ANALYSIS OF STRESS-STRAIN BEHAVIOR OF CLAY ALONG TYPICAL STRESS PATHS IN PRACTICAL PROJECTS

The Mohr-Coulomb model, the modified Cam-clay model UH model were used to model the stress-strain relationships under the triaxial compression, extension and compression with decreasing principal stress conditions.The result predicted by the Mohr-Coulomb model, as a perfect elasto-plastic model, was elastic stress-strain relationship when stress point was in yield surface and is elasto-plastic stress-strain relationship with the constant stress and infinite increasing deformation when stress point was on yield surface under the triaxial compression condition. The modified Cam-clay model could be used to predict the behavior of the normally consolidated clay in the triaxial test well, but it over-estimated the strength of clay under the extension condition. The UH model for the normally consolidated clay and over-consolidated clay had the same parameters as those in the modified Cam-clay model. For the normally consolidated clay, the UH model was the same as the modified Cam-clay model. By applying the transformed stress method based on SMP criterion, the UH model could describe the property of clay in threedimension stress space.