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)