基于小波分解的岩石破坏次声信息特征研究

次声探测是近年来在自然灾害临灾预警领域兴起的一种新方法,具有广阔的前景。为了研究岩石破坏次声信息特性,在室内试验的基础上采集了砂岩试件破坏前的次声信号,借助小波分析方法对信号的能量特征进行了分析。结果表明:岩石变形破坏次声信号能量主要集中在4～8 Hz的中频带和8～16 Hz的高频带两个频率范围内,中频带能量大于高频带能量,同时在低频带0～4 Hz内也存在一定的能量分布。随着岩石变形破坏程度的增加,次声信号的中低频带能量在相对减少,在岩石临近破坏前,次声信号的中低频带能量与高频带能量的比值接近1。上述特征的发现,为岩石破坏次声信号识别以及破坏前兆预警提供了重要依据。

Characteristics analysis of infrasound before rock failure applying the wavelet decomposition

Infrasound detection is a new method emerging in recent years in disaster prediction field, it has wide application prospect. In order to analysis the characteristics of infrasound before rock failure, the infrasound signals of sandstone failure have been recorded in laboratory, and the energy characteristics of the signals has been analyzed using the method of the wavelet decomposition. The results show that the infrasound energy of rock failure is mainly concentrated in two frequency bands, one is the medium frequency band in the frequency range of 4 to 8 Hz, and the other is the high frequency band with frequency range 8~16 Hz. The energy in the former is higher than that in the latter. And there still have a certain amount of energy in the low frequency band that the frequency range is 0~4 Hz. By comparing the energy distribution in different frequency bands, the infrasound of rock failure can be recognized. With the increasing degree of rock deformation, the energy in the medium and the low frequency bands reducing relatively. If rock failures, the ratio of energy in the medium and the low frequency bands comparing to the high frequency band is close to 1.The discovery of the above characteristics of infrasound during rock deformation and failure provide an important basis for infrasound signal recognizing and failure warning of rock.