基于双重塑性机制，即剪切滑移和加载湿陷机制，及毛细滞回和变形间的耦合作用，提出了一个适用于非饱和黏土的状态相关本构模型。建立了该模型的隐式积分算法，并处理了双重固相屈服面交点处的应力积分问题。考虑了吸力与应力间的关系，推导了本构关系的一致性切线模量。最后，利用该模型预测了一组非饱和黏土的三轴试验，以此反映模型的描述能力；对比了不同应变步长下应变控制试验的计算结果，并以此验证算法的收敛性和准确性；利用有限元程序平台U_DYSAC2计算了二维情况下非饱和土地区地基固结问题，从而验证所得一致性切线模量的有效性。

A state-dependent constitutive model for unsaturated clays is proposed based on the double plastic mechanisms (i.e., shear sliding and loading collapse mechanisms), and the coupling between hydraulic hysteresis and stress-strain behavior. In the proposed model, the stress integration at the intersection of two solid phase yield surfaces is addressed using an implicit integration algorithm. The consistent tangent matrix of constitutive model is explicitly derived by considering the relationship between stress and suction. Finally, the numerical simulations of triaxial tests on unsaturated clay are carried out to demonstrate the abilities of the constitutive model. The calculated results of strain-controlled tests on unsaturated soils with different step sizes are compared to demonstrate the convergence and accuracy of the implicit algorithm. The two-dimensional ground consolidation of unsaturated soils is analyzed using the U_DYSAC2 program to demonstrate the validity of the consistent tangent matrix.