Discussion of “Importance of Free Ends in Triaxial Testing”

Olson, Roy E.; Campbell, Larry M.; Lee, K. L.; Seed, H. Bolton; Turnbull, J. MacNeil; Poulos, Steve J.

doi:10.1061/jsfeaq.0000670

Cited by 7 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4 confirm that modified end platens are the most effective solution to avoid overestimation of the excess pore pressure, regardless the sample height to diameter ratio (sample 5 and sample 6). Benefits of low friction end platens on the pore pressure magnitude are well documented in the literature for classical inorganic soils (Olson & Campbell, 1964;Barden & McDermott, 1965;Duncan & Dunlop, 1968 among others), but they had never been evaluated on peats.…”

Section: Excess Pore Pressurementioning

confidence: 99%

“…Actually, part of this lack in consistency comes from the assumption of uniform stress and strain states of peat samples tested in triaxial compression, in spite of the extensive experimental effort in the 1960's addressing samples non-uniformities in standard triaxial devices (Shockley & Ahlvin, 1960;Rowe & Barden, 1964;Olson & Campbell, 1964;Bishop & Green, 1965;Barden & McDermott, 1965;Duncan & Dunlop, 1968). Among other factors related to the test protocol, end-restraint was recognised to affect the test interpretation, depending on the soil type and the soil sample geometry, and to justify a fictitious increase in the shear strength parameters determined from standard elaboration of triaxial test data.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Experimental determination of the shear strength of peat from standard undrained triaxial tests: correcting for the effects of end restraint

Muraro

Jommi

2021

Géotechnique

View full text Add to dashboard Cite

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.

show abstract

Section: Excess Pore Pressurementioning

confidence: 99%