Abstract
Promoting the ability of anti-bursting of the confining rock of a coal roadway is of significant importance to the safe production of a coal mine. In particular, in deep-buried coal mines, highly frequent rock burst occurs due to large earth pressure and complex geological conditions, which needs serious improvement. This paper investigated a type of confining rock modified method, which can modify the physical properties of the surrounding rock and form a crack region and a reinforced region by blasting and grouting reinforcement. Based on a set of physical model experiments and numerical modeling, the results of a comparative analysis between a normal roadway and the modified roadway in the static stress redistribution, dynamic stress, damage evolution, and energy dissipation suggest that the modified confining rock is capable of protecting the coal roadway against rock burst from roof stratum, obviously reducing and transferring the concentered static–dynamic stress out of the cracked region, dissipating the dynamic energy by plastic damage in the cracked region, and keeping the integrity of the reinforced region. In addition, the velocity of the dynamic stress vibration wave at the surface of the modified coal roadway is obviously reduced, which is beneficial for decreasing the movement of cracked rock blocks and protecting the lives and goods in the coal roadway.
Highlights
Rock burst during coal mining is a typical dynamic disaster that threatens the safety production seriously in coal mining country [1,2,3,4]
With the growth of mining depth, bolt–anchor systems associated with grids by steel belts, arched sheds or hydraulic support are primary applied against the large displacement or broken zone induced by large in situ stress, while such traditional roadway supports were normally designed in the view of static pressure [6,7,8,9]
The damping rock bolts release a certain degree of strain energy by sliding friction or damper [21,22,23], the hydraulic devices act as dampers that release dynamic stress from confining rocks, thereby stabilizing the coal roadway [24], and the retractable steel sheds bear the load from confining rocks and dissipate the dynamic stress by its retractable structure [25,26]
Summary
Rock burst during coal mining is a typical dynamic disaster that threatens the safety production seriously in coal mining country [1,2,3,4]. The damping rock bolts release a certain degree of strain energy by sliding friction or damper [21,22,23], the hydraulic devices act as dampers that release dynamic stress from confining rocks, thereby stabilizing the coal roadway [24], and the retractable steel sheds bear the load from confining rocks and dissipate the dynamic stress by its retractable structure [25,26]. The B2 coal seam is the Background primary excavating source, whose average thickness and dip angle are 5.6 m and 14◦ , The geological ofby the Kuangou coal that mine weresee taken respectively.
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