In engineering practice, conventional triaxial tests under isotropically consolidated conditions cannot reflect the effects of various stress paths on the mechanical behavior of granite residual soil which is widely distributed in south China. To investigate the influence of the initial mean effective stress p′c and the initial stress ratio ηc on the undrained shear behavior of reconstituted granite residual soil, a series of triaxial tests under different consolidated conditions were conducted on the GDS triaxial apparatus. The test results revealed that both the initial mean effective stress and the initial stress ratio have effects on the undrained shear behavior. It was found that, for the granite residual soil in this study, under the same initial stress ratio, there would be an increase of undrained shear strength and excess pore water pressure with a higher initial mean effective stress. Besides, under the same initial mean effective stress, the higher the initial stress ratio is, the higher the undrained shear strength and the lower the excess pore water pressure would be. However, a unique critical state line can be postulated in e-p′-q space, regardless of the various initial mean effective stress and initial stress ratio.
Key words
granite residual soil /
triaxial test /
stress path /
critical state line /
3-D space
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