Study On The Surrounding Rock Control Technology Of "Three Soft" Coal Seam Drifting Along Gob In Zhaojiazhai Coal Mine

In this paper,12206 working face transportation roadway of Zhaojiazhai coal mine was selected as the research object.The damage characteristics and causes of surrounding rock of the“Three Soft”coal seam along the goaf,the structure of the overlying strata and the stress characteristics of the pillar,the reasonable width of the coal pillar and the related supporting technology were systematically analyzed by the methods of field investigation,laboratory test,theoretical analysis,numerical simulation and field measurement.First of all,the characteristics and causes of Transportation roadway failure of12206 working face in Zhaojiazhai coal mine were analyzed.Through the field investigation and the physical and mechanical properties test of coal and rock,the mechanical parameters of the surrounding rock were obtained.In view of the characteristics of the deformation and failure in the field,the causes of the deformation and failure of the surrounding rock were analyzed.Secondly,the roof structure and pillar mechanics model of gob side entry driving was established,and the reasonable width of coal pillar was determined through theoretical calculation.Through the proper simplification,the mechanical model of roadway roof structure and the elastic mechanics model of coal pillar were established.The structure parameters of key rock block B and the width of the limit equilibrium area in the coal pillar and the distribution of the coal pillar stress were solved.The principle of determining the width of the pillar of the roadway along the goaf was established,and the width of the pillar is determined by theory and calculation.At the same time,through numerical analysis,it revealed the stress distribution and deformation rule under different pillar width of Transportation roadway of 12206working face in Zhaojiazhai coal mine.The distribution law of lateral support pressure in goaf was studied by using FLAC^3D numerical simulation software.The stress distribution and deformation characteristics of coal pillar were studied under different coal pillar width,and the reasonable width of coal pillar was determined with the theoretical calculation results.Then,the supporting technology of transportation roadway of 12206 working face in Zhaojiazhai coal mine was put forward.The UDEC numerical simulation software was used to analyze the effect of bolt support on the stability of surrounding rock of“Three Soft”coal seam along goaf.Through theoretical calculation,the matching condition of anchor cable pre-stress was determined.The law of anchor cable pre-stress loss was analyzed by using the field monitoring data,and the anchor cable pre-stress technology was proposed,and the strengthening support of the key parts of"Three Soft"roadway along the goaf was also studied.Based on this,a high strength anchor net supporting technology for roadway driving along goaf in transportation roadway of12206 working face in Zhaojiazhai coal mine was put forward.Finally,the industrial test was carried out in the field.Through the field monitoring,the deformation of the roadway surrounding rock and the bearing performance of the bolt cable were analyzed.The results show that the surrounding rock of the roadway was effectively controlled,and good social and economic benefits had been obtained.