Forward simulation of unfavorable geological bodies and analysis of waveform characteristics based on time domain finite difference method

Abstract Since there are few advanced detection studies on rock-breaking sources of shaft boring machines, this study establishes a forward evolution model of bad geological bodies based on the time-domain finite difference method(FDTD), and analyzes the waveform characteristics of seismic records by improving the time-frequency analysis method of HHT, and use wavelet variation for result verification, the applicability of this method to seismic signal analysis is verified. Research showed that the energy intensity of the direct wave is much greater than the energy intensity of the reflected wave, the main energy of the direct wave is concentrated between 0 ~ 90Hz, the main energy of the reflected wave is concentrated between 0 ~ 110Hz, and the overall energy of the cave in the bad geological body is the largest