Principle And Application Of Cutting Roof And Retaining Roadway By Blasting Drilling In21602 Transportation Roadway Of Binhu Coal Mine

Under certain conditions such as coal seam thickness,burial depth and overburden combination structure,the gob side entry with roof cutting has technical advantages in improving coal resource recovery and relieving mining and excavation continuity,which has been widely promoted and applied in China in recent years.Binhu Coal Mine mainly mines 16#coal seam with an average thickness of 1.35m.Its direct roof is hard limestone with a Proctor coefficient greater than 8 and an average thickness of 4.6m.In order to improve the recovery rate of 16#coal seam,taking the transport roadway of 21602 working face as the engineering background,using laboratory tests,theoretical analysis,numerical simulation and industrial application and other research methods,the blasting roof cutting The key technical parameters such as stability control of roadway surrounding rock have been successfully applied in the field.The laboratory tested the physical and mechanical property parameters of the roof rock of 21602 working face,mastered its strength and deformation characteristics,and provided basic parameters for the subsequent numerical simulation of the stress and deformation of the surrounding rock of the roadway;Theoretically analyzed four mechanical models of roadway roof strata in different roadway retaining stages,including fixed support at both ends and fixed support at one end and simple support at one end of roadway roof in the slit area,cantilever beam of roadway roof in the dynamic pressure area behind the working face frame and simple support at one end and fixed support at one end in the pressure stabilization area,and proposed support countermeasures for four different mechanical models;The FLAC^3Dnumerical simulation software was used to study the characteristics of stress and deformation failure of surrounding rock at different stages of roadway retaining,and then the depth and angle of blasting top cutting drilling were determined;The industrial test shows that the cracks at the bottom of the blasting top cutting hole have been cut through,and many longitudinal cracks have emerged in the middle of the hole after blasting.During roof cutting and roadway retaining,the surrounding rock deformation of the roadway has been effectively controlled,meeting the requirements of mine safety production.The successful practice of blasting top cutting and gob side entry retaining technology in the transport roadway of 21602 working face provides a useful reference for the popularization and application of this technology under similar mining conditions.