Study On Vehicle-mounted GPR Detection Technology For Highway Tunnel

In recent years,China’s highways have developed rapidly,and highways are the "main artery" of traffic.As an important structure for the safe of road traffic,road tunnels will have defects due to geological disasters,construction defects,poor maintenance and other reasons.These defects are hidden dangers for safe and need to be eliminated through regular inspections.The main method for detecting internal defects of road tunnel lining is ground penetrating radar technology.At present,conventional GPR technology mainly adopts ground-coupled radar.which is difficult to realize rapid survey of the tunnel lining due to low efficiency and slow speed.The Vehicle-mounted GPR has the characteristics of non-contact,far-distance,fast scanning,so it has a good application prospect in road tunnel inspection.The thesis researches on the detection technology of road tunnel vehicle-mounted GPR through theoretical research,numerical simulation,online testing and engineering application,and explore its application direction.The main research contents are as follows:(1)Based on the theory of GPR,the thesis analyzes propagation characteristics of the air-coupled GPR,and studies the technical parameters and detection capabilities of air-coupled antennas.Research work verifies that it is feasible to use air-coupled radar antenna to detect road tunnel lining under non-contact conditions.(2)The thesis analyzes the current situation and existing problems of road tunnel lining detection technology,and studies the road tunnel lining structure parameters and the working conditions of vehicle-mounted GPR detection.The thesis proposes a technical scheme for road tunnel inspection by using the vehicle-mounted GPR.The detection equipment is installed on the detection vehicle,the distance between the antenna and the tunnel lining surface is 0.5～2.0 m,and the detection speed is 10～60 km/h.(3)The thesis designs a servo system for vehicle-mounted GPR,the servo system uses a manipulator to fix radar antenna.The detection distance is controlled by manipulator.The servo system can be equipped with multiple radar antennas,the vehicle-mounted GPR system can simultaneously detect 4 tunnel survey lines.(4)The research results were applied to a highway tunnel inspection project,the detection work adopts the vehicle-mounted GPR technology scheme,and completed the inspection of the quality of 19 tunnels.The length of the tunnel is 60 km.The test results show that the vehicle-mounted GPR technology can be applied to detect the lining thickness,void of lining,rebar,steel arch,surrounding rock disturbances.