  It has been proposed recently a new incremental modelling to describe the
mechanics of soil. It is based on two parameters called the pseudo Young
modulus E=1/Co and the pseudo Poisson coefficient n, which both evolve during
compression. Evolution of n is known since it shall fit the Rowe's law of
dilatancy, but Co has to be evaluated from experiment. In this paper we
proposed a way to evaluate the Co variation from other mechanical modelling.
The way cyclic behaviour of drained sample can be modelled is also described.
