Abstract The grain-based model (GBM) in two-dimensional Particle Flow Code (PFC2D) is widely employed to investigate the mechanical response characteristics of crystalline rocks under external load considering the realistic petrographic texture. However, due to the poor self-locking effect of the Parallel-Bond (PB) inside the minerals and unreasonable parametric assignment for the Smooth-Joint (SJ) at the mineral boundaries, the original GBM cannot reproduce the exact microcracking process of brittle rocks. To solve the problem, the novel grain-based model (nGBM) composed of the Flat-Joint (FJ) and the SJ was proposed in our previous research, which not only enhances the rotational resistance of particles, but also improves the simulation of the mineral boundaries. In this study, the nGBM was carefully established and calibrated based on the properties of Alxa porphyritic granite. A series of simulation tests of uniaxial compression, triaxial compression and direct tension under different mineral boundary parametric conditions were carried out to observe the deformation, microcracking and failure behaviors of the nGBM. Quantitative analyses of the mineral boundary properties and the mechanical behaviors of the numerical specimen revealed the extremely complicated relationships between them, which can help explain the micromechanical damage process of crystalline rocks and provide valuable reference for the model calibration.

中文翻译：

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基于新型粒基模型的矿物边界强度影响结晶岩破裂的参数研究

摘要 二维粒子流编码（PFC2D）中的基于颗粒的模型（GBM）被广泛用于研究考虑现实岩相结构的外载荷作用下结晶岩的力学响应特性。然而，由于矿物内部平行键（PB）的自锁效果较差，矿物边界处的光滑接头（SJ）参数分配不合理，原始GBM无法准确再现脆性岩石的微裂纹过程. 为了解决这个问题，我们在之前的研究中提出了由Flat-Joint（FJ）和SJ组成的新型基于颗粒的模型（nGBM），它不仅增强了粒子的旋转阻力，而且提高了对粒子的模拟。矿物边界。在这项研究中，nGBM 是根据阿拉善斑状花岗岩的特性精心建立和校准的。进行了不同矿物边界参数条件下的单轴压缩、三轴压缩和直接拉伸的一系列模拟试验，观察了nGBM的变形、微裂纹和破坏行为。对矿物边界性质和数值试样力学行为的定量分析揭示了它们之间极其复杂的关系，有助于解释结晶岩的微观力学损伤过程，为模型标定提供有价值的参考。进行了不同矿物边界参数条件下的三轴压缩和直接拉伸，以观察 nGBM 的变形、微裂纹和破坏行为。对矿物边界性质和数值试样力学行为的定量分析揭示了它们之间极其复杂的关系，有助于解释结晶岩的微观力学损伤过程，为模型标定提供有价值的参考。进行了不同矿物边界参数条件下的三轴压缩和直接拉伸，以观察 nGBM 的变形、微裂纹和破坏行为。矿物边界性质和数值试样力学行为的定量分析揭示了它们之间极其复杂的关系，有助于解释结晶岩的微观力学损伤过程，为模型标定提供有价值的参考。