Application Of Ground Penetrating Radar To The Inspection Of Quality Of Highway Tunnels

As tunnel is concealed work,its construction technology and construction environment are relatively complex,the control and evaluation of the construction quality are very important.When tunnel engineering is tested,the ground penetrating radar(GPR),with its characteristics of fast,nondestructive and continuous gradually replaces the traditional detection method,and is applied and developed widely.Based on the basic theory of electromagnetic field and the propagation rule of electromagnetic wave,the composition,working principle,detecting parameters and indexes of the ground penetrating radar(GPR)system are introduced in this paper.Using SIR-3000 ground penetrating radar(GPR)as an example,the methods of data acquisition,processing and interpretation are described in detail.Combined with the engineering testing example,the influence factors of ground penetrating radar(GPR)method and actual test results are illustrated.(1)The data acquisition method is systematically introduced when the quality of tunnel lining is tested,and the measuring line layout,parameter settings and medium parameters calibration are illustrated in detail;(2)The key points of radar data processing are interpreted,and the digital filtering,offset diffraction,deconvolution and hilbert transform which help to improve the radar image recognition are taken as graphic description;(3)The typical waveform radar images of common goal body in tunnel lining are summarized,and the identification method for the lining layer thickness,steel bar,steel arch,empty and uncompacted zone is explained;(4)Several factors influencing the detecting effect of ground penetrating radar(GPR)are analyzed,and they are summarized in detail from two aspects of instrument set parameters and testing environment,especially the factor of water content of media.Using ground penetrating radar(GPR)for nondestructive testing on the tunnel,according to the waveform characteristics of different target body,and combined with the design documents and construction materials,the tunnel lining structure can be analyzed,and the construction quality of tunnel lining is evaluated.At the same time,the typical radar images of the engineering test results in the paper can provide reference for other tunnel detection.