Study On Strata Behavior Law Of Double Face Fully Mechanized Mining Face In Luning Coal Mine

In this paper,the 22116 double air face of Luning Coal Industry of Lu 'an Group is taken as the research object.Combined with the means of field data monitoring,theoretical analysis and numerical simulation,the ore pressure behavior law of 22116 double air face is obtained,and then the reasonable mining scheme and support suggestions are given.The main conclusions of this paper are as follows:(1)The gray medium grained feldspar quartz sandstone at the bottom of the upper member of Yungang formation is the main key layer,which controls the movement of all overlying strata;the 23.0m fine-grained sandstone of Datong formation is the sub key layer,which controls the average thickness of overlying strata of 70 m.Whether the main key stratum is broken or not in the double free working face has an important impact on the safety of the working face.(2)Thick and hard basic roof has not only bending moment,shear force,but also shear moment in coal wall of working face.The force of periodic fracture of basic roof on coal wall and hydraulic support of working face is extremely complex.It is necessary to control the spalling caused by bending,torsion and shear failure of coal wall and the stability of hydraulic support during periodic weighting.(3)The field monitoring results show that with the continuous advance of the working face,the pressure law of the upper hydraulic support 2 #,10 #,18 #,27 #,36 #,the middle hydraulic support 45 #,54 #,63 #,72 #,the lower hydraulic support 81 #,90 #,99 #,108 #,117 #,and the overall support resistance of the upper 18 # hydraulic support and the lower 90# hydraulic support is higher than that of other hydraulic supports,while that of the middle hydraulic support is higher The hydraulic support is basically in a stable state;the roof pressure in the upper,middle and lower part of the inclined working face is constantly transferring and changing,so it is necessary to adjust the initial support force and other necessary safety measures according to the actual conditions of the site;through the analysis of monitoring data,it is concluded that the periodic weighting step is about 50 m,which has a great impact on the roadway during the weighting period,and it should be improved in this area during the mining period Advance support is required.(4)The simulation results show that,with the continuous advancement of the working face,the pressure in front of the coal wall,on both sides of the working face and the coal pillar is large.During the mining period of the double free working face,the coal pillar and the upper and lower roadways should be reasonably and effectively supported,and the dynamic of the hydraulic support should be paid attention to at all times,and the initial support force of the support should be adjusted according to the needs,so as to ensure the safe production of the working face.(5)Under the same support condition,when the mining speed is about 6 meters,the hydraulic support bears less overburden pressure;on the contrary,when the mining speed is higher,the hydraulic support bears more overburden pressure,which shows good synchronization;and the mining speed has an important impact on reducing the rib spalling.Under different support conditions,with the increase of support resistance of hydraulic support,the deformation of coal wall gradually decreases,showing a good inverse relationship between them.