In this paper the incremental nonlinear models are generally discussed

the correlation of this sort of models with others and the difference between them are interpreted

and some basic concepts are clarified. We presented a nonlinear dilatant stress-strain model for soil

which is referred to as KKG model for the sake of simplicity. The experimental results of a sand sample are used to determine the moduli for the following models KKG

KG (the deformation model)

and Eν (elastoplastic model) respectively. The comparison of the calculation values of these models with the associated experimental results shows good fittings and prediction of KKG model

and its good simulation of soil dilatant behaviour in particular. The predicted pore pressure and effective stress path have a reasonably good agreement with observed results as well.