The study of rock fragmentation mechanism significantly contributes to the advancing speed of tunnel boring machines (TBMs). In this sense, numerous factors are shaping the rock fragmentation mechanism of their disc-cutters. Among them, rock structural parameters, such as joint inclination, orientation, spacing, etc., considerably impact cutting force as well as rock-cutting process. However, detailed relationships between rock-cutting parameters and rock mass ones have not been to date proven, and rock fragmentation mechanism still needs to be investigated in depth. In this paper, a three-dimensional (3D) discrete element model of rock-cutting using a disc-cutter was established via the high-performance MatDEM software. To simulate the fragmentation performance of the rock undergoing the impact load, an elastic–plastic contact model was firstly proposed based on the linear elastic contact model, verified by several mechanical experiments. Then, the influence of different joint parameters (e.g., joint inclination, orientation, spacing, etc.) on cutting force and rock fragmentation volume was examined. At the same time, the effect of joint parameters on specific energy (SE) was calculated to explore the joint influence on rock-cutting efficiency. The simulation results show that the elastic–plastic contact model can better simulate the plastic deformation characteristics of the brittle rock, and the improved model can imitate the generation of the rock fragment structure. As well, the influence of the joint orientation and spacing on the mean value of the cutting force and the rock fragmentation volume is obvious, and the propagation mode of the internal cracks in the rock varies with reference to the joint orientation. The existence of the joints also decreases the rock-cutting SE, and consequently the rock-cutting efficiency can reach the highest level when the joint spacing is equal to 50 mm and the joint orientation is about 30°. The opposite inclination of the joint correspondingly leads to the opposite change in the rock-cutting parameters, which can be eliminated through rotating cutting in practice. This study explores the influence of joint parameters on rock-cutting ones and reveals crack distribution mechanism in jointed rock mass.

对碎石机理的研究极大地促进了隧道掘进机（TBM）的发展。从这个意义上讲，许多因素正在影响其圆盘切割机的碎石机制。其中，岩石的结构参数，例如节理的倾角，方向，间距等，极大地影响了切削力以及岩石的切割过程。但是，目前尚未证实凿岩参数与岩体参数之间的详细关系，并且仍需深入研究碎石机理。在本文中，通过高性能的MatDEM软件建立了使用圆盘切割机切割岩石的三维（3D）离散元素模型。为了模拟岩石在冲击载荷下的破碎性能，首先在线性弹性接触模型的基础上提出了弹塑性接触模型，并通过多次机械实验对其进行了验证。然后，研究了不同节理参数（例如节理倾角，方向，间距等）对切削力和碎石体积的影响。同时，计算了节理参数对比能（SE）的影响，以探讨节理参数对切石效率的影响。仿真结果表明，弹塑性接触模型可以较好地模拟脆性岩石的塑性变形特征，改进后的模型可以模拟碎石结构的产生。同样，节理的方向和间距对切削力平均值和碎石体积的影响也很明显，岩石内部裂缝的传播方式根据节理方向而变化。接头的存在也降低了切石SE，因此当接头间距等于50 mm且接头方向约为30°时，切石效率可以达到最高水平。关节的相反倾斜相应地导致岩石切削参数发生相反的变化，这在实践中可以通过旋转切削消除。该研究探讨了节理参数对切岩参数的影响，并揭示了节理岩体中的裂缝分布机制。因此，当节距等于50 mm，节距约为30°时，凿岩效率可以达到最高水平。关节的相反倾斜相应地导致岩石切削参数发生相反的变化，这在实践中可以通过旋转切削消除。该研究探讨了节理参数对切岩参数的影响，并揭示了节理岩体中的裂缝分布机制。因此，当节距等于50 mm，节距约为30°时，凿岩效率可以达到最高水平。关节的相反倾斜相应地导致岩石切削参数发生相反的变化，这在实践中可以通过旋转切削消除。该研究探讨了节理参数对切岩参数的影响，并揭示了节理岩体中的裂缝分布机制。