1. LATEST USE OF GROUND PENETRATING RADAR FOR RAILWAY APPLICATIONS
Damien Foun,
Geotechnical Engineer,
Civil Engineering Services, QR

2. LATEST USE OF GROUND PENETRATING RADAR FOR RAILWAY APPLICATIONS
Introduction
Recent QR developments with GPR testing (since early 2004),
Development of GPR by QR during 2006,
Latest GPR developments outside QR

3. INTRODUCTION Ground penetrating radar (GPR) - description
QR currently uses Groundprobe Pty. Ltd. and GBG Australia Pty. Ltd. for GPR testing services.
GPR testing can provide valuable information for
Track upgrade projects,
Assessment of track sections for track maintenance,
Specialist projects.

4. INTRODUCTION

5. DEVELOPMENTS SINCE 2004
Improvements in determining positions of GPR testing information with GPS:
Previously a measuring wheel was used,
GPS referenced to track kilometrage, though GPS co-ordinates of track kilometrages required.
Data positioning accuracy further improved by using video cameras.

6. DEVELOPMENTS SINCE 2004
For GPR testing for measurement of ballast depth, GPS co-ordinates added to video image and GPR traces.

7. DEVELOPMENTS SINCE 2004
Presentation of ballast depth information (base of ballast layer) using 3-D surfaces.
3-D surfaces clearly indicate the locations of ballast depth features.

8. DEVELOPMENTS SINCE 2004

9. QR RESEARCH DURING 2006
During 2006, QR have been investigating the use of GPR equipment for the following applications:
APPLICATION
CURRENT METHOD
BENEFIT OF USING GPR
Measurement of ballast fouling levels
Ballast sampling, then laboratory testing
Continuous testing
Laboratory testing not required.
Locating buried objects within ballast -
Prevent damage to ballast cleaning equipment.

10. QR RESEARCH DURING 2006
APPLICATION
CURRENT METHOD
BENEFIT OF USING GPR
Locating cracks in timber sleepers
Visual inspection
Test at possibly higher speeds
Locating cracks in formations
Trenching
Continuous testing along track sections
Measuring ballast depths with GPR at high speeds (up to 60 km/h) also investigated.

11. QR RESEARCH DURING 2006 Methodologies of main two objectives.
Measurement of ballast fouling levels
Test a track section with GPR equipment,
Obtain ballast samples and perform PVC testing (at approximately the same time as step 1),
Correlate GPR signals with PVC test results to develop an equivalent PVC result for particular GPR signals.

12. QR RESEARCH DURING 2006 Locating objects in ballast
Bury several objects under a track section,
Perform GPR testing.

13. QR RESEARCH DURING 2006
3-D radar planned for field trials. 3-D radar attached to frame for high speed testing (not in contact with rails).

14. QR RESEARCH DURING 2006 3-D radar not successful.
Therefore, alternative GPR equipment trialled for measurement of ballast fouling levels.

15. QR RESEARCH DURING 2006

16. QR RESEARCH DURING 2006
Radar signal interference from steel and timber sleepers significant,
Further trial with GPR horn antenna rotated 900 may be performed,
3-D radar may be trialled again at a later date after technology has been proven.

17. OVERSEAS GPR DEVELOPMENTS
Presenting GPR data, video and maps in a single display,
Testing speed of up to approximately 160 km/h possible.

18. SUMMARY Recent developments
Improvements in positioning method and accuracy,
Use of 3-D charts.
Desirable applications
Measurement of ballast fouling levels,
Locating objects buried in ballast,
Locating cracks in timber sleepers and track formations.

19. SUMMARY GPR testing at 60 km/h also desirable. Overseas developments
Presenting GPR data, video and maps in a single display,
Testing speed of up to approximately 160 km/h possible.

20. LATEST USE OF GROUND PENETRATING RADAR FOR RAILWAY APPLICATIONS
Questions ?