基于小波去噪的充填体声发射序列分形特征研究

Study on Fractal Characteristics of Acoustic Emission Sequence of Filling Body Based on Wavelet De-noising

为了获取充填体在外荷载作用下声发射序列的分形特征,对灰砂比为1∶6的充填体试样进行单轴压缩声发射试验,并利用小波分析去除声发射信号中的噪声信息,在此基础上研究试样破坏各过程的声发射活动情况及其分形特征。研究表明未去噪的声发射特征参数的峰值会提前出现;随着相空间维数的增大,分形维数呈现出一种先增大后稳定的趋势;声发射序列的分形维数在应力接近峰值时骤减,此时试样出现主破裂。分形维数在试样失稳破坏前期呈现出波动到稳定的变化趋势,该特征为分形理论应用在充填采矿的安全监测提供依据。

In order to obtain the fractal characteristics of the acoustic emission sequence of filling body under external loads, the uniaxial compression acoustic emission test on the filling body with cement-sand ratio of 1 ： 6 was conducted. And the wavelet analysis was used to remove the noise information in acoustic emission signal. On this basis, the activity and fractal characteris- tic of acoustic emission in the fai].ure process of samples were studied, The research showed that the characteristic parameter peak of acoustical emission without de-noising would appear cartier. With the increase of space dimensions, the fractal dimen- sion showed a tendency to increase firstly and then stabilize. The fraetal dimension of acoustic emission sequence decreased sharply when the stress approached to the peak. At this time, the specimen appeared main rupture. Moreover, fractal dimen- sion presented a tendency to fluctuate firstly and then stabilize as the specimen in the early stage of instable failure. And this feature provided a basis for the application of fractal theory in safety monitoring of filling mining.