Study On Support Technique Of Mining Roadway In Xuemiaotan Coal Mine

At present,Xuemiaotan coal mine mainly exploits 30303 working face.The thickness of the mining coal seam is 6m.Bolting net support is adopted.The support scheme is determined according to the support scheme of adj acent mines.The coal seam cannot be suspended on the rock layer,and the roof may be unstable and collapsed on a large scale.There is the possibility that the roadway roof may collapse or oversupport in a wide range of instability.The research methods of the combination of surrounding rock mechanics parameter test,mechanical model analysis,loosening ring range test,similar material simulation experiment and numerical simulation were adopted in this paper to obtain the support optimization plan of the mining tunnel in 30303 working face of Xuemiaotan coal mine.The conclusions of the main research are as follows:(1)The rock samples and coal samples from the roof and floor of the tunnel at 30303 working face were collected on-site,the mechanical parameters were measured,and the surrounding rocks were classified.The results show that the attribution of coal seam,direct roof and floor are extremely hard coal,medium stable roof of type 2b,and hard floor of type V,respectively.Through on-site observation of ore pressure and study of ore pressure law,the influence range of mining movement on the working face is 100 meters,the leading stress area of the working face is 25 meters,when it is 7 meters away from the working face,the maximum increment of bolt dynamometer is 19kN.The main roof has a periodic pressure step distance of 9?18 meters.The roof of the roadway has no roof caving phenomenon,and the side of the coal pillar 5m away from the working face has a small side,indicating that the surrounding rock of the mining roadway is stable.(2)The elastic wave test and borehole peep test were carried out,the range of the loose circle at the top of the roadway was determined to be 0.8m,the side of the coal pillar was 0.9m,and the side of the coal wall was 0.6m.It was determined that the surrounding rock of the roadway in the 30303 working face was class ? relatively stable,and only "bolt+anchor net" was needed for support.(3)The similar material simulation experiment was adopted to observe and analyze the destruction mode of the tunnel,and the conclusion that the roof center of the tunnel was the key support area was obtained.The structure model of solid supported beam is established for the roadway roof,and it is obtained that the maximum normal stress on the rock beam section is less than the tensile strength of rock strata,so the rock beam structure will not be destroyed,that is,the roadway roof is stable.(4)The optimized support parameters of the mining tunnel were obtained through theoretical calculations.Compared with the field implementation scheme,the optimized scheme has two fewer bolts at the top and both sides,and the row distance is increased from 1.0m to 1.4m.The cost can be saved by 70675.5 yuan per 100m of tunnel,which has obvious advantages in economy.Through numerical simulation experiment,the distribution characteristics of roadway stress and the moving quantity of roof,floor and two sides under the support of the field implementation plan and the optimized design plan are analyzed,and it is concluded that the field implementation plan is sufficient to bear the load of roadway strata,but there is the problem of excessive support.The optimized scheme can provide sufficient support strength,and the control effect of the two sides and roof of roadway is good,making the support more economical and reasonable.(5)Through the test of bolt dynamometer and displacement of roadway roof and two sides,and the monitoring of support resistance near the roadway,the optimized scheme can provide sufficient support strength,and the control effect of roadway roof and two sides is good,which meets the engineering application.