城市道路空洞的地面-管道雷达协同探测与联合成像

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

摘要:

城市道路空洞是造成道路塌陷事故的主要原因，调查发现空洞主要源于地下管线病害发生渗漏后形成。提出一种地面-管道雷达协同探测技术，建立地下目标探测足尺试验平台，对管线周边不同尺寸的空洞、含水空洞进行探测。结合考虑天线方向图校正的背向投影算法，对管道附近空洞进行协同探测与数据联合成像，室外模型试验验证了该算法的可行性。结果表明：相较于现有地面雷达，管道雷达对地下管线周边的空洞探测结果有着更高的分辨率。同时，相较于传统的背向投影方法，本文提出的地面-管道联合成像方法可在抑制成像目标边缘反射伪影的同时对空洞顶部、底部以及混凝土管内部钢筋进行高精度成像。研究结果可为地下空洞的雷达数据解译提供参考。

关键词:探地雷达;管道雷达;空洞;背向投影;偏移

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.

Key words:ground penetrating radar(GPR);pipe penetrating radar(PPR);cavity;back-propagation;migration