2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/26631Experimental data from axially symmetric compression test at constant mean pressure p on kaolinite clay are used to study the validity of an "isotropic" modelling as a function of the overconsolidation ratio (OCR).The isotropic assumption is found to be quite good for 2<OCR<3 and/or in the range of small deformation for OCR>4. For very large OCR (OCR >10), anisotropic response is observed at few percents of axial deformation. Relation with anisotropic distribution of local forces is made. Pacs # : 5.40 ; 45.70 ; 62.20 ; 83.70.Fn6 pages + 1 page, 1 figureSoft Condensed Mattertext