Quantitative response characteristics of transmitted in seam channel wave in coal seam with faults

Hidden disaster causing geological factors affecting coal mining mainly include faults,collapse columns,sudden changes in coal seam thickness,stress concentration areas,etc. Accurately and quantitatively identifying these geological abnormal bodies can provide a geological guarantee for safe and efficient mining,which is also the core content of the high yield and efficient geological guarantee system of coal mines in China. Safe and efficient production of coal mines urgently requires that the hidden disaster causing geological factors such as small faults,coal seam thickness changes,collapse columns,in situ stress concentration areas,gas enrichment zones,fracture development zones,etc. can be identified in advance and quantitatively. The underground channel wave seismic detection technology in coal mines has achieved good geological results in the detection of hidden structures in coal mining faces,but this technology can not realize the quantitative identification of the “three elements” (fault throw,dip angle and inclination) of faults and the direct measurement of coal thickness. It is urgent to carry out relevant research to overcome this technical bottleneck. From the point of view of numerical simulation,this paper analyzes the influence of faults with different coal thickness and fault throw on the dispersion and energy of Rayleigh transmitted channel wave and Love transmitted channel wave,and then studies the quantitative relationship between fault throw and energy attenuation of transmitted channel wave. The results show that:① The vertical faults do not affect the dispersion characteristics of channel waves,but only have a significant impact on the energy of channel waves. ② The simulation shows that even if the fault throw is greater than the coal thickness,there will still be considerable channel wave energy passing through,especially the long wavelength component. ③ When the channel wave wavelength is close to the coal thickness,the attenuation of the channel wave by the fault with the same normalized fault throw does not change with the channel wave length,and the attenuation of Love channel wave and Rayleigh channel wave are almost the same. ④ When the equivalent q is used to describe the attenuation effect of faults on channel wave energy,the normalized fault distance σ has an inverse relationship with the square root of Q. The research results in this paper can provide theoretical support for the quantitative detection of fault throw of transmitted channel wave. However,the above results are only based on theoretical simulation,and further research is still needed when they are used in actual exploration. The future research is to study how to apply the quantitative relationship of fault throw proposed in this paper to realize the quantitative detection of fault throw in actual data.