Experimental and numerical investigation of crack propagation in bolting systems strengthened with resin-encapsulated rock bolts
Experimental and numerical investigation of crack propagation in bolting systems strengthened with resin-encapsulated rock bolts
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DOI：
10.1016/j.engfailanal.2021.105259
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发表时间：
2021-02-10
影响因子：
4
通讯作者：
Li, Huaizhen
中科院分区：
文献类型：
--
作者：
Chong, Zhaohui;Yue, Tenglong;Li, Huaizhen
岩石加固设计需要清楚地了解锚杆系统中裂纹的产生和扩展。为了更好地了解其机理，我们对树脂封装岩石锚杆进行了实验室拉拔测试。使用离散元方法建立了 1:1 比例的数值模型。基于无侧限压缩试验和环剪试验对模型的微观参数进行了标定。该模型使我们能够可视化用树脂封装岩石锚杆加固的锚杆系统的渐进失效，并阐明锚固长度在控制裂纹扩展中的作用。比较表明物理结果和数值结果是一致的。结果表明，增加锚固长度可提高锚杆系统的粘结性和强度，并抑制锚杆与水泥砂浆的完全脱粘。同时，也有利于剪切裂纹向拉伸裂纹的转化。然而，树脂的剪切裂纹是螺栓系统中的主要影响。此外，结果揭示了边界围压、树脂厚度和水泥砂浆强度等因素如何影响裂纹的萌生和扩展。
Rock reinforcement design necessitates a clear understanding of the initiation and propagation of cracks in the bolting system. To better understand the mechanism, we performed laboratory pullout tests on resin-encapsulated rock bolts. Numerical models on a 1:1 scale were built using the discrete element method. The microscopic parameters of the model were calibrated based on unconfined compression tests and ring shear tests. The model allows us to visualize the progressive failure of a bolting system strengthened with resin-encapsulated rock bolts and elucidates the role of the anchorage length in controlling crack propagation. Comparisons indicate that the physical and numerical results are consistent. The results show that increasing the anchorage length improves the bondability and strength of the bolting system and restrains the complete debonding of the rock bolt from the cement mortar. At the same time, it also facilitates the conversion of shear cracks to tensile cracks. However, the shear crack of the resin is the dominant effect in the bolting system. In addition, the results reveal how factors such as boundary confining pressure, resin thickness, and cement-mortar strength affect crack initiation and propagation.