Abstract
The stability analysis of rock is an important basis to ensure the safe exploitation of underground resources and the reliable operation of space engineering. Uniaxial compression and acoustic emission (AE) tests were carried out on two common rock samples with strong rock burst tendency. The relationship between mechanical characteristics, AE characteristics, and rock burst tendency in the failure process of rock with different body types and the evolution of fractal characteristics of AE parameters were discussed. Based on the cusp mutation theory, the catastrophe model of AE characteristic parameters was established to quantify the instability mechanism of rock mass. The results show that the AE mutation rate (AEMR) of the cubic specimens increase from a low level to a high level gradually in the stable fracture stage, while that of the cylindrical specimens increase sharply to the maximum when the specimens are near failure. The AE cumulative energy curves of cubic specimens show a “step” rise, while that of cylindrical specimens show a “gradual” rise, and the rock burst process of cubic specimens is faster. The fractal dimension evolution mode of AE characteristic parameters of cubic specimens during uniaxial compression text is decline-rise-decline, while that of cylindrical specimen is decline-rise-decline-steeply rise. According to the periodic change of AE cumulative energy curve, combined with the rock failure cusp mutation model, the occurrence of rock burst can be well predicted, providing certain theoretical guidance for the stability analysis of underground engineering rock mass.
Highlights
Academic Editor: Dong Zhao e stability analysis of rock is an important basis to ensure the safe exploitation of underground resources and the reliable operation of space engineering
Based on the cusp mutation theory, the catastrophe model of acoustic emission (AE) characteristic parameters was established to quantify the instability mechanism of rock mass. e results show that the AE mutation rate (AEMR) of the cubic specimens increase from a low level to a high level gradually in the stable fracture stage, while that of the cylindrical specimens increase sharply to the maximum when the specimens are near failure. e AE cumulative energy curves of cubic specimens show a “step” rise, while that of cylindrical specimens show a “gradual” rise, and the rock burst process of cubic specimens is faster. e fractal dimension evolution mode of AE characteristic parameters of cubic specimens during uniaxial compression text is decline-rise-decline, while that of cylindrical specimen is decline-rise-decline-steeply rise
Zhang et al [7] took AE energy, ringing count, rising time, and main frequency as Advances in Civil Engineering characteristic parameters to perform clustering analysis on AE signals generated in the process of roadway rock burst and obtained three types of rock fracture corresponding to the AE signals
Summary
According to the stress-strain curves and mechanical characteristic parameters of cubic and cylindrical specimens, it can be seen that the strength of the cube specimens is larger than that of the cylindrical specimens due to its larger effective stiffness and the stronger resistance to deformation. It can be seen that both the stress-strain curves of cubic and cylindrical specimens have initial compaction stage, linear elastic deformation, stable fracture stage, and failure and instability stage. The inhomogeneity of the internal microstructure in granite is relatively larger, and the ends are quickly compacted when the specimen is compressed, resulting in fracture and expansion failure. As the load continues to increase, a multifragmentation burst failure occurs eventually and the cracks are more dispersed, which is consistent with the result that granite has strong rock burst tendency [27]
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