Data analysis techniques for GPR used for assessing railroad ballast in high radio-frequency environment

Imad L. Al-Qadi, Wei Xie, Roger Roberts, Zhen Leng

Research output: Journal article publicationJournal articleAcademic researchpeer-review

46 Citations (Scopus)


Railroad ballast supports heavy rail loading, prevents track deformation, and provides drainage of water from the track structure. However, over time, ballast is fouled by the breakdown of ballast aggregate and/or the infiltration of fines, which undermine the ballast functions and affect the railroad track structural capacity. Ground penetrating radar (GPR) provides a rapid, effective, and continuous way to assess railroad track substructure condition; especially ballast. However, the GPR system faces some challenges during field surveys including high radio-frequency interference from railroad communication and automation, and strong reflections from rails. In this study, appropriate techniques were used to remove the interference and reduce the strong clutter from rails to obtain clear GPR data of railroad substructure. A time-frequency method, short-time Fourier transform, was then applied to extract ballast fouling condition over depth. A field survey using multiple sets of 2-GHz air-horn antennae was conducted during summer 2007 at the Transportation Technology Center, Inc. in Pueblo, Colo. Compared to ground-truth excavation and ballast gradation analysis results, GPR was found to be an effective technique to assess railroad track ballast substructure condition.
Original languageEnglish
Article number001004QTE
Pages (from-to)392-399
Number of pages8
JournalJournal of Transportation Engineering
Issue number4
Publication statusPublished - 1 Apr 2010
Externally publishedYes


  • Fouling condition
  • Ground penetrating radar
  • Radio-frequency interference
  • Railroad ballast
  • Time-frequency method
  • Ultrawide band (UWB)

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Transportation


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