Rockbolt is a common support method in underground tunnel engineering, used to enhance the strength of rock mass and improve the stability of surrounding rock. In this paper, the three-dimensional (3D) FDEM method is employed to study the influence of rockbolts on the deformation and crack evolution of surrounding rock in tunnel engineering. Firstly, the CUDA-based GPU parallel 3D FDEM algorithm is briefly described, and its calculation process is summarized. At the same time, the contact search grid partitioning algorithm is optimized to address the problem of program crashes caused by grid memory overflow. Subsequently, a new rockbolt characterization method suitable for 3D FDEM algorithm is proposed, and the calculation process and constitutive equation of the new rockbolt algorithm are described in detail. The accuracy and feasibility of the new rockbolt algorithm are successfully verified by the pull-out test model and the three-point test model. Next, the numerical simulation of TBM tunnel project is carried out to study the deformation behavior and crack evolution path of surrounding rock after tunnel excavation. The results show that the vertical displacement of surrounding rock at the top of rockbolt tunnel model is greatly reduced, the crack development process is slowed down and the number of cracks is reduced. Finally, the influence of rockbolt row spacing and length on the deformation and crack propagation of surrounding rock is discussed. It is found that as the spacing decreases or the rockbolt length increases, the number of cracks in the surrounding rock gradually decreases, and the vertical displacement at the top of the surrounding rock gradually reduces. This study is helpful to understand the influence of rockbolts on the stability of surrounding rock, especially in tunnel engineering, it is of great significance for adjusting the rockbolt scheme under adverse geological conditions.

中文翻译：

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一种新型的三维锚杆模型及其在隧道开挖中的应用


锚杆是地下隧道工程中常用的支护方法，用于增强岩体的强度，提高围岩的稳定性。本文采用三维 （3D） FDEM 方法研究了隧道工程中锚杆对围岩变形和裂纹演化的影响。首先，简要介绍了基于 CUDA 的 GPU 并行 3D FDEM 算法，并总结了其计算过程;同时，优化了 contact search grid 分区算法，解决了 grid 内存溢出导致的程序崩溃问题。随后，提出了一种适用于三维 FDEM 算法的新型 Rockbolt 表征方法，并详细描述了新 Rockbolt 算法的计算过程和本构方程。通过拉拔试验模型和三点试验模型成功验证了新型锚杆算法的准确性和可行性。接下来，对TBM隧道工程进行数值模拟，研究隧道开挖后围岩的变形行为和裂缝演化路径。结果表明：锚杆隧道模型顶部围岩竖向位移大幅减小，裂缝发展过程加快，裂缝数量减少;最后，讨论了锚杆行距和长度对围岩变形和裂纹扩展的影响。研究发现，随着间距减小或锚杆长度增加，围岩中的裂缝数量逐渐减少，围岩顶部垂向位移逐渐减小。 本研究有助于理解锚杆对围岩稳定性的影响，特别是在隧道工程中，对恶劣地质条件下锚杆方案的调整具有重要意义。