To explore the initial orientation effect of ballast assembly on the reinforcement performance of the geogrid reinforced ballast, particles with random orientation and five prescribed rotational orientations were developed through particle flow code (PFC3D). The evolution laws of the pullout force and the principal directions of the normal contact force were systematically compared and analyzed. Furthermore, the mechanical responses such as pullout force, distribution of axial force, displacement vectors, force chain, and mesoscopic fabric were discussed. According to the displacement vectors of the ballast particles, the average thickness of the stable shear band is determined. The inherent relationships among the force chain, the rotational angle of the normal contact force, and the mesoscopic fabric parameters are revealed. The results show that the pullout force of specimens with the initial orientation of 45° increases monotonously during the pullout process, and the peak value of pullout force appears at the end of the test. The mesostructural analysis also confirms that the evolution of the principal direction of contact normal force is relatively steady during the pullout process, indicating that the specimen with 45° orientation possesses higher systematic stability and ductility. Moreover, the optimum interval from 56.68° to 57.30° is observed to remain in a self-adapting state for ballast assembly.

中文翻译：

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颗粒取向对土工格栅加筋道ast性能的影响

为了研究镇流器组件对土工格栅加筋道ast的初始性能的初始取向影响，通过粒子流代码（PFC3D）开发了具有随机取向和五个规定旋转取向的粒子。系统地比较和分析了拉拔力的演变规律和法向接触力的主要方向。此外，还讨论了机械响应，例如拔出力，轴向力分布，位移矢量，力链和介观织物。根据压载颗粒的位移矢量，确定稳定剪切带的平均厚度。揭示了力链，法向接触力的旋转角度和介观织物参数之间的固有关系。结果表明，在拉伸过程中，初始取向为45°的试样的拉拔力在拉拔过程中单调增加，并且在测试结束时出现拉拔力的峰值。细观结构分析还证实，在拉拔过程中，接触法向力主方向的演变相对稳定，表明具有45°取向的试样具有较高的系统稳定性和延展性。此外，观察到从56.68°到57.30°的最佳间隔可保持镇流器组件的自适应状态。细观结构分析还证实，在拉拔过程中，接触法向力主方向的演变相对稳定，表明具有45°取向的试样具有较高的系统稳定性和延展性。此外，观察到从56.68°到57.30°的最佳间隔可保持镇流器组件的自适应状态。细观结构分析还证实，在拉拔过程中，接触法向力主方向的演变相对稳定，表明具有45°取向的试样具有较高的系统稳定性和延展性。此外，观察到从56.68°到57.30°的最佳间隔可保持镇流器组件的自适应状态。