Scattering Analysis of Railroad Ballast Using Ground Penetrating Radar
Railroad ballast plays an important role in supporting heavy rail loading, preventing the deformation of track and providing drainage of water from the track structure. However, ballast fouled by the breakdown of ballast aggregate and/or the infiltration of fines, which undermine ballast functions, may result in damage to the rail system, such as track settlement. Compared to uniformly graded, clean ballast, fouled ballast has a finer, well-graded particle size with fewer air voids. Early detection of fouled ballast can optimize the life-cycle cost of the ballast system. Ground penetrating radar (GPR), a nondestructive method, can be used to rapidly, effectively, and continually assess the conditions of railroad track substructure. Ballast under different conditions generates various GPR electromagnetic scattering patterns. A field GPR survey was conducted in summer 2005 to assess the integrity of the ballast of railroad test tracks at the Transportation Technology Center, Inc. (TTCI) in Pueblo, Colorado. Three continuous parallel longitudinal images along the tested tracks were obtained using multiple sets of 1GHz and 2GHz air-horn antennae mounted on a hi-rail vehicle. The 2GHz antenna was found to be more sensitive to the change in scattering pattern. Appropriate data processing was used to remove the effects of the rails to obtain clear GPR images of the subsurface layers. From the image analysis, in addition to ballast thickness, the ballast condition can be assessed, including variations in layer thicknesses along the track, pockets of water trapped in the ballast, and ballast fouling.
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Corporate Authors:
500 Fifth Street, NW
Washington, DC United States 20001 -
Authors:
- Al-Qadi, Imad L
- Xie, Wei
- Roberts, Roger
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Conference:
- Transportation Research Board 86th Annual Meeting
- Location: Washington DC, United States
- Date: 2007-1-21 to 2007-1-25
- Date: 2007
Language
- English
Media Info
- Media Type: CD-ROM
- Features: Figures; Photos; References; Tables;
- Pagination: 15p
- Monograph Title: TRB 86th Annual Meeting Compendium of Papers CD-ROM
Subject/Index Terms
- TRT Terms: Air voids; Drainage; Ground penetrating radar; Railroad facilities; Railroad facility operations; Railroad rails; Railroad tracks; Railroad transportation; Railroad vehicle operations; Railroads; Track ballast
- Subject Areas: Hydraulics and Hydrology; Railroads;
Filing Info
- Accession Number: 01045960
- Record Type: Publication
- Report/Paper Numbers: 07-2273
- Files: TRIS, TRB
- Created Date: Apr 10 2007 9:22AM