Study On Ground Pressure Appearance Law And Slope Control Of 85205 Large Mining Height Face In Sandaogou Coal Mine

Aiming at a series of safety problems such as roof breaking,gangue leaking between supports,coal wall and end roof falling during weighting period in Sandaogou Coal Mine,taking 85205 high mining face in Bapan District of Sandaogou Coal Mine as the research object,this paper makes a thorough analysis of 5-2 large mining face in 85205 high mining face by means of literature investigation,theoretical analysis,FLAC-3D numerical calculation,physical test and field measurement,etc.The law of strata pressure appearance and the control technology of coal wall slice in coal seam mining.Firstly,by analyzing the geological conditions of the stope,the first weighting step of the basic roof is 82.94～109.72 m,and the periodic weighting step is 12.69-15.88 M.Further,the support pressure of the coal wall is analyzed,and the development of the deformation of the coal wall is divided into three stages:elastic deformation,plastic failure and stability.Secondly,numerical simulation method is used to simulate and calculate the distribution of abutment pressure of coal wall and the failure state of overburden structure during the advancing process of working face.The calculation shows that during the weighting period,the abutment pressure of coal wall increases from 7.5 MPa before weighting to 14 MPa,which is about 6 m in front of the coal wall.The coal wall changes from elastic state to plastic state,and the plastic failure of coal wall begins to occur.Enhanced capacity.Then,the influence range of the advance abutment pressure of the working face is 0-72m and 0-30m is the main influence range of the abutment pressure.The peak pressure is 11 m above the working face,and the peak pressure is 15 Mpa.The coal wall mainly occurs in the middle of the working face and on the side of the two parallel grooves,and the return air is along the groove.The pressure in advance section is larger,especially in the joint roadway section,the sound of coal wall is frequent.Based on the analysis of mechanics mechanism of coal wall,it is concluded that the mining height of 0.578 times at the interface between coal seam and its upper strata is the area prone to occurrence of slice.Based on the analysis of the experimental data of coal strength,it is determined that the coal wall of 85205 high mining face belongs to class Ⅲ unstable coal wall.Finally,combined with the comprehensive analysis of the working face situation,the"six necessities"management technical measures of the sheet-proof Gang during equipment maintenance and the comprehensive prevention and control methods such as improving the initial support force,setting up protective net and dynamic omni-directional monitoring during weighting period are put forward.The research results have certain reference and application value for the control and control of face slope and safe mining in Sandaogou Coal Mine.