During the rockburst experiments on the granite specimens under different intermediate princi-pal stresses,the acoustic emission(AE)system is adopted to obtain the AE signal.The rockburst process,vertical stress when rockburst and the AE ring-down counts are investigated.And the multifrac-tal characteristics of the AE ring-down counts in the time domain during the process of rapid increasing vertical stress until the end of rockburst is analyzed with multifractal theory.The results show that the higher the intermediate principal stress,the more intense the rockburst.When the vertical stress level at rockburst tends to stabilize,the accumulated AE ring-down counts during the rapid increasing vertical stress tends to increase.With the increase of the vertical stress,the multifractal spectrum of AE ring-down counts shows a trend of wide to narrow to wide variation.The width of the multifractal spectrum mainly present a decreasing-increasing trend where a turning point in the smooth curve of the spectrum width can be identified for rockburst warning.It is found that the higher the intermediate principal stress,the longer the rockburst warning time,and the decrease in rockburst suddenness.As approaching to rockburst,the nonlinearity of the generalized fractal spectrum gradually weakens,but becomes obvious when rockburst.The distribution uniformity of the AE ring-down counts in the time domain tends to in-crease with the increase of the intermediate principal stress.The research indicates that under the high principal stress and the rapid increasing vertical stress,the continuous cracking behavior during the rock-burst experiment process will be enhanced.
关键词
岩爆试验/中主应力/声发射/多重分形特征/岩爆预警
Key words
rockburst experiments/intermediate principal stress/acoustic emission/multifractal/rock-burst warning
维普
万方数据