Numerical Simulation Research Of Coal And Gas Outburst Near Tectonic Region In Ping Ding Shan Mining Area

Through analyzing coal and gas outbursts near tectonic region in Ping ding shan mining area, founding that coal and gas outbursts have a regular when coal face pass the geological structure, namely coal and gas outbursts are more likely to happen when coal face advance from fault downthrown side to uplifted side; coal and gas outbursts tend to occur in small fall tomography. The traditional coal and gas outburst mechanism, for example "earth stress theory"、"tectonic stress theory", which can’t explain why coal and gas outbursts have directivity. Through analyzing the phenomenon found that coal seam gas pressure、in-situ stress、the strength which are the basic condition that lead to coal and gas outburst happen, the gas release condition which is the determining factor affects the accident.; the coal seam is the main release channel latterly, and the form of gas release channel changes which affect the release of gas. Article using the RFPA2D numerical simulation software to study the coal face through fault from downthrown side to uplifted side and from uplifted side to downthrown side, the results showed that:(1) Coal face through thrust fault from downthrown side to uplifted side, thrust fault’s fall is 1.3m, about a third of the coal seam thickness, the gas release channel is not the worst when coal face advanced near the fault. coal and gas outbursts happened near the fault in the process of coal face advanced; Fault occurs tensile failure under the ction of concentrated stress, the coal seam occurs shear fracture under the action of shear stress and gas pressure, coal structure suffered severely damage, it made the gas eleasing channel and form change, which made methane accumulate in coal and can’t elease under the fault sealing process, which improve the gas pressure and lead to coal and gas outbursts happen under gas pressure. When coal face through normal fault from downthrown side to uplifted side, normal fault’s fall is 2.6m, it is about 3/5 of coal seam hickness, the gas releasing channel is in the semi-closed state, and the ability of gas eleasing is relatively poor and methane accumulate in which made the gas pressure mprove. Coal seam occurs compression-shear failure under shear stress and gas ressure, coal is thrown under the action of gas pressure when reveal the fault.(2) When working face through fault from uplifted side to downthrown side, fault and coal seam broken seriously under concentrated stress, and the gas releasing channel and form was good, and gas released well, coal and gas outbursts didn’t happen when evealed the fault; with advancing of coal face, when it was near the bottom protruding, he gas pressure relief belt disappeared, the inhibition of bottom protruding which made gas release difficult, and made gas accumulate, and made coal face in high gas pressure state, coal and gas outburst happened under the high gas pressure.(3) Coal and gas outburst is not in the best close condition when it happened in the elevation, it is likely to happen to shallow once has the best sealing condition, even the strength of coal and gas outburst would be strong.