Study On Laws Of Pressure Behavior And Surrounding Rock Control Technologies Of Narrow Pillar Of Mining Roadways In Island Coal Face

China’s large coal mine production using formal mining layout, large-scale machinery of production, in order to ensure the normal operation of coal mining face, avoiding the mutual interference between the continual mining working face, sometimes mining area would use the way of skip mining continuation, thus leaving the residual coal and isolated working face. Improve the coal recovery rate and prolong the life of the mine of these isolated island working has great social and economic value. Because both sides of the isolated island working face are mined out, the stress concentration degree of working face and the damage of surrounding rock will be serious while mining, which cause great harm to the safety of working face. Based on the isolated island coal face 3205 of Bo’fang coal mine, through theoretical analysis, numerical simulation and field practice method analysis the structure characteristics of surrounding rock structure characters, the principle of surrounding rock stress change and movement rule of overlying strata, the narrow coal pillar design and roadway supporting rationality analysis. The main research results are as follows:(1) The overlying strata of 3205 isolated working face has symmetrically "T" type structure of short arm, under the influence on the both mined sides, the working face advance abutment pressure and lateral abutment pressure concentration factor are all higher than the normal face, influenced by mining.(2) Numerical simulation study on the stress change of surrounding rock, overburden failure law and the law of stress distribution of surrounding rock under different width of coal pillar. At the beginning mining of the isolated island working face, The main roof started being broken on the both end sides, and then spread to the surrounding, finally form the O-X type breaking. When the coal pillar width is certain, with the working face advancing, the abutment pressure increasing and then decreases continuously and finally showed a stable trend; When the coal pillar width is 6m, 8m, 10 m, 15 m, 20 m, 25 m, the working face advance the same distance, the stress concentration degree and the deformation of roadway surrounding rock are maximum when the width of coal pillar is 8m; the concentration degree of the coal pillar is minimum when the coal pillar width is 6m; the stress concentration degree of the coal pillar is maximum when when the coal pillar width is 15m; the stress of the coal pillar is in a saddle shape, and the peak of the lead at the end of the end is greatly decrease d when the coal pillar width is 20 m and 25 m.(3) Field test results show that the weighting of the working face end is stronger than the middle of the working face, the weighting step is short; The influence range of working face in advance support pressure is about 40 m, the mining roadway deformation is mainly in two sidewalls, it can.meet the production requirement under the action of bolt support.