Study On Technology Of Cutting Roof To Discharge Pressure And Protect Roadway By Presplit Blasting In Xutuan Coal Mine

The service life of the mining area roadway is long,and it undertakes many functions such as material transportation and pedestrian.The stability control of the mining area roadway is very important for the safe and efficient production of the mine.Aiming at the serious deformation problem of the 83 lower mining area downhill roadway caused by mining stress in Xutuan coal mine,this paper puts forward the deep hole presplit blasting technology of cutting roof and relieving pressure to protect the 83lower mining area transportation and pedestrian downhill roadway by implementing presplit blasting near the stoping line of 7₂314 working face.Through theoretical analysis,numerical simulation,field test and other methods,the main achievements are as follows The results are as follows(1)The structural characteristics of overlying strata of 7₂314 working face in Xutuan coal mine were measured and analyzed.The mechanical property parameters of surrounding rock were mastered.The pre splitting blasting horizon of working face roof was designed.The mine pressure behavior law and stress distribution characteristics of advance support of 7₂314 working face were obtained.(2)The judgment method of blasting damage range is analyzed.The PPV criterion is used to analyze the presplitting blasting range simulated by DYNA,and the calculation formulas of the radius of presplitting blasting fracture zone and the radius of rock mass heavy loss zone are determined.It is concluded that the top cutting effect of 7₂314 working face can be ensured when the designed maximum spacing of blastholes is 13.4m.(3)The FLAC3D numerical calculation model is established,and the stress distribution law of roadway protection pillar under the condition of roof cutting and no roof cutting is compared and analyzed.The surrounding rock deformation and plastic zone development characteristics of 83 lower mining area transportation and pedestrian downhill are analyzed.It is known that the area of high stress area,surrounding rock deformation and plastic zone of roadway protection pillar under the condition of roof cutting are significantly reduced,which verifies the feasibility of roof cutting and pressure relief roadway protection scheme The surrounding rock deformation law of 83lower mining area transportation and pedestrian downhill under different width of roadway pillar is compared and analyzed,which provides guidance for the design of stoping line position of 7₂314 working face.(4)Taking the 7₂314 working face of Xutuan coal mine as the engineering background,the paper designs the layout scheme,construction process and technical requirements of the roof deep hole presplitting blasting boreholes,designs the mine pressure observation scheme of the machine roadway,waist roadway,air roadway and the 83 lower mining area transportation and pedestrian downhill roadway,and verifies and analyzes the effect of the deep hole presplitting blasting roof cutting and pressure relief roadway protection technology.There are 42 figures,16 tables and 86 references in this paper.