This technical note uses bolt-reinforced jointed granite to investigate the relationship between the joint angle and the reinforcing effects of bolt. 3D-printed (3DP) bolts were manufactured with a real bolt as the model prototype, the dimensions and surface geometries were scaled up, and the mechanical properties were similar to those of the prototype bolt. The cylindrical granite specimens were prepared with each separated by a through-going inclined joint plane, the bolt and the granite were combined via bonding agent and nuts. The bearing capacity of the system, the loading status of the bolt, and the displacement/strain changing patterns on the surface of the granite were comprehensively investigated. The results indicated that granite tended to crack when the joint angle was small and that a higher joint angle weakened the bearing capacity of the system, even with the reinforcement of the bolt. For specimens with joint angles of 45° and 60°, a shearing tendency and strain concentration zones nearby the joint plane were clearly observed. This study provide a new methodology for studying the anti-shearing behaviour of bolt in fractured hard rock.

中文翻译：

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3D打印螺栓加固分节花岗岩破坏机理

本技术说明使用螺栓加固连接花岗岩来研究连接角度与螺栓加固效果之间的关系。3D打印（3DP）螺栓以真实螺栓为模型原型，按比例放大尺寸和表面几何形状，力学性能与原型螺栓相似。制备圆柱形花岗岩试件，每个试件由贯穿斜接面隔开，螺栓和花岗岩通过粘合剂和螺母结合。对系统的承载能力、螺栓的加载状态以及花岗岩表面的位移/应变变化模式进行了综合研究。结果表明，当接头角度较小时，花岗岩容易开裂，而较大的接头角度会削弱系统的承载能力，即使在螺栓加固的情况下。对于接头角度为 45°和 60°的试样，在接头平面附近可以清楚地观察到剪切趋势和应变集中区。该研究为研究断裂硬岩中锚杆的抗剪特性提供了一种新的方法。