It is significant to conduct anchorage on the non-persistent jointed rock mass by bolts to inhabit the unstable fracture evolution of rock engineering. In this research, a series of experiments are done on 70 specimens to investigate the effect of anchorage method on strength and deformation behavior of a non-persistent jointed rock mass. First, based on the stress–strain curves of anchorage jointed specimens, the effect of anchorage method on the peak strength and elastic modulus of non-persistent jointed rock mass is investigated. The experimental results show that the peak strength and elastic modulus of jointed specimens changes with anchorage method for the same joint angle, while first decreases and then increases from 0° to 90° for the same anchorage method. Second, the effect of pretightening force on the strength and deformation behavior of anchorage jointed specimens is analyzed. The axial stress-axial strain curves of anchorage jointed specimens with various pretightening forces can be characterized into five types: (I) strain softening after the specimen drops to yield platform from peak strength; (II) strain hardening after the specimen drops to yield platform from peak strength; (III) strain hardening after the specimen yields; (IV) stepwise strain softening after the peak strength; (V) single stress drop after the peak strength. The peak strength and elastic modulus of jointed specimens for the same dip angle all increases nonlinearly with the pretightening force. And then, based on a series of surface failure mode of non-persistent jointed rock specimen, it can be seen that the initiation, propagation and coalescence of surface cracks depend on not only the joint angle, but also the magnitude of pretightening force. Twelve crack coalescence types are identified to analyze the surface crack mode of anchorage non-persistent jointed rock specimens. Finally, the effect of pretightening force on brittleness index of non-persistent jointed rock mass is made a discussion.

中文翻译：

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非持久节理岩体锚固力学行为及地表开裂特性试验研究

通过锚杆对非持久节理岩体进行锚固，对于解决岩石工程不稳定的断裂演化具有重要意义。本研究对70个试件进行了一系列试验，研究锚固方法对非持久节理岩体强度和变形行为的影响。首先，基于锚固节理试件的应力-应变曲线，研究了锚固方法对非持久节理岩体峰值强度和弹性模量的影响。试验结果表明，对于相同的接缝角度，接缝试件的峰值强度和弹性模量随锚固方法的变化而变化，而对于相同的锚固方法，从0°到90°先减小后增加。第二，分析了预紧力对锚固节点试件强度和变形行为的影响。不同预紧力锚固节点试件的轴向应力-轴向应变曲线可表征为五种类型：(I) 试件从峰值强度下降到屈服平台后的应变软化；(II) 试样从峰值强度下降到屈服平台后的应变硬化；(III) 试样屈服后的应变硬化；(IV) 峰值强度后逐步应变软化；(V) 峰值强度后的单一应力下降。相同倾角下连接试件的峰值强度和弹性模量均随预紧力呈非线性增加。然后，基于非持久节理岩石试件的一系列表面破坏模式，可以看出，起裂、表面裂纹的扩展和合并不仅取决于接头角度，还取决于预紧力的大小。确定了12种裂纹合并类型，分析了锚固非持久节理岩石试样的表面裂纹模式。最后讨论了预紧力对非持久节理岩体脆性指标的影响。