Calibration of a TDR probe in an expansive soil

Stephen Fityus, K. Rajkai

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

1 Citation (Scopus)

Abstract

The measurement of soil water content in situ is not straightforward. Capacitance methods such as Time Domain Reflectometry (TDR) can be used to estimate the volumetric water content in situ using a passive "probe" which is embedded in a soil and connected via a cable to a signal processor/ recorder. In this study, a systematic series of laboratory measurements was undertaken to determine the relationship between true volumetric water content, gravimetric water content and TDR measured water content in uncracked Maryland clay. The results show not only that the TDR measured water contents differ from the true volumetric water contents, but that the TDR is potentially relatively insensitive over a significant interval of mid-range water contents in uncracked clay. Tests to estimate the effect on measurements from the presence of cracks of different width found that errors increase steadily as crack width increases. The study also determined that the measurements are relatively insensitive to misalignment of the waveguide prongs.

Original languageEnglish
Title of host publicationUnsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils
Pages653-657
Number of pages5
Volume1
Publication statusPublished - 2011
Event5th International Conference on Unsaturated Soils - Barcelona, Spain
Duration: Sep 6 2010Sep 8 2010

Other

Other5th International Conference on Unsaturated Soils
CountrySpain
CityBarcelona
Period9/6/109/8/10

Fingerprint

expansive soil
time domain reflectometry
calibration
water content
probe
soil
clay
crack
capacitance
soil water content
cable
soil water

ASJC Scopus subject areas

  • Soil Science

Cite this

Fityus, S., & Rajkai, K. (2011). Calibration of a TDR probe in an expansive soil. In Unsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils (Vol. 1, pp. 653-657)

Calibration of a TDR probe in an expansive soil. / Fityus, Stephen; Rajkai, K.

Unsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils. Vol. 1 2011. p. 653-657.

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

Fityus, S & Rajkai, K 2011, Calibration of a TDR probe in an expansive soil. in Unsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils. vol. 1, pp. 653-657, 5th International Conference on Unsaturated Soils, Barcelona, Spain, 9/6/10.
Fityus S, Rajkai K. Calibration of a TDR probe in an expansive soil. In Unsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils. Vol. 1. 2011. p. 653-657
Fityus, Stephen ; Rajkai, K. / Calibration of a TDR probe in an expansive soil. Unsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils. Vol. 1 2011. pp. 653-657
@inproceedings{286b16dbe50d4ac3aa7f5ed5909a5683,
title = "Calibration of a TDR probe in an expansive soil",
abstract = "The measurement of soil water content in situ is not straightforward. Capacitance methods such as Time Domain Reflectometry (TDR) can be used to estimate the volumetric water content in situ using a passive {"}probe{"} which is embedded in a soil and connected via a cable to a signal processor/ recorder. In this study, a systematic series of laboratory measurements was undertaken to determine the relationship between true volumetric water content, gravimetric water content and TDR measured water content in uncracked Maryland clay. The results show not only that the TDR measured water contents differ from the true volumetric water contents, but that the TDR is potentially relatively insensitive over a significant interval of mid-range water contents in uncracked clay. Tests to estimate the effect on measurements from the presence of cracks of different width found that errors increase steadily as crack width increases. The study also determined that the measurements are relatively insensitive to misalignment of the waveguide prongs.",
author = "Stephen Fityus and K. Rajkai",
year = "2011",
language = "English",
isbn = "9780415604291",
volume = "1",
pages = "653--657",
booktitle = "Unsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils",

}

TY - GEN

T1 - Calibration of a TDR probe in an expansive soil

AU - Fityus, Stephen

AU - Rajkai, K.

PY - 2011

Y1 - 2011

N2 - The measurement of soil water content in situ is not straightforward. Capacitance methods such as Time Domain Reflectometry (TDR) can be used to estimate the volumetric water content in situ using a passive "probe" which is embedded in a soil and connected via a cable to a signal processor/ recorder. In this study, a systematic series of laboratory measurements was undertaken to determine the relationship between true volumetric water content, gravimetric water content and TDR measured water content in uncracked Maryland clay. The results show not only that the TDR measured water contents differ from the true volumetric water contents, but that the TDR is potentially relatively insensitive over a significant interval of mid-range water contents in uncracked clay. Tests to estimate the effect on measurements from the presence of cracks of different width found that errors increase steadily as crack width increases. The study also determined that the measurements are relatively insensitive to misalignment of the waveguide prongs.

AB - The measurement of soil water content in situ is not straightforward. Capacitance methods such as Time Domain Reflectometry (TDR) can be used to estimate the volumetric water content in situ using a passive "probe" which is embedded in a soil and connected via a cable to a signal processor/ recorder. In this study, a systematic series of laboratory measurements was undertaken to determine the relationship between true volumetric water content, gravimetric water content and TDR measured water content in uncracked Maryland clay. The results show not only that the TDR measured water contents differ from the true volumetric water contents, but that the TDR is potentially relatively insensitive over a significant interval of mid-range water contents in uncracked clay. Tests to estimate the effect on measurements from the presence of cracks of different width found that errors increase steadily as crack width increases. The study also determined that the measurements are relatively insensitive to misalignment of the waveguide prongs.

UR - http://www.scopus.com/inward/record.url?scp=84859977025&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84859977025&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:84859977025

SN - 9780415604291

VL - 1

SP - 653

EP - 657

BT - Unsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils

ER -