Effects of Inherent Fabric Anisotropy on the Cyclic Liquefaction Behavior of Sand under Constant Volumetric Expansion Rates

Abstract Although cyclic liquefaction of sand is commonly associated with undrained conditions, the expansive drainage condition represents a more appropriate scenario for layered foundations in situ. Additionally, sand deposited in a natural state exhibits an inherent fabric anisotropy, which significantly affects its liquefaction behavior. In this study, a series of cyclic simple shear tests with different volumetric expansion rates and bedding plane angles are conducted. The effects of different densities and cyclic amplitudes are also taken into consideration. The simulation results show that the effect of bedding plane angle on liquefaction resistance is not monotonic: the liquefaction resistance reaches a minimum at 45° as the bedding plane angle increases from 0° to 90°. In contrast, volumetric expansion significantly reduces the liquefaction resistance even if a small volumetric expansive strain (| ε v | < 0.5%) is imposed. Furthermore, the contact-normal-based fabric tensor is used to quantify the evolution of the internal load-bearing structure of granular specimens. The macroscopic observations are well explained by analyzing the interaction between external loading and internal fabric evolution.