Study On The Principle Of Surrounding Rock Stability And Filling Parameter Of Fully Mechanized Coal Mining Face Through Abandoned Roadway In No.1 Coal Mine Of Yangquan Coal Mining Group

For a long time,the technology for passing through abandoned roadway in stope has been a problem difficult to be dealt with.However,with the increasing decrease of coal resources,it is much necessary for the coal existing in the abandoned roadway to be mined.Yet,it is very dangerous to do that,because the lead abutment pressures will deform the roof baseboard and two sides of the abandoned roadway very much.What's more,it is also dangerous to work in stope with the stope gradually advancing into the abandoned roadway,such as the accidents of roof collapse in large area,or supports collapse under great pressure,which happens a lot and brings danger to miners.Based on the traditional technology for passing through abandoned roadway,this thesis uses an integrated method of theoretical analysis,numerical simulation and industrial test to explore the necessity of reinforcing the abandoned roadway passed in8303 working face in No.1 Coal Mine of Yangquan Coal Mining Group,to study the instability mechanism of main roof of passing through the abandoned roadway,and the partial stowage of high-water content materials.Firstly,based on the specific geological conditions of the No.1Coal Mine,a numerical calculation model was made to simulate the stope in the abandoned roadway without the reinforcement.With the stope advancing into the abandoned roadway,the damage of its wall rock was analyzed affected by the work of stope.Also,monitored was the working resistance of hydraulic support which varies with the distance between the working face and the abandoned roadway.In the end,reinforcement measures of the abandoned roadway were proposed after a comprehensive analysis.Secondly,the method of theoretical analysis was used to model the instability stress of the main roof in the abandoned roadway,and analyze the instability mechanism of main roof of passing through the abandoned roadway;and thus the critical point of supporting resistance was obtained to maintain the stability of wall rock of the abandoned roadway.And then the economical,effective technology of partial stowage of high-water content materials was proposed;the method of numerical modeling was used to explore the length parameters of backfill from the three aspects: the deformation of the roof baseboard and two sides of the abandoned roadway and the roof of working face,stress between the working face and the rear of the abandoned roadway,and the distribution law of the plastic zone.Besides,the distribution law of the lead abutment pressures after the working face passed through the abandoned roadway was studied,verifying that the partial stowage of high-water content materials in the abandoned roadway can effectively reduce the effect which the lead abutment pressures of working face hold on the roof of the working face and the wall rock of the abandoned roadway.Finally,the experiment of the partial stowage of high-water content materials in the abandoned roadway was conducted in 8303 working face,and the observationscheme of mine pressure was formulated.After a monitoring and analysis of the impact which the support resistance of working face and backfill have on coal pillar pressure,the effect of the partial stowage in the abandoned roadway has been proved,showing that the parameters and technology of the partial stowage in the abandoned roadway are reasonable and valid,and this kind of technology of partial stowage in the abandoned roadway can be widely used under similar conditions.