Ground Penetrating Radar Evaluation and Implementation

Six commercial ground penetrating radar (GPR) systems were evaluated to determine the state-of-the-art of GPR technologies for railroad track substructure inspection. Phase 1 evaluated GPR ballast inspection techniques by performing testing at the Transportation Technology Center (TTC) in Pueblo, CO. The evaluation was conducted at the Facility for Accelerated Service Testing (FAST) on the High Tonnage Loop (HTL). Investigators from TTC compared the ballast fouling and layer depth outputs of different GPR systems. The outputs of the different systems were compared with one another and with other known conditions. Also, a moisture sensitivity test was performed to confirm the ability of GPR to sense relative changes in moisture. Three different proprietary methods were used to determine ballast fouling. Scattering (System 1) and dielectric dispersion methods (Systems 2–5) produced generally similar results, whereas the propagation analysis method (System 6) produced significantly different results. A number of ballast samples were also taken from trenches at various locations on the HTL at FAST, and sieve analysis was performed to define the particle size distribution of the sample. Less emphasis was eventually placed on this approach, because there were limitations to comparing discrete ballast samples with the GPR data (in terms of where the samples were taken) and relating them to the limited amount of ground truth data available.


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Media Info

  • Media Type: Digital/other
  • Features: Figures; Photos; Tables;
  • Pagination: 4p
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    Open Access (libre)

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Filing Info

  • Accession Number: 01535324
  • Record Type: Publication
  • Files: TRIS, USDOT
  • Created Date: Aug 27 2014 10:47AM