Effects of intrinsic anisotropy on the dynamic behaviour of undisturbed loess Available to Purchase

To investigate the effects of the relative orientation between a sample's principal axes of anisotropy and the principal stress axes on the dynamic behaviour of undisturbed loess, samples with axial inclinations 30° and 90° relative to the horizontal were prepared. The effects of confining pressure and depth of soil also were examined to investigate variations in the dynamic behaviour of loess. The results showed an obvious effect of intrinsic anisotropy on the dynamic behaviour of loess. With all other conditions constant, the higher the confining pressure, the greater the dynamic stress to generate the same dynamic strain. The dynamic stresses of the 90° samples were always greater than those of the 30° samples. The effect of intrinsic anisotropy on the backbone curves was more obvious for the 2 m depth samples than for the 6 m depth samples. The damping ratio was within a certain range and initially increased as the dynamic strain increased and then gradually levelled off. The 2 m samples exhibited higher damping ratios than the 6 m samples. Finally it was found that the intrinsic anisotropy of loess might weaken the sample during the loading process and a confining pressure of 300 kPa was sufficient to nearly eliminate the effects of intrinsic anisotropy.