It is challenging to understand the stress wave response of cohesionless particle assemblies including compression and shear wave velocities ($V_p$ and $V_s$) due to complicated particle-scale interactions particularly during a loading process. This contribution adopts the discrete element method to simulate triaxial compression experiments using spherical particles. Four samples are isotropically confined at various initial packing densities and then sheared monotonically up to the critical state. Small-amplitude wave propagation simulation is performed during shearing along the axis of loading. The results reveal that $V_p$ is affected by the major principal stress and the coordination number contributing to the vertical direction rather than horizontal direction, while $V_s$ is more influenced by the geometric mean stress and the mean coordination number. The wave velocity ratio ($V_p$/$V_s$) is well correlated with the fabric anisotropy, having a linear relationship. This enables prediction of microscopic change in fabric from macroscopic wave velocity values. Besides, a material-specific relationship between stress levels and wave velocities is found at the critical state with a unique fabric anisotropy, independent of initial packing. $V_s$ in the isotropic state is found to be always larger that at the critical state under an equivalent stress level.

理解无内聚粒子组件的应力波响应（包括压缩波和剪切波速度）具有挑战性（$V_p$ 和 $V_s$）是由于复杂的粒子尺度相互作用，尤其是在加载过程中。该贡献采用离散元素方法来模拟使用球形粒子的三轴压缩实验。将四个样品各向同性地限制在各种初始填充密度下，然后单调剪切至临界状态。在沿载荷轴的剪切过程中执行小振幅波传播模拟。结果表明$V_p$ 受主要主应力和构成垂直方向而不是水平方向的配位数的影响，而 $V_s$受几何平均应力和平均配位数的影响更大。波速比（$V_p$/$V_s$）与织物各向异性密切相关，具有线性关系。这使得能够根据宏观波速值预测织物的微观变化。此外，在临界状态下，应力水平与波速之间存在特定于材料的关系，具有独特的织物各向异性，而与初始填充无关。$V_s$ 在同等应力水平下，各向同性状态的应力总是大于临界状态的应力。