Abstract: Within the Disturbed State Concept framework, the relatively intact state is characterized by a linear elastic incremental matrix. Conversely, the fully adjusted state is represented by an elasto-plastic incremental matrix synthesizing the triple-shear failure stress ratio for unsaturated soils, unified hardening parameter, and modified Cam-Clay model. Substitution of these state characterizations into the incremental disturbance function equation and subsequent three-dimensional formulation yields the developed triple-shear structured constitutive model for over-consolidated unsaturated clays. Artificial structured soil was fabricated from Jiangxi red clay through the treatment with bacterial suspension and cementation solution. This technique operates on the principle of Microbially Induced Calcite Precipitation (MICP), whereby biochemical reactions generate calcite bonds between cement soil particles. Unsaturated triaxial consolidated drained testing was performed under controlled overconsolidation ratios and matric suctions using a GDS apparatus. Model validation against experimental triaxial data demonstrates close alignment between simulated and measured stress-strain responses. The model accurately replicates key over-consolidated soil behaviors, including strain softening, dilatancy, and contraction, confirming its validity. True triaxial numerical simulations confirm the model’s capability to capture the influence of the intermediate principal stress coefficient. The peak deviatoric stress increases with higher values of the intermediate principal stress coefficient. The constitutive model is verified to effectively represent the mechanical behavior of over-consolidated unsaturated structured clays under true triaxial stress paths.