Dielectric Constant Measurement of Railroad Ballast and Application of STFT for GPR Data Analysis
نویسندگان
چکیده
Abstract Ballast fouling in railroad substructure is detrimental to railroad track effectiveness and its structural capacity. Ground penetrating radar (GPR) provides a rapid, effective and continuous approach to assess railroad substructure condition. However, unknown ballast dielectric constant and unclear interface between clean and fouled ballast limit the GPR assessment accuracy. In this study, controlled laboratory testing was conducted to accurately determine the dielectric constants of two types of ballast: granite and limestone, based on the GPR data collected on ballast under various fouling and moisture conditions. In addition, short-time Fourier transform (STFT) spectra were built for ballast under various conditions using the collected GPR data. The study showed that STFT method was effective in locating fouling and trapped water in tested ballast. Furthermore, using laboratory-predicted ballast dielectric constants in GPR data analysis improved the accuracy of ballast condition assessment.
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