Multidirectional shearing tests on soils in the laboratory suffer from drawbacks such as non-uniformity of stress and unknown horizontal stress of the specimen. As a promising numerical technique, the discrete element method (DEM) enables investigation of the responses of virtual granular samples under general loading conditions and provides ideal numerical results to overcome the aforementioned limitations. In this study, three different drained cyclic tests, including conventional rotational shear, bidirectional circular rotational shear, and bidirectional elliptical rotational shear, were conducted on both isotropic and transversely isotropic samples under various stress ratios and density conditions. In all these tests, the magnitudes of the three principal stresses were kept constant during the entire loading process. Principal stress rotation occurred in one deviatoric stress plane in a conventional rotational shearing test but spatially (not necessarily in one plane) in the other two bidirectional shearing tests. The normalized deviatoric strain increment was decomposed into (1) coaxial and proportional, (2) coaxial and orthogonal, and (3) totally non-coaxial parts in reference to the deviatoric stress tensor. Their evolutions are presented and discussed in detail herein. The internal structure quantified by the contact-normal-based fabric tensor was tracked, and its correlation with the imposed stress path is illustrated.

实验室土壤多向剪切试验存在应力不均匀、试样水平应力未知等缺点。作为一种很有前途的数值技术，离散元法 (DEM) 能够研究虚拟颗粒样品在一般载荷条件下的响应，并提供理想的数值结果来克服上述限制。在这项研究中，在各种应力​​比和密度条件下对各向同性和横向各向同性样品进行了三种不同的排水循环试验，包括常规旋转剪切、双向圆形旋转剪切和双向椭圆旋转剪切。在所有这些测试中，三个主应力的大小在整个加载过程中保持恒定。在传统的旋转剪切试验中，主应力旋转发生在一个偏应力平面上，但在其他两个双向剪切试验中发生在空间上（不一定在一个平面上）。参考偏应力张量，归一化偏应变增量被分解为（1）同轴和成比例，（2）同轴和正交，以及（3）完全非同轴部分。此处详细介绍和讨论了它们的演变。跟踪由基于接触法线的织物张量量化的内部结构，并说明其与施加的应力路径的相关性。参考偏应力张量，归一化偏应变增量被分解为（1）同轴和成比例，（2）同轴和正交，以及（3）完全非同轴部分。此处详细介绍和讨论了它们的演变。跟踪由基于接触法线的织物张量量化的内部结构，并说明其与施加的应力路径的相关性。参考偏应力张量，归一化偏应变增量被分解为（1）同轴和成比例，（2）同轴和正交，以及（3）完全非同轴部分。此处详细介绍和讨论了它们的演变。跟踪由基于接触法线的织物张量量化的内部结构，并说明其与施加的应力路径的相关性。