Experimental determination of the shear strength of peat from standard undrained triaxial tests

Correcting for the effects of end restraint

Journal Article (2021)
Author(s)

S. Muraro (TU Delft - Geo-engineering)

C. Jommi (Politecnico di Milano, TU Delft - Geo-engineering)

Geo-engineering
Copyright
© 2021 S. Muraro, C. Jommi
DOI related publication
https://doi.org/10.1680/jgeot.18.P.346
More Info
expand_more
Publication Year
2021
Language
English
Copyright
© 2021 S. Muraro, C. Jommi
Geo-engineering
Issue number
1
Volume number
71
Pages (from-to)
76-87
Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Abstract

Conventional triaxial tests on peats are strongly criticised due to the very high shear strength parameters obtained from standard data elaboration, leading to unrealistic factors of safety when used in geotechnical design and assessment. Various operational approaches have been proposed in the literature to overcome this difficulty; however, they seem to lack consistent mechanical background. Some of the issues related to the shear strength evaluation of peats from triaxial tests come from the non-uniform stress and strain states developing in the samples well before failure is attained, due to end restraint effects. Undrained triaxial compression tests were performed on reconstituted peat to examine the influence of end restraint on the deviatoric stress, excess pore pressure and deviatoric strain response. Samples were tested with standard rough end platens and with modified platens to reduce the friction between the sample and bottom and top caps. Four different initial height-to-diameter ratios were examined, to reduce the consequences of rough end platens on the sample response. The results indicate that end restraint contributes dramatically to overestimating the shear strength of peat, due to the increase in both the calculated deviatoric stress and the measured excess pore pressure at the bottom of the sample. Suggestions are given to quantify the influence of end restraint in the interpretation of standard data, in an attempt to suggest viable procedures to determine more reliable effective and undrained shear strength parameters from standard triaxial tests.

Files

Postprint_request_ID_86458662.... (pdf)
(pdf | 1.72 Mb)
- Embargo expired in 04-12-2021
License info not available