Abstract
To study the reasonable layout of upper protective layer for the prevention rock burst under coal seam group with close quarters conditions, a panel 3203 that belong to Zhongxing Colliery is taken as a typical engineering background. By means of on-site survey, theoretical analysis, numerical simulation, and on-site industrial applications, the reasonable layout of upper protective layer for prevention rock burst is studied. The results show that the overall stress environment of the floor under gob of upper protective layer is good, and the overall stress environment of the floor under the upper side of gob is also good, but the overall stress environment of the floor under the lower side of gob is bad. According to numerical simulation results, an L-shaped stress superposition area is formed in the lower end of panel 3203 under the original layout scheme conditions, and the maximum stress concentration coefficient is about 2.8 in stage I and 4.0 in stage II. A new stress superposition area is formed at the middle to lower end part of advance mining face of panel 3203 for the stage II under the optimal layout scheme conditions, and the maximum stress concentration coefficient is about 2.4; the original L-shaped stress superposition area is gone due the transfer and release of stress, and the optimal layout scheme has a very significant effect on the prevention and control of the subsequent rock burst accidents; the monitoring results of working resistance of hydraulic supports and surrounding rock deformation indicate that the overall pressure relief of the surrounding rock in advanced segment of 3205 tailgate can be effectively realized. The study conclusions provide theoretical foundation and a new guidance for preventing rock burst with similar engineering geological conditions.
Highlights
Rock burst is a typical dynamic disaster that often occurs in deep mining activities, and its obvious characteristic is the process of instant energy release that accumulates in high stress concentration area around the mining space [1,2,3]
Coal and gas outburst is a typical dynamic disaster in deep mining activities, and it is caused by the poor permeability of coal seam under high stress environment
When the gas accumulates to a certain extent in the coal seam, it is easy to have a serious accident under the action of higher gas pressure [4, 5]. erefore, when a coal seam with high gas accumulation and large burial depth, it is easy to induce dynamic disasters under the mining period
Summary
Rock burst is a typical dynamic disaster that often occurs in deep mining activities, and its obvious characteristic is the process of instant energy release that accumulates in high stress concentration area around the mining space [1,2,3]. Shock and Vibration loading characteristics and rock bust instability mechanism of gob-side roadway in deep mining and revealed the “three load” superimposed induced rock burst mechanism of gobside roadway under lateral static load, advanced static load, and disturbed dynamic load of gob; Jiang et al [10] put forward that roadway excavation along gob can effectively improve the stress environment of surrounding rock of gobside roadway, and reduce the maintenance cost of roadway and prevent rock burst accidents; Zhu et al [11] discussed the influence of coal pillar width on rock burst instability and mine earthquake, and the reasonable design basis of coal pillar width based on the cooperative control of rock burst and mine earthquake was proposed. Combined with the geological conditions of panel 3203 in Zhongxing Colliery, this paper theoretically calculates and analyzes the influence of the gob of upper protective layer on the stress disturbance of the floor under the original layout scheme and optimizes the layout scheme of the panel of upper protective layer through numerical simulation and carries out the on-site industrial applications in panel 3205. e on-site mine pressure monitoring results show that the optimized layout scheme of the panel of upper protective layer has a good control effect on the surrounding rock deformation of the gob-side roadway in advanced segment and improves the stress environment of the surrounding rock, which provides a reference and guidance for the reasonable design of the panel of upper protective layer under the coal seam group with similar close quarters conditions
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