The liquefaction phenomena of sands have been studied by many researchers to date. Laboratory element tests have revealed key factors that govern liquefaction phenomena, such as relative density, particle size distribution, and grain shape. However, challenges remain in quantifying inherent anisotropy and in evaluating its impact on liquefaction phenomena. This contribution explores the effect of inherent anisotropy on the mechanical response of granular materials using the discrete element method. Samples composed of spherical particles are prepared which have approximately the same void ratio and mean coordination number (CN), but varying degrees of inherent anisotropy in terms of contact normals. Their mechanical responses are compared under drained and undrained triaxial monotonic loading as well as under undrained cyclic loading. The simulation results reveal that cyclic instability followed by liquefaction can be observed for loose samples having a large degree of inherent anisotropy. Since a sample having initial anisotropy tends to deform more in its weaker direction, leading to lower liquefaction resistance, a sample having an isotropic fabric potentially exhibits the greatest liquefaction resistance. Moreover, the effective stress path during undrained cyclic loading is found to follow the instability and failure lines observed for static liquefaction under undrained monotonic loading. From a micromechanical perspective, the recovery of effective stress during liquefaction can be observed when a threshold CN develops along with the evolving induced anisotropy. Realising that the conventional index of the anisotropic degree (a) is not effective when the CN drops to almost zero during cyclic liquefaction, this contribution proposes an alternative index, effective anisotropy (a×CN), with which the evolution of induced anisotropy can be tracked effectively, and common upper and lower bounds can be defined for both undrained monotonic and cyclic loading tests.

迄今为止，许多研究人员已经研究了沙子的液化现象。实验室元素测试揭示了控制液化现象的关键因素，例如相对密度、粒度分布和颗粒形状。然而，在量化固有各向异性和评估其对液化现象的影响方面仍然存在挑战。该贡献使用离散元方法探索了固有各向异性对颗粒材料机械响应的影响。制备由球形颗粒组成的样品，它们具有大致相同的空隙率和平均配位数（CN)，但在接触法线方面存在不同程度的固有各向异性。它们在排水和不排水三轴单调载荷以及不排水循环载荷下的机械响应进行了比较。模拟结果表明，对于具有大量固有各向异性的松散样品，可以观察到循环不稳定随后液化。由于具有初始各向异性的样品倾向于在其较弱的方向上更多地变形，导致较低的液化阻力，因此具有各向同性织物的样品可能表现出最大的液化阻力。此外，发现不排水循环加载期间的有效应力路径遵循在不排水单调加载下静态液化观察到的不稳定性和失效线。从微观力学的角度来看，CN随诱发各向异性的演变而发展。认识到在循环液化过程中CN下降到几乎为零时，各向异性程度的常规指标 ( a ) 无效，该贡献提出了一个替代指标，有效各向异性( a×CN )，通过该指标可以得到诱导各向异性的演变。有效地跟踪，并且可以为不排水单调和循环加载测试定义共同的上限和下限。