Abstract: In this paper geomaterials are conceptualized as binary medium consisting of bonded blocks and weakened cells which are idealized as elastic-brittle element and hardening elastic-plastic element respectively. Based on the homogenization theory of heterogeneous materials, a generalized stress-strain relationship expressed in incremental form is derived. The model contains two sets of structural parameters whose evolution laws can be determined by means of “try and error” method, i.e, breakage parameter and stress concentration coefficient of elastic-brittle element. Finally a structural clay and a sandstone specimen are taken as two examples to prove the applicability of the suggested model.