Investigation and Experimental Verification of a Constitutive Model Considering Structural Characteristics of Soft Clay

The mechanical behaviors of structured soft clay in consolidation tests and undrained triaxial shear tests were investigated, revealing evident structural properties of undisturbed Ningbo clay. Based on the experimental results, the limitation of the original constitutive model in simulating the structural properties of clay were discussed, and the evolution rule for the structure in the original constitutive model was revised. The parameter A that represented the ratio of plastic deviatoric strain to plastic volumetric strain was proposed to account for the distinct differences in the plastic deviatoric and volumetric strains on structural degradation. This modification enhances the ability of the constitutive model to accurately simulate the mechanical behaviors of structured soft clay. The performance of the modified constitutive model was verified by the consolidation and triaxial shear tests. Furthermore, the structure degradation of undisturbed Ningbo clay was investigated. For undisturbed Ningbo clay, the plastic volumetric strain plays a major role in causing progressive structural degradation compared to the plastic deviatoric strain.