The stress-strain characteristics of over-consolidated clay exhibit complex mechanical characteristics with the evolution of the degree of over-consolidation. Developing a practical constitutive model can provide powerful tools for the numerical analysis of over-consolidated clay. Initially

variation of the dilatancy behavior of over-consolidated clay with degree of over-consolidation is analyzed. By introducing the over-consolidation parameters into the dilatancy relation

a simplified dilatancy equation for over-consolidated clay is established. The dilatancy equation can be integrated as a plastic potential surface. Subsequently

a practical bounding surface model is developed within the framework of bounding surface theory

utilizing the proposed dilatancy equation through a straightforward theoretical approach. Finally

the performance of the model is comprehensively validated through triaxial drained compression and extension tests at multiple levels of over-consolidation

along with undrained triaxial compression and extension tests and complex stress path tests. The results indicate that the model effectively describes the stress-strain characteristics of over-consolidated clay with the degree of over-consolidation and exhibits significant advantages in simulating volumetric deformation and pore water pressure.