Microscopic Mechanism of Coarse-Grained Soil Under Triaxial Test Based on PFC-FLAC Coupling Method
Microscopic Mechanism of Coarse-Grained Soil Under Triaxial Test Based on PFC-FLAC Coupling Method
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DOI：
10.1007/s11204-023-09897-w
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发表时间：
2023-09
影响因子：
0.8
通讯作者：
X. Zhang;K. Luo;T. Wang;M. Jiang;J. Feng;G. Mei
中科院分区：
文献类型：
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作者：
X. Zhang;K. Luo;T. Wang;M. Jiang;J. Feng;G. Mei
采用颗粒流程序(PFC) -连续体快速拉格朗日分析（FLAC）耦合方法研究了粗粒土在三轴载荷作用下的微观机制。根据材料的级配，建立了考虑三轴载荷下柔性膜变形影响的数值模型。通过与室内三轴试验结果的对比，验证了数值模型的有效性和可靠性。在此基础上，从介观角度分析了颗粒的运动规律和颗粒间力链的变化规律。对加载过程中的配位数、变形细观机制、破坏（裂纹数）和能量变化进行了研究。从细观角度解释了粗粒土的变形机理：粗粒土主要依靠由颗粒组成的骨架来承受荷载。土体的变形是由颗粒的运动、空隙的填充以及颗粒骨架结构的变化引起的。配位数随轴向应变的增大而增大。模型中的裂纹以剪切裂纹为主，与室内三轴试验结果一致。粗粒土的加载过程与能量变化密切相关。
This study investigated the microscopic mechanism of coarse-grained soil under triaxial loading using the Particle Flow Code (PFC) – Fast Lagrangian Analysis of Continua (FLAC) coupling method. A numerical model considering the influence of flexible membrane deformation under triaxial loading was established according to the gradation of the material. Then, the validity and reliability of the numerical model were verified by comparison with the laboratory triaxial test results. On this basis, the motion law of particles and the change law of the force chain between the particles were analyzed from the mesoscopic perspective. The coordination number, meso-mechanism of deformation, failure (number of cracks), and energy variation during the loading process were investigated. The deformation mechanism of coarse-grained soil is explained from the mesoscopic perspective: coarse-grained soil mainly depends on a skeleton consisting of particles to bear loads. The deformation of soil is caused by the movement of particles, filling of voids, and change of the particle skeleton structure. The coordination number develops as the axial strain increases. The cracks in the model were mainly shear cracks, which is consistent with the results of the laboratory triaxial test. Finally, the loading process of the coarse-grained soil was closely related to the variation of energy.