Abstract A tensor-based approach is adopted to investigate the evolution of stress variability within granular media based on DEM simulations of both cyclic and static liquefactions. The bulk stress dispersion is evaluated using the effective variance of the entire stress tensor field and the local stress fluctuation is quantified by the Euclidean distance between the stress tensor of individual particles and the global stress tensor. The orientation discrepancies between the local stress tensor and global fabric tensor, and between the local and global stress tensors are examined by their joint invariants. We observe that the bulk stress dispersion decreases but the discrepancy of local stress fluctuation increases upon liquefaction. The initially deviatoric stress-dominated stress variability gradually becomes hydrostatic stress-dominated, and returns to deviatoric stress-dominated again after liquefaction. The liquefaction process is characterized by the degradation of coaxiality between the local stress tensor and the global fabric tensor and that between the local and global stress tensors. There exists a range of threshold values for such coaxiality, below which liquefaction occurs. Particles with coaxiality higher than the threshold value and particles with coaxality lower than the threshold value exhibit different roles in sustaining external loads. However, the discrepancy becomes neutral upon liquefaction.

中文翻译：

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表征液化后颗粒样品内的应力变化

摘要 基于循环液化和静态液化的 DEM 模拟，采用基于张量的方法研究颗粒介质内应力变化的演变。体应力分散使用整个应力张量场的有效方差进行评估，局部应力波动由单个粒子的应力张量与全局应力张量之间的欧几里德距离量化。局部应力张量和全局结构张量之间以及局部应力张量和全局应力张量之间的方向差异通过它们的联合不变量来检查。我们观察到体积应力分散降低但局部应力波动的差异在液化时增加。最初以偏应力为主的应力变异逐渐变为静水应力为主，并在液化后再次回到偏应力主导。液化过程的特点是局部应力张量与整体织物张量之间以及局部应力张量与整体应力张量之间的同轴度下降。这种同轴度存在一定范围的阈值，低于该范围会发生液化。同轴度高于阈值的颗粒和同轴度低于阈值的颗粒在承受外部载荷方面表现出不同的作用。然而，该差异在液化时变为中性。这种同轴度存在一定范围的阈值，低于该范围会发生液化。同轴度高于阈值的颗粒和同轴度低于阈值的颗粒在承受外部载荷方面表现出不同的作用。然而，该差异在液化时变为中性。这种同轴度存在一定范围的阈值，低于该范围会发生液化。同轴度高于阈值的颗粒和同轴度低于阈值的颗粒在承受外部载荷方面表现出不同的作用。然而，该差异在液化时变为中性。