Abstract Accurate design of geotechnical structures requires precise estimation of the shear wave velocity (Vs) and the small-strain shear modulus. However, the interpretation of Vs data measured in deformed/sheared soil has not been extensively considered. This study used a triaxial apparatus equipped with planar piezoelectric transducers to monitor the evolution of Vs during triaxial compression of cohesionless soils. Recognizing that the grain shape and surface characteristics affect the overall mechanical response of granular materials, various natural sands and glass bead samples were considered. Discrete element method (DEM) simulations using spherical particles were carried out to compute particle-scale responses that cannot be measured in the laboratory. The experimental results revealed that the Vs values for samples with different initial densities tend to approach one another and have similar values (merge) at large axial strains. This merging occurs at a lower strain level for spherical particles in comparison with non-spherical particles. The linear Vs-void ratio relationship, which is often developed and used for homogeneous and isotropic stress states, is no longer applicable during shearing. It is the mean coordination number that dictates the evolution of Vs during triaxial compression. Furthermore, the axial strain at which the peak Vs is achieved is found to be comparable to the axial strain at which specimen dilation takes place.

中文翻译：

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三轴压缩过程中横波速度的演变

摘要 岩土结构的精确设计需要精确估计剪切波速度 (Vs) 和小应变剪切模量。然而，在变形/剪切土中测量的 Vs 数据的解释尚未得到广泛考虑。本研究使用配备平面压电换能器的三轴装置来监测无粘性土壤三轴压缩过程中 Vs 的演变。认识到颗粒形状和表面特征会影响颗粒材料的整体机械响应，考虑了各种天然砂和玻璃珠样品。使用球形粒子进行离散元方法 (DEM) 模拟，以计算无法在实验室中测量的粒子尺度响应。实验结果表明，具有不同初始密度的样品的 Vs 值趋向于彼此接近，并且在大轴向应变下具有相似的值（合并）。与非球形颗粒相比，球形颗粒的这种合并发生在较低的应变水平。线性 Vs-空隙比关系通常在均匀和各向同性应力状态下开发和使用，在剪切过程中不再适用。平均配位数决定了三轴压缩过程中 Vs 的演变。此外，发现达到峰值 Vs 时的轴向应变与发生试样膨胀时的轴向应变相当。与非球形颗粒相比，球形颗粒的这种合并发生在较低的应变水平。线性 Vs-空隙比关系通常在均匀和各向同性应力状态下开发和使用，在剪切过程中不再适用。平均配位数决定了三轴压缩过程中 Vs 的演变。此外，发现达到峰值 Vs 时的轴向应变与发生试样膨胀时的轴向应变相当。与非球形颗粒相比，球形颗粒的这种合并发生在较低的应变水平。线性 Vs-空隙比关系通常在均匀和各向同性应力状态下开发和使用，在剪切过程中不再适用。平均配位数决定了三轴压缩过程中 Vs 的演变。此外，发现达到峰值 Vs 时的轴向应变与发生试样膨胀时的轴向应变相当。