Seismic Response Analysis of Liquefiable Sandy Ground Considering Inherent Anisotropy’s Influence

Consideration of inherent anisotropy is crucial to gaining an improved understanding of the behavior of granular materials. One of the authors examined inherent anisotropy’s effect on the seismic behavior of ground through dynamic centrifuge model tests and revealed that a sandy level ground deposited at a higher angle is more susceptible to liquefaction. In the present paper, seismic response analyses are performed on the liquefiable sandy ground considering inherent anisotropy and their results are compared with the experiment. For modeling the sandy ground, a strain space multiple mechanism model is used; the model has been expanded for describing sand behavior associated with inherent anisotropy, by introducing three anisotropic parameters (a₁, a₂, and θ_o). The seismic response analyses with no consideration for permeability anisotropy show that it is difficult to accurately simulate the deposition angle dependency in the experiment, even though the additional anisotropic parameters are employed. This study demonstrates that considering anisotropic permeability, which may depend on the deposition angle, is required as well as the additional three parameters for properly capturing the liquefaction behavior of sandy ground associated with inherent anisotropy.