Bearing Characteristics Of Coal Body In The Roadway Driving Along Goaf In Sijiazhuang Mine And Asymmetric Control Technology

This study comprehensively uses theoretical analysis,laboratory experiments,numerical simulations,field tests and other methods to study the causes of large deformation of the coal body along the excavation of the Shijiazhuang Mine,and proposes corresponding control technology.The results were successfully carried out in the industrial test of Huifeng Lane,15106 working face of Sijiazhuang Mine.The study mainly achieved the following conclusions:According to the theory of elastic-plastic boundary treatment and the theory of maximum bending moment,the breaking position of the lateral basic roof along the goaf is calculated respectively.The breaking position of the basic roof is 4.5m away from the goaf side,12-15 m away from the goaf side and 12-15 m above the roadway or solid coal body.Through UDEC numerical simulation software,the stability of roadway side coal mass with three different fracture locations is analyzed,and the deformation characteristics of roadway side coal mass with three fracture locations are analyzed.Combining with the field situation,it is considered that the main reason for the large deformation of the solid coal side in Sijiazhuang Mine is that the basic roof fracture is located in the solid coal side.The change of basic top bending moment under different influencing factors is analyzed.The UDEC numerical simulation is used to analyze the support pressure,maximum principal stress cloud distribution and variation of coal pillar and solid coal after roadway excavation.When the basic top fracture position is above the real coal body,the high stress extrusion zone caused by the overlying key block on the solid coal is the main cause of the large deformation of the solid coal,and the peak of the support pressure is transferred to the inner side of the solid coal.And always exist.Drill holes arranged in the roadway to pry into the top plate breaking condition.And put forward the corresponding physical coal control ideas,and finally choose to strengthen the solid coal body support strength to control the large deformation of the real coal body.According to the corresponding control ideas,the bolt,anchor cable +W steel strip + steel ladder beam + metal mesh joint support form is proposed,and relevant support parameters are determined through numerical simulation and borehole peeping,and the original support scheme of the mine is carried out.In contrast,verify the feasibility of the support program.