Experimental investigation of crack propagation behavior and failure characteristics of cement infilled rock
Experimental investigation of crack propagation behavior and failure characteristics of cement infilled rock
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DOI：
10.1016/j.conbuildmat.2020.121735
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发表时间：
2021-01
影响因子：
7.4
通讯作者：
Shichuan Zhang;Yangyang Li;Liu Hui;Xianwen Ma
中科院分区：
文献类型：
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作者：
Shichuan Zhang;Yangyang Li;Liu Hui;Xianwen Ma
深入了解充填节理岩体的破坏特征是地下工程研究的关键问题，对相关工程的设计、施工和维护至关重要。本文通过单轴压缩试验，研究了节理布置（不同岩桥角度）对含一组相同尺寸和角度的预先存在的充填缺陷的红砂岩的强度和裂纹扩展的影响，并通过声发射和应变监测观察了裂缝的破裂过程。当岩桥与加载应力夹角小于24°时，岩体破坏形式为张拉破坏，裂隙贯通破坏的岩桥局部发生剪切破坏，整体承载能力下降。应变和声发射信号的拐点明显是由裂纹萌生和扩展引起的，剪切裂纹萌生所消耗的能量大于拉伸裂纹。利用断裂力学数值程序FRACOD进一步研究了不同加载应力条件下的裂纹扩展规律和破坏机制。3个2D相似模型的模拟结果表明：开放裂缝百分比减小，但滑移增加；此外，随着围应力的增加，裂缝的总长度也大大减小。这些结果对于理解深部地下矿山开挖中岩石工程的裂缝机理具有重要意义和价值。
A detailed understanding of the failure characteristics of infilled jointed rock is a key concern in underground engineering and is critical to the design, construction and maintenance of relevant projects. In this paper, uniaxial compression tests were performed to investigate the effect of the joint arrangement (different rock bridge angles) on the strength and crack propagation of red sandstone containing a set of preexisting infilled flaws of the same sizes and angles, while the crack fracturing process was observed by AE and strain monitoring. When the angle between the rock bridge and loading stress was less than 24°, the rock mass failure form was tensile failure with some localized shear failure occurring in the rock bridge damaged by crack penetration, leading to an overall decrease in the carrying capacity. The turning points of the strain and AE signal were clearly observed to be caused by the initiation and propagation of cracks, and the energy consumed by the initiation of shear cracks was greater than that of tensile cracks. The study was further conducted using the fracture mechanics numerical code FRACOD to investigate the crack propagation law and failure mechanism under different loading stress conditions. Simulation results from three 2D similar models showed that the percentage of open fractures decreased, but slipping increased; in addition, the total length of the fractures was greatly reduced with increasing confining stress. These results are important and valuable for understanding the crack mechanism of rock engineering in deep underground mining excavations.