As the number and length of high-speed railway tunnels increase in China, implicit defects such as insufficient lining thicknesses, voids, and poor compaction have become increasingly common, posing a serious threat to train operation safety. It is, therefore, imperative to conduct a comprehensive census of the defects within the tunnel linings. In response to this problem, this study proposes a high-speed railway tunnel detection method based on vehicle-mounted air-coupled GPR. Building on a forward simulation of air-coupled GPR, the study proposes the F-K filtering and BP migration algorithms based on the practical considerations of random noise and imaging interference from the inherent equipment. Through multi-dimensional quantitative comparisons, these algorithms are shown to improve the spectrum entropy values and instantaneous amplitude ratios by 4.6% and 11.6%; and 120% and 180%, respectively, over the mean and bandpass filtering algorithms, demonstrating their ability to suppress clutter and enhance the internal signal prominence of the lining. The experimental results are consistent with the forward simulation trends, and the verification using the ground-coupled GPR detection confirms that air-coupled GPR can meet the requirements of high-speed railway tunnel lining inspections. A comprehensive GPR detection model is proposed to lay the foundation for a subsequent defect census of high-speed railway tunnels.
With the increasing number and aging of railway tunnels, regular inspection will be an important means to ensure the safety for operation railways. A train-mounted ground penetrating radar system with cores of air-coupled antennas and shared time-window model has been developed to allow for long-distance and fast inspection of tunnels. The system consists of 6 groups of air-coupled antennas with center frequency of 300 MHz. The distance between antenna and lining is 0.5–4.0 m, the scanning rate of the system is 976 scans/Sec and the detection depth of the GPR can reach to 2.5 m. Under the theoretical design, the maximum speed of train can reach 70.27 km/h with a scan interval of 0.02 m. The test results on Shenyang-Dandong railway passenger dedicated line show that the system can identify the thickness of lining, the void and the backfill state behind lining.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.