同组软硬煤煤样声发射及分形特征研究

STUDY OF ACOUSTIC EMISSION AND FRACTAL CHARACTERISTICS OF SOFT AND HARD COAL SAMPLES WITH SAME GROUP

为了研究在单轴压缩下同组软硬煤试样的声发射及分形特征,以平煤集团已组软硬煤为研究对象,利用RMT–150C型岩石力学伺服试验系统和CDAE–1型声发射仪,在单轴压缩下对平煤集团的己组软硬煤煤样进行声发射试验,然后运用分形理论分析声发射计数序列。研究结果表明:在单轴压缩破坏过程中,软硬煤试样的声发射累计计数都会出现突增现象,软煤的平均增长率为855.4,硬煤的平均增长率为914.32。相空间维数对关联维数有一定的影响,但是随着相空间维数的增加影响会越来越小。软硬煤声发射计数序列的分形维数在加载初期都比较小,在峰值应力附近会达到最大值,之后会出现突降现象,这可以作为预测煤体失稳破坏的前兆。

In order to study of acoustic emission and fractal characteristics of soft and hard coal with same group under uniaxial compression,focusing on group Yi soft and hard coal in Pingmei Group,an experimental study is carried out to investigate the acoustic emission characteristics of soft and hard coal with the same group in Pingmei group by using RMT–150C rock mechanics test system and CDAE–1 acoustic emission instrument,and analyze the fractal characteristics of the acoustic emission count sequence. The results show that phenomenon of the acoustic emission cumulative count surge appears the soft and hard coal samples in failure process under compression uniaxial. The average growth rate is 855.4 of soft coal and the average growth rate is 914.32 of hard coal. Phase space dimension has a certain influence on the correlation dimension,but the effect will be more and more smaller with increasing of the phase space dimension. The fractal dimension is relatively small of acoustic emission cumulative count sequence of the soft and hard coal at the initial loading stage, and at the near peak stress it will reach the maximum value, and then it will appear dump phenomenon, at last it can be used as a forewarning of the instability failure of coal body.