In underground mining practice, the rock bolt support system is the major support pattern to control the deformation and stability of openings. A rock bolt is generally subjected to complex loads including tension, torsion, bending and shear, which result from the deformation of excavations and exposure to dynamic loads that are generated by rockbursts. An understanding of the response of rock bolt under complex conditions is of great importance for rock bolt support design and practice. New sophisticated equipment has been developed for this purpose. This work involved a comprehensive experimental study on the mechanical behavior of rock bolts under complex loads. The results show that rock bolt pre-tensioning by torque application to the nut can result in decreases in tensile strength and elongation because the rock bolt is subjected to a combination of tension and distortion. When a pre-tensioned rock bolt is subjected to a shear load, the maximum shear force can reach up to 80% of the tensile capacity of the rock bolt. Higher impact energy results in a longer period of dynamic loading and a larger irreversible plastic deformation on the rock bolt, in contrast to a rock bolt that is subjected to low impact energy. The capacity and especially the deformation capacity of a rock bolt may decrease significantly after successive containment of the deformation of the surrounding rock mass from rockbursts.

中文翻译：

---

复合静动载荷作用下锚杆力学行为的试验研究

在地下开采实践中，锚杆支护系统是控制开孔变形和稳定性的主要支护方式。锚杆通常承受复杂的载荷，包括拉伸、扭转、弯曲和剪切，这些载荷是由开挖变形和暴露于岩爆产生的动态载荷引起的。了解复杂条件下锚杆的响应对于锚杆支护设计和实践具有重要意义。为此目的开发了新的精密设备。这项工作涉及复杂载荷下岩石锚杆力学行为的综合试验研究。结果表明，通过对螺母施加扭矩来预张锚杆会导致抗拉强度和伸长率降低，因为锚杆同时受到拉伸和变形的影响。预张紧锚杆在承受剪切载荷时，最大剪切力可达锚杆抗拉能力的80%。与承受低冲击能量的岩栓相比，较高的冲击能量会导致岩栓承受更长的动态载荷周期和更大的不可逆塑性变形。岩爆对围岩变形的连续遏制后，锚杆的承载力，尤其是变形能力，可能会显着下降。最大剪切力可达锚杆抗拉能力的80%。与承受低冲击能量的岩栓相比，较高的冲击能量会导致岩栓承受更长的动态载荷周期和更大的不可逆塑性变形。岩爆对围岩变形的连续遏制后，锚杆的承载力，尤其是变形能力，可能会显着下降。最大剪切力可达锚杆抗拉能力的80%。与承受低冲击能量的岩栓相比，较高的冲击能量会导致岩栓承受更长的动态载荷周期和更大的不可逆塑性变形。岩爆对围岩变形的连续遏制后，锚杆的承载力，尤其是变形能力，可能会显着下降。