科研之友
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摘要
In-seam seismic survey is a technique used to investigate the geological structures within coal seams. Dispersion analysis is key method to channel waves processing. In this paper, in order to make the comparison of different dispersion analysis methods, several steps have been taken. First, we acquired the theoretical dispersion equation and curves of SH transmitted channel waves by creating a coal-rock-coal model, setting boundary conditions, and solving wave equations. Then, using finite difference method of staggered grid, we performed the numerical simulation of the channel waves. In the light of three time-frequency analysis methods, namely, short-time Fourier transform, multiple narrow-band filtering and S transform, we transformed one-dimensional time-domain signal into two-dimensional time-frequency spectrum. Finally, converting from time to velocity, we figured out the relation of the group velocity and frequency so as to realize dispersion analysis of channel waves. By comparing the dispersion images of the three methods, the short-time Fourier transformation is flexible in the selection of time window while its resolution is limited in low frequency section, and the multiple narrow-band filtering is flexible in the selection of frequency window but its resolution is low in high velocity section, and S transform makes a balance between high frequency and velocity resolution, and its window length is determined by inherent feature of channel waves. Based on dispersion analysis of SH transmitted channel waves in coal mine field experiments, it can be concluded that S transform dispersion analysis could be used as an effective method.
- 出版日期2016
- 单位中国矿业大学（北京）; 安徽大学
