Abstract:

 In order to explore the drainage status and the associated impact of loess in engineering practice, strain increment ratio by triaxial test are used to investigate the shear behavior of saturated remolded loess subjected to five drainage conditions, which are no drainage condition, forced water absorption condition, free drainage condition, forced drainage condition, and partial drainage condition. The results show that, the shear behavior of saturated remolded loess are closely related to drainage conditions. In no drainage condition and forced water absorption condition, the loess samples exhibit strain softening behavior. Taken broadly, under the condition of forced water absorption, the shear expansion of the sample is forcibly exerted. In free drainage condition and forced drainage condition, the loess samples exhibit a strain hardening behavior, and the dilatancy is inhibited in the imposed drained samples. In partial drainage condition, the loess samples show a strain softening behavior or a transition state from strain softening to hardening, in which it is not only related to the strain increment ratio, but also to the void ratio. The closer the strain increment ratio is to 0, the more obvious the softening degree of the sample is. While the smaller the pore ratio of the sample, the more obvious the shear expansion trend is in the initial shear stage, and the higher the peak strength and residual strength of the sample. Besides, based on the asymptotic state equation and the stress-dilatancy relationship, the asymptotic behavior of loess and the associated dilatancy are analyzed. The result shows that the stress ratio of remolded loess at asymptotic state is negatively correlated with the sample dilatancy. 

Key words: saturated remolded loess, drainage condition, shear behavior, asymptotic state, strain increment ratio