不同受力状态下岩石破坏过程次声信号特征

采用室内试验方法，分别开展了岩石在压缩、剪切和拉伸状态下的破坏试验，利用高灵敏度的次声信号采集设备同步采集岩石破坏过程中的次声信号，对不同受力状态下岩石次声信号的特征差异进行了研究。结果表明:在压缩状态下，岩石次声信号发射主要在弹性和塑性变形阶段，次声信号的峰值频率在7 Hz左右，在岩石临近破坏前，次声信号振幅和频率范围均有所增加；在剪切状态下，次声信号主要集中在峰值后应力逐步下降的阶段，信号功率分布集中程度较压缩试件略低，峰值频率在8 Hz左右；在拉伸状态下，试件加载初始阶段便有次声信号发生，次声信号频率通常存在高、低两个中心，其中低频与压缩试件接近，高频则高出3 Hz，拉伸试件内部裂隙的萌生和发展较压缩和剪切状态下更为迅速、有序，随着试件内部裂隙的发展，次声信号频率逐渐升高。以上特征的发现为不同受力状态下次声信号的识别以及岩体灾变预测提供了依据。

Infrasound Signal Characteristics of Rock Failure Under Different Stress States

The test of rock failure under compression, shear and tension states was conducted in laboratory, and the infrasound signal during the destructive process was collected synchronously by the high sensitive collection system, and then the difference of infrasound signal under different stress states was studied. The results show that the infrasound signal appears mainly in elastic and plastic deformation stages under compression state, the peak frequency of infrasound signal is about 7 Hz, and the amplitude and frequency range keep rising before rock failure; the infrasound signal appears mainly in the stage of shear stress decreasing under shear state, the concentration of signal power is slightly less than that under compression state, and the peak frequency is about 8 Hz; the infrasound signal always associates with the whole loading process under tension state, and there are two bands of peak frequency, the lower band is close to compression test specimen, and the higher band is more than 3 Hz, the initiation and development of cracks are more rapid and orderly, and the frequency of infrasound signal keeps rising with the development of cracks. All the above characteristics provide a basis for the identification of infrasound signal and disaster prediction of rock under different stress states.