Abstract: A thermomechanical framework for modeling soils ispresented in this paper. The essence of the theory is to establishconstitutive relationships by using free energy and dissipation functionsthrough a fixed framework and procedure. The theory of internalvariables and the methodof Legendre transformation to determine the relationships among free energyfunctions as well as the relationship between dissipation and yield functionsare briefly discussed, the steps of formulating constitutive equationswithin this framework are also presented. The significance of soilconstitutive relationships and its relation with applications arediscussed.