Abstract：The extended failure stress ratio connecting with the different stress state and the cohesion is given out based on the triple-shear unified failure criterion and coordinate translation for the saturated over-consolidated clay, in order to overcome the shortcomings of the original sub-loading yield surface modified cam-clay model with the definite failure stress ratio without considering the soil cohesion, which can't reflect the practical differences of strength properties under different stress states and cohesions for soils. The advantage is that the extended failure stress ratio could show the practical effects of different stress states acting on the saturated over-consolidated clay with different cohesions better. Depending on the viewpoint above, a new triple-shear elasto-plastic constitutive model for the saturated over-consolidated clay is set up. Its features are that it can describe the effects of intermediate principal stress, rang changes of stress, difference between tension and compression and different cohesions. In addition, the ABAQUS is developed secondly based on the new constitutive model and the mechanical properties are simulated under the true and the conventional triaxial tests in the drainage and the undrained conditions for the saturated over-consolidated clay. Comparisons between the numerical simulations and experimental results under conventional triaxial tests show that the proposed model could reflect the changes of deformations, shear dilatations and pore water pressures for the saturated over-consolidated clay with different OCR.
2017, Vol. 38 
