Meikuang Anquan (Dec 2023)
High stress zone detection technology of coal face based on seismic slot wave and P-wave
Abstract
As the coal mining area shifts towards deeper depths, mining depth continues to increase, mining conditions become more complex, and ground pressure disasters become increasingly severe. There is an urgent need for accurate detection methods capable of spatially detecting high-stress areas in coal mining faces. Through uniaxial compression test, the variation of seismic longitudinal wave velocity of coal and rock samples under uniaxial compression was studied. It was found that during the elastic stage of uniaxial compression, the axial seismic longitudinal wave velocity of coal and rock samples increased with increasing stress until the coal and rock blocks were damaged, and the wave velocity rapidly decreased. The response curve of seismic wave velocity to stress showed that there was a positive correlation between seismic longitudinal wave and stress during the elastic stage of coal and rock samples; at the same time, the response curve characteristics of seismic slot wave velocity and stress under uniaxial compression conditions were also studied, and it was found that there was a positive correlation between seismic slot wave and stress, which could also be used for exploring high-stress areas in coal mining working face. It is proposed to use seismic slot wave and longitudinal wave together to detect stress concentration areas. Simple geological conditions of coal mining working face were selected for high-stress detection experiments, and the initial arrival speed of longitudinal wave and the speed at a specific frequency of slot wave were extracted from the test data. After CT tomography imaging, a contour map of wave velocity was formed. Then, combined with the relevant information of roadway, the high-speed area was circled respectively, and according to the positive correlation between seismic wave velocity and stress, the high-speed area was interpreted as a high-stress area. Finally, the overlapping area of the two was taken as a high-risk area of impact ground pressure in the working face. Through drilling and mining verification: when drilling in the stress overlap area, the amount of coal powder was obviously larger, easy to shrink holes; when mining passed through the stress overlap area, the deformation of roadway was relatively large, and “coal cannon” occasionally occurred. The joint exploration test shows that trough waves can be used to detect high-stress areas in coal mining working face, and combining longitudinal waves can overcome the limitations of single geophysical exploration means and more accurately detect high-stress areas in impact ground pressure mines.
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