Ground-Pipeline Penetrating Radar Joint Detection Technology and Imaging Method for Urban Road Cavity Investigation

Abstract:

Cavities under urban roads have increasingly become a great threat to traffic safety. Most cavities are caused by the leakage of underground pipelines. Pipe penetrating radar（PPR） has been widely used in the cavity inspection near the underground pipeline. However， due to the attenuation of electromagnetic waves in the underground medium， it cannot accurately detect the upper surface of the cavity. This paper proposes a ground-pipeline penetrating radar joint detection technology to improve the accuracy of cavity inspection. An underground object detection platform is established to detect air and water-filled cavities with different sizes. In combination with the back-projection algorithm and antenna pattern correction， the cavity near the pipeline can be migrated by proposed joint imaging method. Laboratory experiment results show that the PPR has a higher resolution in cavity inspection compared with ground penetrating radar（GPR） detection. In addition， the undesired diffractive artifacts at the target edges can be suppressed while improving the migration accuracy with the proposed join imaging method. Both the top and bottom of the cavity as well as the reinforcement inside the concrete pipe can be reconstructed with high-resolution by the proposed joint imaging method. The result is helpful to promote the practical application of GPR and PPR to cavity inspection near the underground pipeline.