莱州花岗岩应变岩爆实验声发射频谱特征分析

深部岩爆的发生对应着岩石的猛烈破坏,同时产生弹性应力波,相应的就会有声发射现象发生。声发射频谱特征的变化能够反映岩爆发生的本质信息,因此开展此方面的研究有着重要的理论与应用价值。利用自主研发的深部岩爆过程模拟实验系统,进行了花岗岩循环加卸载条件下的岩爆声发射模拟实验。首先对花岗岩的应变岩爆实验过程进行划分,分析其声发射释能特征;其次,选取实验过程中的关键特征点声发射波形信息并对其进行傅里叶变换,观察各关键特征点的原始波形特征、二维频谱特征,寻求岩爆时刻的本征频谱;从其二维频谱功率谱图上,获取各个关键特征点的频谱响应特征和其对应的幅值特征,研究其频谱响应规律。研究结果表明:岩爆时刻区别于其他阶段最明显的特点就是声发射表现为连续型波形,低频高幅值特征。

Experimental Research on Acoustic Emission Spectral Characteristics of Granite Strainbursts from Laizhou

The rock burst occurred in deep corresponding severe failure of rock, also produced the elastic stress wave, there will be acoustic emission (AE) phenomenon. The change of frequency spectrum characteristics of AE is able to reflect the essential information of rock burst; therefore the research has important value of theory and application. The strainbursts test of granite was carried out under cyclic loading and unloading conditions by the deep underground rock burst analogue testing machine, which is independently developed. Firstly, the process of granite strainbursts test was divided and the AE energy release characteristics corresponding to each stage were analyzed; Secondly, the key points of acoustic emission waveform information during the experimental process were collected and Fourier transform were carried out; the original waveform features, two-dimensional spectral characteristics of spectrum for each key points were observed, seeking the AE Eigen-frequency spectrum when rock burst happened; the spectral response characteristics and its corresponding amplitude characteristics of each key feature points were obtained from the two-dimensional spectral power spectra, and the law of the spectral response was studied. The results show that: the most obvious feature when rock burst happened is different from the other stages is that the AE performance for continuous wave, low frequency-high amplitude characteristics.