USING TIME-DOMAIN REFLECTOMETRY FOR REAL-TIME MONITORING OF SUBSIDENCE OVER AN INACTIVE MINE IN VIRGINIA
Closure activities at the United States Gypsum Company facility in Plasterco, Virginia, include realignment of an existing highway outside the predicted limits of long-term subsidence. Concerns about the possibility of subsidence along the existing highway being induced by construction activities, or in the former plant area where excavated rock was being placed, motivated the installation of a real-time monitoring system based on time-domain reflectometry (TDR). This technology involves interrogating solid metallic coaxial cables to determine locations and magnitudes of cable deformation. When the cables are grouted into drill holes and trenches, TDR can be used to determine the location and rate of precursor subsurface movement that is causing cable deformation. Manual monitoring of three cables began in June 2001. Then, during 2002, system capabilities were expanded to automated real-time monitoring of 21 cables with lengths that varied from 10 m (30 ft) to 270 m (886 ft) for a total greater than 2,500 m (greater than 8,200 ft) of cable. The cables were installed in angled holes beneath the existing highway, in trenches along the highway, and in trenches over the former plant area where rock excavated for the new alignment was being placed. The automated monitoring system was controlled by a programmable data logger and incorporated a callback capability. Whenever the difference between the baseline measurement and the current measurement at any location along a cable exceeded a preset alarm threshold, the data logger would initiate a call to responsible personnel.
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Availability:
- Find a library where document is available. Order URL: http://www.trb.org/Main/Public/Blurbs/155397.aspx
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Supplemental Notes:
- This paper appears in Transportation Research Record No. 1874, Geology and Properties of Earth Materials 2004.
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Corporate Authors:
500 Fifth Street, NW
Washington, DC United States 20001 -
Authors:
- O'Connor, K M
- Crawford, J
- Price, K
- Sharpe, R
- Publication Date: 2004
Language
- English
Media Info
- Features: Figures; Photos; References; Tables;
- Pagination: p. 147-154
- Monograph Title: GEOLOGY AND PROPERTIES OF EARTH MATERIALS 2004
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Serial:
- Transportation Research Record
- Issue Number: 1874
- Publisher: Transportation Research Board
- ISSN: 0361-1981
Subject/Index Terms
- TRT Terms: Alarm systems; Automation; Coaxial cables; Data logging; Deformation; Mines; Monitoring; Real time data processing; Road construction; Safety; Subsidence (Geology); Time domain reflectometers
- Geographic Terms: Virginia
- Subject Areas: Geotechnology; Highways; Safety and Human Factors; I42: Soil Mechanics;
Filing Info
- Accession Number: 00983232
- Record Type: Publication
- ISBN: 0309094690
- Files: TRIS, TRB
- Created Date: Dec 7 2004 12:00AM