Abstract: Previous research on liquefaction flow characteristic indicates that liquefied sand can be modeled as shear thinning non-Newtonian fluid. A flow constitutive equation of liquefied sand is established by using a power function relationship between the shear stress and the shear strain rate. A simplified method for large deformation analysis of liquefied sand is established through implementing the flow constitutive equation into the FLAC3D package. A case study of gradient foundation is performed by applying the proposed method to validate the constitutive model. The numerical results show that the displacement of gradient foundation can be described by a sinusoidal curve, which is in good agreement with the theoretical solution of Prof. Towhata. Parametric sensitivity analyses are conducted to investigate the influences on the deformation of liquefied sand from variables including the liquefaction layer slope, consistency coefficient, flow index and elastic parameters. The results indicate that the liquefaction deformation develops with the increase of the slope of the liquefied layer. What’s more, the consistency coefficient and the flow index of the liquefied sand have significant effect on the deformation of liquefied sand; while influence from the elastic parameters is inconsiderable. A further research on these parameters should be conducted in engineering practice.

Key words: sand liquefaction, flow deformation, non-Newtonian fluid, large deformation, calculating method