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Proceedings Paper

Laboratory simulation of high-frequency GPR responses of damaged tunnel liners
Author(s): A. F. Siggins; Robert J. Whiteley
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Paper Abstract

Concrete lined tunnels and pipelines commonly suffer from damage due to subsidence or poor drainage in the surrounding soils, corrosion of reinforcement if present, and acid vapor leaching of the lining. There is a need to conduct tunnel condition monitoring using non-destructive testing methods (NDT) on a regular basis in many buried installations, for example sewers and storm water drains. A wide variety of NDT methods have been employed in the past to monitor these linings including closed circuit TV (CCTV) inspection, magnetic and various electromagnetic and seismic methods. Ground penetrating radar, GPR, is a promising technique for this application, however there are few systems currently available that can provide the high resolution imaging needed to test the lining. A recently developed Australian GPR system operating at 1400 MHz offers the potential to overcome many of these limitations while maintaining adequate resolution to the rear of the linings which are typically less than 0.5 meters thick. The new high frequency GPR has a nominal resolution of 0.03 m at the center of the pulse band-width. This is a significant improvement over existing radars with the possible exception of some horn based systems. This paper describes the results of a laboratory study on a model tunnel lining using the new 1.4 GHz radar. The model simulated a concrete lining with various degrees of damage including, heavily leached sections, voids and corroded reinforcing. The test results established that the new GPR was capable of imaging subtle variations in the concrete structure and that simulated damage could be detected throughout the liner depth. Furthermore, resolution was found to exceed 0.02 m which was significantly better than expected.

Paper Details

Date Published: 27 April 2000
PDF: 7 pages
Proc. SPIE 4084, Eighth International Conference on Ground Penetrating Radar, (27 April 2000); doi: 10.1117/12.383519
Show Author Affiliations
A. F. Siggins, CSIRO Division of Petroleum (Australia)
Robert J. Whiteley, Coffey Geosciences Pty. Ltd. (Australia)


Published in SPIE Proceedings Vol. 4084:
Eighth International Conference on Ground Penetrating Radar
David A. Noon; Glen F. Stickley; Dennis Longstaff, Editor(s)

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