532 533The unified disturbed concept (DSC) for constitutive modeling of geologic materials and interfaces (joints) is presented with details including the relative intact (RI) state, fully adjusted (FA) state and disturbance. Attention is given to model parameters based on triaxial, multiaxial and interface tests, and validations at specimen level. The DSC is implemented in 2- and 3-D finite element procedures which are used to predict behavior of wide range problems including comparisons with field and laboratory simulated tests. The DSC is considered to be a unique and versatile procedure for modeling behavior of engineering materials and interfaces.