不同加载路径下岩石次声信号特征研究

Study on Infrasound Signal Characteristics of the Rock Failure under Different Loading Paths

为了研究岩石破坏过程中次声信号特征,进行了单轴压缩试验、斜剪试验、巴西劈裂试验3种室内试验,同时采集次声信号,并对采集的次声信号进行小波分解与重构,获得频率为0~16Hz的次声时域信号。通过试验结果分析,发现岩石在剪切破坏形式下能产生突出次声波信号,次声信号强度在应力峰值点附近达到最大;岩石在加载破坏过程中产生的次声信号主要频带能量分布在1~4 Hz,在应力初始阶段1~4Hz频带能量占比达50%左右,随着加载应力的不断增大,这一频带能量占比越来越大,峰值点附近可达85%以上。分析结果表明,次声信号频带能量百分比与岩石所处应力水平有很大关联性,这一频带能量特征可以作为判断岩石受力状态的判据。

In order to research the sound signal characteristics of rock failure, three types of indoor tests were carried out, including uniaxial compression tests, inclined shear tests, Brazilian split tests. At the same time infrasound signal were collected, and the collected infrasound signals were conducted wavelet decomposition and reconstruction, which could get the infrasound time domain signal with the frequency of 0-16 Hz, According to the results of uniaxial compression tests and inclined shear tests, it found that exceptional infrasound signals were produced, when the rock was damaged by inclined shear failure form, and the maximum strength of infrasound signals was around the peak value of stress. In the process of rock loading damage, the energy distribution of main frequency of infrasound signals was in 1~4 Hz. At the initial stage of stress, the frequency energy of 1-4 Hz accounted for 50%, and with the constant increase of loading stress, the proportion of this frequency energy was getting more and more large, even to reach more than 85% around the peak value. The analysis results showed that there was a great correlation between the proportion Of energy frequency of infrasound signal and the stress levels of rock. And the energy characteristic of this frequency could be a critical basis for the stress state of rock.