Abstract: Based on the framework of breakage mechanics for geological materials, a constitutive model for structured soils is proposed considering the micro-mechanism of the destructuring effects. The influence of soil structure on the mechanical behaviors is considered by employing a structural yielding surface similar to that for reconstituted soils in geometry. A damage parameter modeling the soil structure damage is used in the hardening law for structured soils. The damage parameter proposed based on the concept of sharing of stress and strain in micro-scale has tangible mechanical denotation and the cooperation of plastic volumetric strain and principal axial strain is considered in the hardening law, thus this model can properly describe the transformation of soils from intact state to reconstituted state. The validity of the proposed model is verified by predicting the mechanical behaviors of natural and artificially cemented clays in the consolidation tests and triaxial compression tests.