Research On Road Tunnel Detection Technology Based On Vehicle-borne Non-contact Radar

With the development of Highway Engineering in China,the number and mileage of tunnel engineering are increasing.Correspondingly,the workload of tunnel maintenance and inspection increases rapidly,and the quality of lining structure determines the safety of long-term use of the tunnel.Therefore,the quality inspection of highway tunnel is particularly important.The traditional detection methods rely on manual work in the detection process.Some parts of the detection need to set up brackets.The detection process will affect the normal operation of the tunnel,and the quality of the detection can not be guaranteed.Ground penetrating radar(GPR)is an advanced method to detect structural quality in highway tunnel engineering.However,conventional radar detection methods mostly use hand-held radar antenna for wall-to-wall detection.There are also some problems such as low detection efficiency and high security risks.The efficiency,accuracy and security of these detection methods can not meet the actual needs.Therefore,the development of non-contact radar detection technology has become a necessary requirement.The research work of this paper is as follows:(1)This paper deeply studies the propagation law of electromagnetic waves of ground penetrating radar and its basic working principle;(2)Using the FDTD-based numerical simulation software GprMaxV2.0,combined with the Matlab code,the forward model of the target in different air distances and different conductivity media is established and the corresponding response characteristics and laws are obtained.(3)A forward model of lining thickness,back void,crack and void is established for the plain concrete lining and reinforced concrete lining of the tunnel,and the typical radar profile of these quality defects is obtained.(4)By pouring concrete model slab,using different types of radar and antenna for outdoor physical experiment detection,and processing the experimental data through post-processing method,the real and accurate non-contact test results can be obtained.(5)According to the characteristics of highway tunnels and lining conditions,three different schemes based on vehicle-borne non-contact radar scanning system are designed,which are: fixed wheelbarrow scanning system with support arm,four-channel fast scanning system and single-channel transverse movable scanning system.In this paper,the mathematical relationship between air distance and radar reflected signal intensity,the mathematical relationship between electrical conductivity and radar reflected signal intensity,the radar profiles of different concrete defects are obtained by simulation;the non-contact detection data of diseases are obtained by physical experiments;and three non-contact radar vehicle solutions are designed,which are of great importance to the rapid detection of highway tunnels.Meaning.