Analysis And Research On Roof Cutting And Pressure Relief Technology In Hecaogou Coal Mine

Located in Zichang Mining Area of Triassic Coalfield in Northern Shaanxi,Hecaogou Coal Mine has the characteristics of shallow coal seam,shallow depth,thin bedrock and thick loose overlying sandy.However,the key problems of gob-side entry retaining in shallow thin seam are that the roof in caving zone is not easy to collapse and the dynamic pressure of gob-side entry appears intensely after mining.Therefore,it is of great significance to study the roof cutting pressure relief technology.Hecaogou Coal Mine was token as the research object,the relevant mechanical parameters of the roof and coal seam were given by uniaxial compression test,triaxial compression test and Brazilian splitting test.And find that the mechanical properties of the roof and coal seam surrounding rock are poor,and the surrounding rock of the roadway is easy to be destroyed.Based on the theoretical analysis of the pressure relief by roof cutting and gob-side entry retaining technology,the design of roof-cutting pressure relief were carried out,and the specific construction process,process parameters and roadway support method were determined.The FLAC3D numerical simulation experiment was carried out on technical design of pressure relief by roof cutting and gob-side entry retaining in Hecaogou Coal Mine.And experimental results shown that pressure relief by roof cutting can reduce the peak of advanced abutment pressure on roadway surrounding,and the influence range along the strike is about 40 m with 10.0 m-12.0 m between the peak and face.The practical effect of the pressure relief by roof cutting techonogy was analyzed and studied by ground pressure monitoring in face and study shown:? the pressure relief by roof cutting can reduce the peak of advanced abutment pressure and the peak in test section is lower than the one out of test section,and the peak of test section at the depth of 13.5m in coal can be reduced by 17.8%compared to the one out of test section;?the pressure relief by roof cutting can reduce the working resistance of the advanced single prop,and the peak of working resistance in test section can be reduced by 10%compared to the one out of test section;?the pressure relief by roof cutting can reduce the surface approaching displacements of roadway,and when the face is about 23m away,the displacements between roof and foot in test section can reduce by 35.80%with the displacement between roadway sides reduced by 58.12%compared to the ones out of section.?Compared with the ground pressure monitoring results inside and outside test section of the pressure relief by roof cutting,the effect of pressure relief by roof cutting is remarkable.The research results of this paper not only provide theoretical basis for non-pillar pressure relief by roof cutting in Hecaogou Coal Mine,but also provide reference for non-pillar pressure relief by roof cutting under similar mining geological conditions.