Applications of Electromagnetic Waves for Void and Anomaly Detections

摘要

Knowledge of the existing roadway condition is vital to transportation government agencies for management and safety purposes. Verifying the presence and extent of subsurface defects/voids is vital to prevent failures and accidents from occurring. A nondestructive and noninvasive geophysical method, ground penetrating radar (GPR), which utilizes electromagnetic waves, was employed in this study. Four field projects are presented in this study to demonstrate the application of electromagnetic waves for detection of voids and anomalies. Auguring and excavation were used to verify the suspicious areas that were located by the electromagnetic waves. Voids and different subsurface features, like rebar, geo-grid, and geo-textile, were successfully detected. A large negative peak that appears in the wave form is an indication of a dry void. Void sizes, ranging from a few centimeters to several meters, were successfully detected. Early identification of concealed subsurface voids under the roadway structure can prevent major failures from occurring. The methodologies presented in this study are applicable to many other projects.