Some innovative developments of TDR technology for geotechnical monitoring

Chih Ping Lin, Chih Chung Chung, Shr Hung Tang, Chun Hung Lin

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations


Up-hole time domain reflectometry (TDR) devices that interrogate passive mechanical transducers are advantageous for engineering monitoring in situ. This technology is based on transmitting an electromagnetic pulse through a coaxial cable connected to a sensing waveguide and watching for reflections of this transmission due to changes in characteristic impedance along the waveguide. Depending on the design of the wave guide and analysis method, the reflected signal can be used to monitor various engineering parameters. This paper introduces some recent developments to improve the understanding and extend the usefulness of TDR technology. TDR waveguides for engineering monitoring are grouped into three categories according to the sensing principle, namely interface type, crimp type, and dielectric type. New design concepts and data reduction procedures for each type of waveguide are introduced. These developments improve and lead to a variety of transducers, such as water level, deformation, rainfall, scouring, soil moisture, sediment concentration, and electrical conductivity. The versatility and merits of TDR are highlighted by examples of hybrid economical TDR monitoring systems composed of a single TDR device and multiple sensing waveguides.

Original languageEnglish
Title of host publicationFMGM 2007 - Proceedings of the 7th International Symposium on Field Measurments in Geomechanics
Number of pages1
StatePublished - 2007
Event7th International Symposium on Field Measurements in Geomechanics, FMGM 2007 - Boston, MA, United States
Duration: 24 Sep 200727 Sep 2007

Publication series

NameGeotechnical Special Publication
ISSN (Print)0895-0563


Conference7th International Symposium on Field Measurements in Geomechanics, FMGM 2007
Country/TerritoryUnited States
CityBoston, MA


  • Geotechnical monitoring
  • Time domain reflectometry


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