## 3 Results and Analyses
### Macroscale Behaviors
#### 3.1.2 Evolutionary Analysis of Shear Band Development  
S-RM specimens with gravel contents of 10%, 45%, and 80% were selected for the analysis of internal sectional views during deformation development. Additionally, the evolution of shear bands within the samples during the shear failure process was investigated, as depicted in Figure 7. A comparison of the observed deformations in S-RMs under varying axial strains revealed several noteworthy phenomena. In contrast to the findings in Figures 6 and 7, the total deformation of the specimens gradually became evident throughout the loading process; however, significant bulging deformation was not evident until peak stress levels were reached. Once this threshold was exceeded, the bulging rapidly intensified, particularly with notable particle movement at the mid-edge region of the specimens. As a discontinuous granular medium incorporating irregular stones, the S-RM further enhances the heterogeneity of the specimens. Observations from the particle rotation cloud diagram in Figure 7 reveal that the shear band does not exhibit a uniform structure but instead follows a winding pattern, extending outward in an asymmetrical \"X\" shape from the center of the sample. This phenomenon is more pronounced with increasing gravel content; specifically, as the gravel content increases, the shear band becomes less distinct. Notably, the rotational intensity of particles within the shear band is significantly higher than that of external particles. This behavior is attributed to localized granule rotation during axial loading, which leads to the formation of shear regions within the specimens. As a result of the relatively local density, particle translation becomes increasingly complex, and momentum transfer and dissipation primarily occur through particle rotation. As the axial load increases, the number of rotating particles gradually rises. At peak stress, these rotating particles penetrate local regions more effectively, forming a well-defined shear band. Continued loading until the specimen fails results in non-uniform expansion deformation at the center of the specimen, further promoting local particle rotation and altering the distribution, size, and shape of the shear band. Figure 6: _Cont._The rotation cloud diagrams of gravel clumps and sand particles in Figure 7a,c,e demonstrate that, under identical consolidation conditions, the rotational momentum of gravel clumps is significantly lower than that of sand particles. This observation provides further evidence for the heterogeneous characteristic of S-RMs. The discrepancy can be attributed to the higher moment of inertia exhibited by gravel clumps, which required more energy to achieve equivalent rotational momentum compared to sand particles. Despite their heterogeneity, S-RMs are considered a unified entity from a macroscopic perspective, with continuous energy transfer occurring between components. Therefore, when analyzing specimens consisting of identical granular systems holistically, it can be concluded that gravel clumps exhibit reduced rotational behavior compared to sand particles. Figure 6: Stress–strain curves of S-RM specimens with distinct gravel content and consolidation pressure. (**a**) \(\sigma_{3}=300\) kPa. (**b**) \(\sigma_{3}=500\) kPa. (**c**) \(\sigma_{3}=1000\) kPa. (**d**) Triaxial test outcomes of the S-RM in the work of [PERSON] [62]. (**e**) Triaxial test outcomes of the S-RM in the work of [PERSON] [63]. (**f**) Triaxial test results of the S-RM in the work of [PERSON] [64]. (**g**) Triaxial test results of the S-RM in the work of [PERSON] [65]. Figure 7: _Cont._  
Meanwhile, comparisons of specimens with varying gravel contents (Figure 7b,d,f) reveal that the overall rotational momentum of the particles increased as the gravel content decreased (GC = 10%). Conversely, specimens with high gravel content (GC = 80%) exhibit lower global rotational momentum due to increased local compactness differences between gravels.