It is well-known that the behavior of natural clay is anisotropic. One
of the reasons is that the behavior is strongly affected by the histo
ry of stress, strain, temperature and chemical reactions. This type of
anisotropy is called 'stress induced anisotropy' or 'structural aniso
tropy'. On the other hand, the behavior of clay also strongly depends
on the current stress state. The current stress sensitivity is one of
the salient features of granular materials. An anisotropic stress stat
e causes results in anisotropic and pseudo-anisotropic deformation beh
avior. The objective of the present paper is to propose a constitutive
model for clay to describe the rate-dependent anisotropic and/or the
current stress induced pseudo-anisotropic behavior of clay based on a
transformed stress tensor. It is shown that the proposed constitutive
model is noncoaxial and applicable to explain the current stress induc
ed pseudo-anisotropy, the effect of the intermediate stress dependency
of the soil behavior and the deviatoric flow rule. In addition, an ob
jective formulation of the constitutive model for large deformations i
s discussed.