Abstract:

Two groups of parameters of ellipse-parabola double yield surface model from consolidated drained triaxial tests are used to study the influences of stress-strain relationship by changing one of parameters ? , KG, n, h, m, M1, M2 and pr (keeping other parameters constant). It is found that the volume strain is evidently sensitive to the parameters of h and m. On the other hand, ? , KG and n have significant influence on the volume strain for a dilative soil but little influence for a compressive soil. Parameters of ?, KG, n, h and m have no influence on shear strength that is reflected by the double yield surface model. The parameter pr has little influence on the volume strain and shear strength. In the opposite, parameters M1 and M2 affect the volume strain and shear strength dramatically; and the smaller one determines the strength in the double yield surface model. A parameter, called sensitivity which reflects the influence of model parameter on the stress-strain relation, is defined. It is found that different parameters give quite different sensitivities; and different soils also result in different sensitivities. It is pointed out that more attention should be paid to the parameters with high sensitivity to stress-strain of soil.

Key words: ellipse-parabola double yield surface model, parameter sensitivity, stress-strain, dilatancy