Effects of initial deviatoric stress ratios on dynamic shear modulus and damping ratio of undisturbed loess in China

The foundation soil masses are always in complex initial stress states. However, the traditional study did not take account of the effects of complex initial stress state parameters on the dynamic characteristic parameters of structural loess. This study investigated the influences of initial deviatoric stress ratios, one of the complex initial stress state parameters, on dynamic shear modulus and damping ratio of undisturbed loess in China through laboratory testing. The results show that the effects of initial deviatoric stress ratios on the dynamic shear stress and strain relations are significant. In addition, the dynamic shear modulus and damping ratio are also influenced by the initial deviatoric stress ratios. The capacities of resisting shear deformations of undisturbed loess under high initial deviatoric stress ratios are weak, while the capacities of consuming dynamic energies are strong. The anti-seismic design and dynamic response analysis of practical engineering projects should take into consideration the effects of initial deviatoric stress ratios.

► Initial deviatoric stress ratios influence the changing laws of dynamic shear strains with time.
► Initial deviatoric stress ratios have significant effects on the dynamic shear stress and strain relations.
► The capacity of resisting shear deformation of undisturbed loess decreases under the effects of high deviatoric stress ratios.
► Loess could consume more energy under higher deviatoric stress ratios compared with that under lower deviatoric ratios.