of present settlement conditions, GPR can be used effectively without intercepting traflic of the road.