Mechanics mechanism of rock burst caused by mining in the variable region of coal thickness

Rock burst is prone to easily occur during mining in the geological structural area. Thus,the mechanical model of coal-rock combination is established,the influences of coal thickness variation on the distribution characteris- tics of abutment pressure and the evolution law of impact energy are studied,and the rock burst’s mechanism of min- ing in the variable region of coal thickness is revealed. Results show that the in-situ stress in the thinning area is larger than that in the thickening area,and the stress gradient increases with the increase of coal thickness reduction rate or elastic modulus ratio between rock and coal. When mining from thick to thin seam,the abutment pressure shows a “double peak” distribution,but when mining from thin to thick seam,the abutment pressure shows a “ single peak” distribution. When mining from thick to thin seam,the high-energy area formed by the second peak stress area will hin- der the energy from transmitting into the deep coal wall,which will cause the impact energy mainly release into road- ways or working faces,but when mining from thin to thick seam,the impact energy can transmit into the deep coal wall,and the disaster’s influencing scope is small. Field case analysis and field application show that mining from thin to thick seam is advantageous to control the rock burst.