摘要
In this paper,the variation in structural yielding characteristic of the loess from Lanzhou city and the main affecting factors were analyzed via triaxial test.The results show that shear behavior of the unsaturated loess varied with degree of saturation,dry density and confining pressure.The loess with higher dry densities was of strain-softening behavior,while those with lower dry densities had strain-hardening nature.For the former,its shear behavior changed at saturation degree of 70%.The structural yielding characteristics were weakened with increase in saturation degree,with which structural yielding stress for the loess with higher and lower dry densities decreased nonlinearly and linearly.On the other hand,structural yielding characteristics of loess with different saturation degree were strengthened with the increase in confining pressure,dry density and clay content.Particularly,the structural yielding stress of the loess with higher and lower dry densities had nonlinear and linear correlations with confining pressure respectively,and increased nonlinearly with dry density.