Abstract:The effects of frequency in different range of frequency bands on attenuation coefficient are different. The filter properties of stress wave propagating in intact rock mass within the scope of log frequency are studied through the field test. Based on the shortcoming of common viscoelastic model predicting the relationship between attenuation coefficient and frequency, Maxwell model adopting unsteady viscosity coefficient is established after the unsteady calculation of viscosity coefficient is performed. The filtering effect of improved model is evaluated using waveform correlation coefficient. The study results indicate that intact rock mass have a low pass filter property and unequal interval band-pass property within the scope of low pass filter. The number of band-pass decreases with the increase of propagation distance. Attenuation coefficients of stress wave with frequency change greatly in the transition zone of absorption frequency. The change rule of attenuation coefficient of stress wave propagation in intact rock mass is effectively described using improved Maxwell model containing unsteady viscosity coefficient. The boundary frequency in the transition zone of absorption frequency has negative index relationship with propagation distance. The edge gradient parameter in the transition zone of absorption frequency is approximately constant. The filtering effect of intact rock mass improves obviously using improved Maxwell model with the increase of propagation distance. The waveform correlation coefficient reaches to 0.89 when propagation distance of stress wave is 4.75m. The improved model is capable of describing the properties of intact rock mass.
王观石 胡世丽; 李志文 王星光 . 完整岩体对测井频率应力波的滤波特性[J]. , 2014, 33(23): 127-132.
WANG Guan-shi HU Shi-li; LI Zhi-wen WANG Xing-guang. Filter Property of Intact Rock Mass to Stress Wave within the Scope of Log Frequency . , 2014, 33(23): 127-132.