An appraisal of end conditions in advanced monotonic and cyclic triaxial testing on a range of geomaterials

Abstract

Compressing samples between rigid platens, as in triaxial testing, induce non-uniform specimen stress, strain and pore water distributions. Although well recognised historically, the effects of such platen restraints are often disregarded or overlooked when performing or interpreting monotonic and cyclic experiments. This paper presents an updated appraisal of end conditions based on laboratory experiments run on sand, glacial till, intact and puttified chalk as part of offshore piling research projects. Monotonic and cyclic triaxial tests are reported that incorporated local strain and pore pressure sensors and a range of platen configurations. New insights are reported regarding the small-to-large behaviour and undrained cyclic pore water pressure measurement.

Characterisation of soil deformation over wide strain ranges in triaxial test with high-precision stereophotogrammetry

“…The Eu,sec values are still some 30% higher in the non-lubricated case NL. This magnitude of stiffness over-estimation due to the end friction has also been noted by Liu (2018) and Vinck et al (2019) for sand. It is recommended that the mid-part measurement and end lubrication be both adopted.…”

On the influence of drained cyclic preloadings on the cyclic behaviour of Zbraslav sand

“…The undrained cyclic stages were performed with a stress-controlled approach and considering a sinusoidal waveform, with amplitude of 𝑞 amp , loading frequency of 𝑓 = 0.1 Hz and period of T = 10 seconds. The selected loading frequency of 0.1 Hz correspond to typical offshore conditions [36,[56][57][58][59][60][61][62].…”