Evaluation of soil fabric using elastic waves during load-unload
Evaluation of soil fabric using elastic waves during load-unload
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DOI：
10.1016/j.jrmge.2022.12.004
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发表时间：
2022-12
影响因子：
7.3
通讯作者：
Yang Li;M. Otsubo;R. Kuwano
中科院分区：
文献类型：
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作者：
Yang Li;M. Otsubo;R. Kuwano
评估土壤结构的演变至关重要，因为它在复杂荷载条件下的土壤机械响应中发挥着重要作用。该贡献在实验室中使用三种颗粒材料进行了物理实验。研究了干燥和排水条件下加载-卸载循环期间压缩波速度和剪切波速度（V p 和 V s）的变化。进行补充离散元法 (DEM) 模拟，以了解使用球形颗粒的等效加载-卸载循环期间土壤结构的演变。即使应力状态在卸载后恢复到各向同性状态，V p 和V s 并不总是可逆的，这表明V p 和V s 不仅受应力状态的影响，而且还受织物变化的影响。 V p/V s 的变化取决于密度和应力；对于使用球形玻璃珠的实验结果和使用球形颗粒的模拟数据，观察到较高水平的应力比 (σ 1′/σ 3′) 阈值，以触发波速比 (V p/V s) 的显着变化。考虑到颗粒形状，对于更多有角颗粒比圆形颗粒而言，发现更高的 σ 1'/σ 3' 阈值。 DEM 结果表明，在干燥和排水条件下，在峰值前范围内加载-卸载期间，球形颗粒的 V p/V s 可以与织物比率 (Φ v e r/Φ h o r) 的演变线性相关。
It is essential to assess the evolution of soil fabric as it has an important role in the mechanical responses of soils during complex loading conditions. This contribution carries out the physical experiments using three granular materials in the laboratory. The variations of compression and shear wave velocities (V p and V s) are investigated during load-unload cycles under dry and drained conditions. Supplementary discrete element method (DEM) simulations are performed to understand the evolution of soil fabric during the equivalent load-unload cycles using spherical particles. V p and V s are not always reversible even though the stress state regains its isotropic condition after unload, indicating that V p and V s are governed by not only the stress state but also the fabric change. The variations of V p/V s are density-and stress-dependent; a higher level of stress ratio (σ 1′/σ 3′) threshold is observed for denser packings to trigger a significant change in wave velocity ratio (V p/V s) for experimental results using spherical glass beads and simulation data using spherical particles. Considering the particle shape, a higher σ 1′/σ 3′ threshold is found for more angular particles than rounded particles. The DEM result reveals that V p/V s of spherical particles can be correlated linearly with the evolution of fabric ratio (Φ v e r/Φ h o r) during load-unload in a pre-peak range under dry and drained conditions.