The structural and anisotropic features of meso-structures consisting of a series of contacted particles hold the key to understanding the local shear failure and multi-scale mechanics of granular materials. However, the link between these meso-structures and their material deformation and failure characteristics have not yet been fully elucidated. By the means of Discrete Element Method (DEM), this study aimed to fill this gap by offering insights into the roles that meso-structures play in a range of mechanical behaviors, including the shear strength, shear banding and shear-induced anisotropy of a quasi-statically deforming granular system. The deformation process of various kinds of meso-structures was characterized by the evolution of two indices, a stability index and a degradation index. The first index was derived from the stiffness matrix of a particle cluster representing a meso-structure, and depicts its degree of vulnerability to intra-cluster deformation. The second index was derived from the survival probabilities of all the particles constituting a cluster against breakage, and depicts its degree of vulnerability to degradation. Furthermore, a set of anisotropic items were introduced to characterize the role of different kinds of meso-structures in the multi-scale mechanism of the shear strength behavior of the granular system.

由一系列接触颗粒组成的细观结构的结构和各向异性特征是理解颗粒材料局部剪切破坏和多尺度力学的关键。然而，这些细观结构与其材料变形和破坏特性之间的联系尚未完全阐明。通过离散元方法 (DEM)，本研究旨在通过深入了解细观结构在一系列力学行为中的作用，包括剪切强度、剪切带和剪切诱导的各向异性，来填补这一空白。准静态变形颗粒系统。各种细观结构的变形过程具有两个指标的演化特征，一个是稳定性指标，一个是退化指标。第一个指标来自代表细观结构的粒子簇的刚度矩阵，并描述了其对簇内变形的脆弱程度。第二个指数是从构成一个簇的所有粒子的存活概率推导出来的，并描述了它对降解的脆弱程度。此外，还引入了一组各向异性项来表征不同类型的细观结构在颗粒系统抗剪强度行为的多尺度机制中的作用。