On Jaky Constant of Oedometers, Rowe’s Relation and Incremental Modelling


P. Evesque: Lab MSSM, UMR 8579 CNRS, Ecole Centrale Paris, 92295 Châtenay-Malabry, France, evesque@mssmat.ecp.fr


Abstract: It is recalled that stress-strain incremental modelling is a common feature of most theoretical description of the mechanical behaviour of granular material. An other commonly accepted characteristics of the mechanical behaviour of granular material is the Rowe’s relation which links the dilatancy K= -v/1 to the stress ratio 1/3 during a 2=3=cst test , i.e. s1/s3=(1+M)(1+K). We combine these two features and extract an incremental pseudo-Poisson coefficient which varies with 1/3 .  We solve the oedometric-test case, starting from isotropic sample and stress, for which s1 is increased continuously. It is found that the 1/3 ratio evolves towards an asymptotic value ko which depends on the friction angle j only. It is shown that this asymptotic value ko compares well with the experimental fit known as the Jaky constant i.e. kJaky= 1-sinj , where j  is the friction angle.


poudres & grains 6, 1-9 ( août-septembre 1999)