The tunnel face stability is closely related to the migration behavior and clogging mechanism of the slurry particles in granular soils, which is not yet fully understood. In this study, the coupled computational fluid dynamics–discrete element method (CFD–DEM) is adopted to investigate the infiltration behavior of slurry at the particle scale. The full Johnson–Kendall–Roberts (JKR) contact model describing interparticle behavior that accounts for cohesion present even when particles are microseparated after collisions is adopted for clay‐clay or clay‐sand particles and the Hertz–Mindlin model is used for sand‐sand particles. Through simulations, the mechanism of the slurry particle's blockage is identified as physical, frictional and cohesive modes, and slurry particle migration usually undergoes the process of aggregation‐destruction‐migration‐reassembly. Meanwhile, the influences of pressure, cohesive force, and particle shape on infiltration are also analyzed. The results indicate that high pressure lengthens the infiltration path and increases the infiltration rate. The increase in cohesion enhances the effective clogging of the sand column by the slurry, and particles with smaller sphericity are more likely to clog in the sand column. These findings may enhance our understanding of the slurry infiltration mechanism and its practical application in TBM tunneling.

中文翻译：

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CFD-DEM 耦合法泥浆渗透的水力力学分析


隧道掌子面稳定性与粒状土中泥浆颗粒的运移行为和堵塞机制密切相关，目前尚不完全清楚。在本研究中，采用计算流体动力学-离散元耦合方法（CFD-DEM）来研究泥浆在颗粒尺度上的渗透行为。完整的 Johnson-Kendall-Roberts (JKR) 接触模型描述了颗粒间行为，该模型解释了即使颗粒在碰撞后微分离时仍存在的内聚力，该模型适用于粘土-粘土或粘土-砂颗粒，而 Hertz-Mindlin 模型则用于砂-砂粒子。通过模拟，确定了浆体颗粒堵塞的机理为物理、摩擦和内聚模式，浆体颗粒的迁移通常经历聚集-破坏-迁移-重组的过程。同时，还分析了压力、内聚力和颗粒形状对渗透的影响。结果表明，高压延长了渗透路径并提高了渗透速率。黏聚力的增加增强了浆液对砂柱的有效堵塞，球形度较小的颗粒更容易堵塞砂柱。这些发现可能会增强我们对泥浆渗透机制及其在TBM隧道掘进中的实际应用的理解。