Evaluation of suction measurement by the tensiometer and the axis translation technique

S. D N Lourenço, D. G. Toll, C. E. Augarde, D. Gallipoli, F. D. Evans, G. M. Medero

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

    1 Citation (Scopus)

    Abstract

    The axis translation technique is a well-established method for imposing values of suction in unsaturated soil samples. High-suction tensiometers are more recently developed devices used for measuring pore water pressures in soils, including negative pore water pressures (i.e. suctions) below absolute zero. Both these techniques are comparable in terms of the suction range in which they operate. In this work a tensiometer has been used to measure suction values imposed by the axis translation technique in kaolin samples inside a pressure plate and a triaxial cell. The tensiometer has been kept in contact with the soil sample to track pore water pressure variations throughout the duration of the tests. The suctions measured by the tensiometer have been compared to those imposed by the axis translation technique and it was found that the suction measured by the tensiometer was always smaller than that imposed. Two scenarios are proposed to explain this. The first scenario considers the presence of water inside and below the high air entry value ceramic plate whereas the second one hypothesises the lack of equilibrium in terms of soil water content when suction is measured. The latter scenario seems to be supported by the evidence in the literature of equilibration times for pressure plate tests that are significantly longer than those reported for the present testing programme. Implications of both scenarios for laboratory testing are discussed. © 2008 Taylor & Francis Group, London.

    Original languageEnglish
    Title of host publicationUnsaturated Soils: Advances in Geo-Engineering - Proceedings of the 1st European Conference on Unsaturated Soils, E-UNSAT 2008
    Pages213-218
    Number of pages6
    Publication statusPublished - 2008
    Event1st European Conference on Unsaturated Soils - Durham, United Kingdom
    Duration: 2 Jul 20084 Jul 2008

    Conference

    Conference1st European Conference on Unsaturated Soils
    Abbreviated titleE-UNSAT 2008
    CountryUnited Kingdom
    CityDurham
    Period2/07/084/07/08

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  • Cite this

    Lourenço, S. D. N., Toll, D. G., Augarde, C. E., Gallipoli, D., Evans, F. D., & Medero, G. M. (2008). Evaluation of suction measurement by the tensiometer and the axis translation technique. In Unsaturated Soils: Advances in Geo-Engineering - Proceedings of the 1st European Conference on Unsaturated Soils, E-UNSAT 2008 (pp. 213-218)