Measurement of water pressure and deformation with time domain reflectometry cables

Charles H. Dowding*, Charles E. Pierce

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


Time domain reflectometry (TDR) techniques can be deployed to measure water pressures and relative dam abutment displacement with an array of coaxial cables either drilled and grouted or retrofitted through existing passages. Application of TDR to dam monitoring requires determination of appropriate cable types and methods to install these cables in existing dams or during new construction. This paper briefly discusses currently applied and developing TDR techniques and describes initial design considerations for TDR-based dam instrumentation. Water pressure at the base of or within the dam can be determined by measuring the water level within a hollow or air-filled coaxial cable. The ability to retrofit existing porous stone-tipped piezometers is an attractive attribute of the TDR system. Measurement of relative lateral movement can be accomplished by monitoring local shearing of a solid polyethylene-filled coaxial cable at the interface of the dam base and foundation materials or along adversely oriented joints. Uplift can be recorded by measuring cable extension as the dam displaces upward off its foundation. Since each monitoring technique requires measurements with different types of coaxial cables, a variety may be installed within the array. Multiplexing of these cables will allow monitoring from a single pulser, and measurements can be recorded on site or remotely via a modem at any time.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsSoheil Nazarian, Larry D. Olson
PublisherSociety of Photo-Optical Instrumentation Engineers
Number of pages9
ISBN (Print)0819418102
StatePublished - 1995
EventNondestructive Evaluation of Aging Structures and Dams - Oakland, CA, USA
Duration: Jun 7 1995Jun 8 1995

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherNondestructive Evaluation of Aging Structures and Dams
CityOakland, CA, USA

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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