Liquefaction resistance of sand can be either increased or reduced due to an undrained cyclic pre-shearing depending on the degree of pre-shearing, which hinders a better prediction of liquefaction potential to be established. The mechanism of such changes in liquefaction resistance has been poorly understood. This contribution aims to gain micromechanical insights into pre-shearing effects on liquefaction resistance of sand using discrete element method (DEM) simulations. In particular, effects of particle shape and initial anisotropy on liquefaction resistance are investigated. The simulation results from samples consisting of non-spherical particles with an initial anisotropy can qualitatively capture the mechanical responses observed in equivalent laboratory experiments. The samples which yielded a qualitative agreement with the laboratory results are further analyzed micromechanically, and the relationships between liquefaction resistance and some microscopic parameters before cyclic loading are discussed. Microscopic analyses reveal that mean mechanical coordination number is well correlated with liquefaction resistance, whereas liquefaction resistance is less sensitive to anisotropy in particle orientation induced by pre-shearing.

由于不排水的循环预剪切，取决于预剪切的程度，可以提高或降低砂子的抗液化性，这妨碍了对要建立的液化潜力的更好预测。耐液化性变化的机理了解甚少。该贡献旨在使用离散元方法（DEM）模拟获得有关预剪切作用对砂土抗液化性的微观力学见解。特别地，研究了颗粒形状和初始各向异性对抗液化性的影响。由具有初始各向异性的非球形颗粒组成的样品的模拟结果可以定性地捕获在等效实验室实验中观察到的机械响应。对与实验结果定性吻合的样品进行了微机械分析，并讨论了循环加载前的抗液化性与一些微观参数之间的关系。显微分析表明，平均机械配位数与抗液化性密切相关，而抗液化性对预剪切诱导的颗粒取向各向异性较不敏感。