Research On Mine Pressure Manifestation And Reasonable Coal Pillar Retention In The Extra Thick Fully Mechanized Caving Face

The Mongolia Dongsheng coal mining of large coal enterprises with regular layout,highly mechanized production,in order to ensure the normal coal face to succeed,to avoid mutual interference between the continuous mining face,mining area between the working face sometimes using skip mining connecting mode,because this left all kinds of residual coal and isolated working face.In these island working face,to improve the recovery rate and utilization rate of coal resources,has important social and economic value to prolong the production period.Because both sides of isolated working face have been mined,so the work in the mining area when the degree of stress concentration,severe destruction of surrounding rock,on the face of safe and efficient mining caused.This paper takes Huainan western mining company Tang Jiahui 61102 island working face as the research background,through theoretical analysis,numerical simulation and field data analysed the island working face surrounding rock structure,the rock shall be reserved and timbering rationality analysis of rock movement,change and cover the rational coal pillar,the main achievements are as follows:(1)The 61102 overlying strata of the isolated island working face have symmetrical"T" structure,which are affected by both sides goaf.The abutment pressure and the lateral abutment pressure concentration factor of the working face are higher than those of the normal working face,and the influence degree of mining is relatively large.(2)Numerical simulation is carried out to study the surrounding rock stress change,overburden failure law and the stress distribution rule of surrounding rock under the condition of different width coal pillar during the mining process of island working face.In the initial mining of the island working face,the old top was damaged on both sides of the end first,then spread to all directions,and finally formed O-X type break.When the width of the coal pillar is certain,with the advance of working face,the abutment pressure first increases and then decreases finally showed a stable trend;(3)When the coal pillar width were 5m,78m,9m,14m,19m,24m,push the same distance of working face,column width is 7m when the surrounding rock stress concentration degree and roadway deformation;coal pillar width is 5m,the minimum column stress concentration degree;when the coal pillar width is 14m,the maximum column stress concentration;when the coal pillar width was 19m and 24m,the coal pillar stress in the shape of a saddle,the ends of abutment pressure peak decreased significantly.(4)Field measurement results show that the working face end is stronger than the middle pressure,and the short distance is short.The influence range of the advance abutment pressure on the working face is about 24m,and the main gateway of the mining gateway is two gang deformation,which can meet the production demand under the support of bolting.