Abstract: The mathematical model for structured soil is a key problem of soil mechanics in twenty-first century. Soil microstructure is the main reason which causes the differences between natural and remolded soils. Stress structural parameter and strain structural parameter were introduced to describe the change of microstructure. At the same time strain structural parameter were introduced into the isotropic consolidation process to describe the effect of spherical stress on structural soil in the process of isotropic consolidation and shearing, which realized the description for the whole process of triaxial shear tests. Modified Cambridge model can make an accurate description for normally consolidated remolded clay in the triaxial compression tests, but failed to make the same precision for overconsolidated clays and intact soil, which had the structural characteristics. Then the strain and stress structural macro parameters were introduced into the modified Cambridge model to achieve structurization. The parameters determination methods for structured modified Cambridge model were similar with the conventional modified Cambridge model parameters determination, but more than the relationships between spherical stress and strain, deviatoric stress and soil structural generalized shear strain. Through numerical simulation, the structural modified Cambridge model well reflected the structural evolution of the intact soil, and described the whole failure process of structure on a variety of stress paths for intact clay in Haikou.

Key words: stress structural parameter, strain structural parameter, modified Cambridge model, red clay in Haikou