JIA Zeqing1, 2, WU Zhenjun1, TANG Hua1, CHENG Xu1, 2, WANG Teng1, 2
Journal of Vibration and Shock. 2024, 43(21): 245-252.
The vibration signals generated during the percussion-rotary drilling process often contain rich rock mechanics information, and there is a lack of quantitative research on identifying rock mechanics properties through vibration signals. The vibration signals of three different directions during the drilling process were collected through engineering examples, pure drilling process signals were extracted through the displacement curve of the drill rod, noise was eliminated through wavelet transform, the time-domain, frequency-domain, and time-frequency domain characteristics of the drilling process vibration response was analyzed, amplitude domain parameters that depend on the shape of the probability density function were introduced, and representative characteristic values and frequencies were identified. The relationship between the time-frequency characteristics of drilling process vibration and rock mechanical properties was analyzed through rock mechanics test results. The results show that the mean, standard deviation, and effective values of the average level of vibration intensity in the 3D vibration signal increase with the increase of uniaxial compressive strength of the rock, while the peak factor, impact factor, and margin factor, which reflect the proportion of impact signals, decrease with the increase of uniaxial compressive strength of the rock; The mean, standard deviation, effective value, peak factor, impact factor, and margin factor of the axial vibration signal of the drill pipe exhibit a good linear relationship with the uniaxial compressive strength of the rock. It is feasible to predict the rock strength through these time-domain characteristic values; The axial characteristic frequency of the drill rod is equivalent to the impact frequency of the drill bit, and the characteristic frequency perpendicular to the direction of the drill rod shows significant differences. The time-frequency analysis results show that the characteristic frequency remains basically unchanged during the drilling process for uniform stratigraphic conditions; the characteristic frequency perpendicular to the direction of the drill rod exhibits a nonlinear relationship with the uniaxial compressive strength of the rock, the strength of rocks can be determined by combining drilling speed.
