Study on advance detection of geological anomaly in development roadway based on Rayleigh wave technology

Abstract

Coal mine safety accidents are very likely to occur when the roadway is excavated through tectonic areas such as collapsed pillars. In this paper, Rayleigh wave technology is used to carry out advance detection in heading face of No.8 joint roadway in Zhangcun Coal Mine 480# mining area. Firstly, the phase velocity of the wave is calculated based on the simple harmonic fluctuation displacement equation and spectral analysis technique, and the dispersion curve is obtained by theoretical calculation with the phase velocity as the horizontal coordinate and the half-wavelength of the wave corresponding to the phase velocity as the vertical coordinate. Based on the finite-difference （FDM） method, we obtained that Rayleigh waves would gather energy at the junction of the collapse column and the surrounding rock, and verified that the Rayleigh wave energy decays slowly and propagates slowly. Secondly, according to the mine geological data and the actual production situation of roadway excavation, it is determined that the overall observation distance is 3.5 m to carry out the Rayleigh wave geological structure detection. Finally, using the comprehensive analysis method of the dispersion curve and the coal seam depth profile, it is concluded that there are 3 anomalies in the geological structure of the 8# connecting roadway in Zhangcun Coal Mine, which are located at 20-30 m, 35-45 m, and 55-65 m respectively. The results of this study effectively guide the safe driving of No.8 combined roadway.

Keywords

• collapsing column
• rayleigh wave
• advanced detection
• wave displacement equation
• safe excavation