Abstract Rock masses in underground excavations are exposed to cyclic loading due to several factors, such as blasting and mechanical excavation, etc. However, the understanding for the effect of cyclic loadings on rock damage remains not completely clear. To this end, we have investigated the crack development and mechanical behavior of marble under three different cyclic loadings. The results showed that the crack closure threshold can be improved by cyclic loadings. The crack initiation threshold, crack damage threshold, cohesion and elastic modulus initially increase with the cycles, followed by a decrease as the rock heads toward failure. The cohesion is proportional to the elastic modulus before the latter reaches its maximum value. Further, additional cyclic loadings exhibited evident compaction effect on the rock. Meanwhile, the cyclic loadings caused simultaneous strengthening and damage effect of rocks. The proposed strengthening principle is implemented in the well-established rock failure process analysis (RFPA) code. The model is then validated by comparing the simulation and experiment results. Based on the experiment results, the cohesion weakening and frictional strengthening (CWFS) model is amended as the cohesion variation and frictional strengthening (CVFS) model.

中文翻译：

---

单轴循环荷载压缩下大理岩裂纹扩展及力学行为的试验与数值研究

摘要 由于爆破和机械开挖等多种因素，地下开挖中的岩体承受循环荷载。然而，对循环荷载对岩石破坏的影响的认识尚不完全清楚。为此，我们研究了大理石在三种不同循环载荷下的裂纹发展和力学行为。结果表明，循环加载可以提高裂纹闭合阈值。裂纹萌生阈值、裂纹损伤阈值、内聚力和弹性模量最初随着循环而增加，然后随着岩石走向破坏而减少。在弹性模量达到最大值之前，内聚力与弹性模量成正比。此外，额外的循环载荷对岩石表现出明显的压实作用。同时，循环荷载同时引起岩石的强化和破坏作用。建议的加固原理在完善的岩石破坏过程分析 (RFPA) 规范中实施。然后通过比较模拟和实验结果来验证模型。根据实验结果，将凝聚力减弱与摩擦强化（CWFS）模型修正为凝聚力变化与摩擦强化（CVFS）模型。