The deformation process and failure mechanism of rock mass with increased density of initial joints subjected to confined stress state are investigated in this study using discrete element method (DEM). A numerical model of standard size granite samples is developed and validated using experimental data for both intact and jointed rocks. The micro-parameters of the rock material are first determined, and the effects of the rock discontinuity on strength, deformability, stress–strain relationship, and failure modes are then investigated at the macro-scale level. Analyses are also performed to examine the tensile and shear crack distributions, fragmentation characteristics, particle kinematics, and energy dissipation to advance the current understanding of the deformation processes and failure mechanisms of jointed rock masses. The microscopic evolutions in the fabric and force anisotropy during loading and distributions of contact forces provide insights into the influence of increasing initial jointing on the macroscopic deformational behavior of the rock. The results show how the deceleration in the growth of fabric and contact force anisotropies develops and confirms that the increase in initial jointing and the associated changes in microstructure can restrain the development of anisotropy, thereby reducing significantly the strength of the rock samples.

本研究采用离散元法研究了初始节理密度增加的围岩在有限应力状态下的变形过程和破坏机理。利用完整和节理岩石的实验数据，开发并验证了标准尺寸花岗岩样品的数值模型。首先确定岩石材料的微观参数，然后在宏观尺度上研究岩石不连续性对强度，变形性，应力-应变关系以及破坏模式的影响。还进行分析以检查拉伸和剪切裂缝的分布，破碎特征，颗粒运动学和能量耗散，以增进对节理岩体变形过程和破坏机理的当前理解。接触力的加载和分布过程中织物的微观演变和力各向异性为深入了解初始节理对岩石宏观变形行为的影响提供了见识。结果表明，织物生长的减速度和接触力各向异性如何发展，并证实了初始接缝的增加和相关的微观结构变化可以抑制各向异性的发展，从而显着降低岩石样品的强度。