Abstract

The control and prevention of rock burst in a steeply inclined coal seam are essential. In order to figure out the effects of filling and mining sequence on rock burst in the steeply inclined coal seam, B3+6 and B1+2 coal seams in Wudong coal mine are chosen as the research objects, and an in-house experiment system of similarity simulation is established in this study. Combined with numerical simulation, the characteristics of collapse, stress distribution, and displacement variations can be measured, which provide useful information to study the effects of the filling body and mining sequence on rock burst. Experimental results show that the key reason for rock burst in a steeply inclined coal seam is the stress concentration of the rock pillar between B3+6 and B1+2 coal seams instead of the stress-lever-effect of a deeper rock pillar. The filling body can support the middle rock pillar, share the geological structure stress in the horizontal and vertical direction, eliminate the stress concentration zone largely, and prevent the occurrence of rock burst. When multiple working faces are working, the opposite side of the coal seam should be mined first to release the energy in the rock in advance, thus preventing the rock burst effectively. The research results provide fundamental information for better understanding the reason for rock burst and preventing rock burst in the steeply inclined coal seam.

Highlights

  • Several rock bursts have occurred frequently during mining, especially in steeply inclined coal seams [1]

  • Rock burst occurs at a depth that is shallower than the critical mining depth (500 m), making the mining of steeply inclined coal seams very difficult [2, 3]

  • Since September 2009, more than 10 rock bursts have occurred at B3+6 coal and B1+2 coal working faces at 300 m to 350 m depth [7]. e prevention and control of rock burst in steeply inclined coal seams have become an urgent problem

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Summary

Introduction

Several rock bursts have occurred frequently during mining, especially in steeply inclined coal seams [1]. E prevention and control of rock burst in steeply inclined coal seams have become an urgent problem. E important role of the dip angle and the width of the coal pillar in the rock burst have been proposed, especially in inclined coal seams [11, 12]. Combined with the numerical simulation, the mining sequence and the filling body on the rock burst in steeply inclined extrathick coal seam were studied to prevent and control the rock burst in a similar steeply inclined coal seam. B3+6 and B1+2 coal seams are typical steeply inclined extrathick coal seams. e top-coal caving method has been used for mining. e height of the horizontal section is 25.0 m. e top-coal caving workings in the horizontal section are located beneath the multilayer mined-out area. e goaf is filled with yellow soil and has a space of 50 m under the surface (Figure 1)

The Similar Simulation Experiment
Tunnels Mining faces
Numerical Simulation
Results and Discussions
Conclusions

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