Open AccessExperimental quantification of 3D deformations in sensitive clay during stress-probing
Author(s) -
Georgios Birmpilis,
Edward Andò,
Olga Stamati,
Stephen A. Hall,
Eleni Gerolymatou,
Jelke Dijkstra
Publication year - 2023
Publication title -
géotechnique/geotechnique
Language(s) - English
Resource type - Journals
eISSN - 1751-7656
pISSN - 0016-8505
DOI - 10.1680/jgeot.21.00114
Subject(s) - stress path , deformation (meteorology) , isotropy , stress (linguistics) , geotechnical engineering , geology , materials science , triaxial shear test , mechanics , geometry , plasticity , composite material , mathematics , physics , optics , shear (geology) , linguistics , philosophy
Unique four-dimensional (4D) deformation data are collected during drained triaxial tests on intact specimens of a natural sensitive clay. This requires the development of a miniature triaxial cell for advanced stress path testing, specifically designed for X-ray computed tomography. Salient features include the omission of a membrane, and a mounting procedure that minimises disturbance by the experimenter. Three distinct drained stress ratios are studied for pseudo-isotropic, K 0 , and highly deviatoric loading paths. The results indicate that the K 0 path shows the most uniform deformation mechanism, where the measured ratio of deviatoric and volumetric strain increments reach the stress ratio applied at boundary value level for large magnitudes of total strain. The pseudo-isotropic test also reaches a strain ratio close to η at large total strain levels; however, the deformation field is less uniform. Furthermore, the highly deviatoric stress path shows the most heterogeneous deformation fields commensurate with the applied stress ratio, although the ratio of deviatoric and volumetric strain increments falls above the η applied. The mean value of the three-dimensional spatial fields of strain corresponds well with the changes observed at boundary level, supporting prior research on drained stress-probing on clays for which there are no 4D deformation data available.