Research Of Mechanism And Controlling Technology Of Rock-Burst Induced By Island Boundary Coal Face

Since the large-scale coal mining areas in our nation mine in forms offormal-mining-layout and large-scale-mechanization, a large amount of marginal coal segmentsand island coal segments have been emerging. The extraction of these sections has great socialand economic value to increasing the mine recovery and resources utilization rate andprolonging the mine service-life. The marginal and island coal segments owns the specialconditions of large-area goaf around them, so that the mining of these segments is under highrock burst danger. Based on the marginal and island coal face4318of Xing Long Zhuang coalmine, and by means of theoretical analysis, numerical simulation, laboratory experiments, fieldpractice and other measures, the paper has done a comprehensive study on the surrounding rockstructure characters, the principle of surrounding rock stress change and overburden stratamovement rule on rock-burst, the narrow coal pillar design of gob-side entries, thecountermeasures for entry unsymmetric supporting and other issues about marginal and islandcoal face.The overburden strata of the island coal face showed T type structure in vertical directionand anti-arc-shaped overburden strata in the ends of the coal face according to the O-X rules ofthe overburden strata failure in this paper. The concentration of the advanced support pressureand lateral support pressure were higher under the anti-arc-shaped coal body in the ends of theisland coal face than normal face, and effected by the goaf around. The results could lead to therock burst during the island coal face due to the stress and impact load.The simulation studies surrounding rock stress change and strata movement rules in theprocess of mining. when primary mining marginal coal segments of island coal face, immediateroof and basic roof rupture firstly in the advanced coal wall which is in the middle of the coalwall, the basic roof breaking range largely than the immediate roof, the abutment pressure istransferred to the front of the coal wall, lag coal wall in both ends of the coal wall was curvedrupture, forming o-x rupture. With the mining, the plastic area of strata gradually upward, andforward development, the break of rock strata gradually toward above development.Study proposed the influence of static and dynamic load superimposed is the key of theimpact rupture of marginal coal segments of island coal face. Dynamic load disturbance makesthe coal rock crack, impact, destruction of locking effect, thus together with the static loadleading coal rock system induced impact rupture. Based on the above out prevention andcontrol countermeasures.This puts forward some countermeasure of the prevention and controlof marginal coal segments of island coal faced rock burst happen.Small coal pillar to prevent rock burst has played an important role. Through roof movement law of fully-mechanized sublevel caving mining field and analysis of abutmentpressure distribution laws and bolting supporting technology requirements, analysis of therationality of small coal pillar. Through simulation studies have been different coal pillar width,the vertical stress and the deformation of surrounding rock in coal pillar change law. From theweak structure of the supporting point analysis the supporting mechanism of heterogeneous,and puts forward the roadway along the empty asymmetric supporting principle. From thescope of control of roadway surrounding rock, density of bolt and bolting supporting stiffnessthree aspects, the design of roadway along the empty asymmetric parameters, and proposed adesign calculation expression.In the mining process of4318island coal face, XingLongZhuang Colliery. We divided thedangerous areas of rock burst, used the small chain pillar, designed the parameters of roadwaysupporting such as supporting areas, supporting density, supporting stiffness etc. We alsoconducted the implementation. During the mining process of island coal face, we used themonitoring measures of rock burst and pressure-relief measures to ensure the safe production ofthe4318face and achieve good social and economic benefits.