Abstract Mechanical properties of crystalline rock are greatly affected by its micro-structures which are characterized as highly-interlocked polygon grains and presence of micro-defects. Due to insufficient consideration of micro-structures in crystalline rock, previous simulations using discrete element method (DEM) cannot realistically reproduce the mechanical properties of crystalline rock including crack closure behaviour and high ratio of uniaxial compressive strength (UCS) against tensile strength (TS). The irregular shape of minerals in crystalline rock is modelled by discrete element method (DEM) using grain-based model (GBM). Presence of initial cracks is incorporated into GBM by introducing two notional contact surfaces to model gradual closure behaviour under compressive loading, and to obtain a higher UCS/TS ratio. The stress-strain response and crack evolution including crack closure, crack initiation, crack coalescence as well as development of macroscopic shear failure can be realistically reproduced with the proposed model. A calibration procedure is proposed to match properties of Remiremont granite under room temperature. The influence of initial cracks on the rock is then comprehensively studied. The simulation results show a good agreement with the experimental outputs under various treatment temperatures. By modelling the polygon grain and pre-existing cracks, the simulated UCS/TS ratio can be more realistic and increased up to a value of 49.

中文翻译：

---

考虑预先存在的裂缝的基于晶粒的模型，用于模拟结晶岩的力学特性

摘要 结晶岩的力学性能受其显微结构的影响很大，其特征是高度互锁的多边形晶粒和微缺陷的存在。由于对结晶岩的微观结构考虑不足，以前使用离散元法 (DEM) 进行的模拟无法真实再现结晶岩的力学性能，包括裂缝闭合行为和单轴抗压强度 (UCS) 与抗拉强度 (TS) 的高比率. 使用基于颗粒的模型 (GBM) 通过离散元方法 (DEM) 对结晶岩中矿物的不规则形状进行建模。通过引入两个概念接触面来模拟压缩载荷下的逐渐闭合行为，并获得更高的 UCS/TS 比，将初始裂纹的存在纳入 GBM。应力应变响应和裂纹演化，包括裂纹闭合、裂纹萌生、裂纹合并以及宏观剪切破坏的发展，可以用所提出的模型真实地再现。提出了一种校准程序，以匹配室温下 Remiremont 花岗岩的特性。然后全面研究初始裂缝对岩石的影响。模拟结果表明在各种处理温度下与实验输出有很好的一致性。通过对多边形纹理和预先存在的裂纹进行建模，模拟的 UCS/TS 比值可以更加真实，并增加到 49。提出了一种校准程序，以匹配室温下 Remiremont 花岗岩的特性。然后全面研究初始裂缝对岩石的影响。模拟结果表明在各种处理温度下与实验输出有很好的一致性。通过对多边形纹理和预先存在的裂纹进行建模，模拟的 UCS/TS 比值可以更加真实，并增加到 49。提出了一种校准程序，以匹配室温下 Remiremont 花岗岩的特性。然后全面研究初始裂缝对岩石的影响。模拟结果表明在各种处理温度下与实验输出有很好的一致性。通过对多边形纹理和预先存在的裂纹进行建模，模拟的 UCS/TS 比值可以更加真实，并增加到 49。