Study On Stability Mechanism Of Surrounding Rock Of Roadway Side Filled With Cut Top Broken Block And Complete Technology Of Pillarless Mining

In this study,theoretical analysis,mechanical model,numerical simulation,field test and other methods are comprehensively used to study the stability mechanism of roadway side rock filled with cut top broken block,and the corresponding roadway side control scheme is proposed.The theory is successfully applied in Yangmei No.2 Coal Mine for industrial test,and the following results are obtained.Based on the study of the activity law of the overlying strata of gob side entry retaining with roadway side filling,the feasibility of roof cutting and seam forming by shaped charge blasting is analyzed through theoretical calculation and numerical simulation.The physical and mechanical models of gob side entry retaining with roof cutting and filling under different surrounding rock conditions are constructed,and then the stress characteristics of surrounding rock under different support forms and parameters are analyzed.The theoretical calculation and numerical simulation are used to study the influence of blast hole spacing,angle and depth on roof caving,vertical stress and deformation of surrounding rock in goaf,and the reasonable pre splitting parameters are determined.According to the actual geological conditions of 27101 working face in Yangmei No.2 Coal Mine,the discrete element UDEC numerical model of cutting roof and retaining roadway is established by using Moore Coulomb model;the deformation and stress evolution laws of roadway surrounding rock during driving dynamic pressure,periodic weighting,mining dynamic pressure and secondary mining dynamic pressure are studied;the influence of different support forms on deformation,stability and fracture development of roadway surrounding rock is analyzed Control effect.Mining dynamic pressure and periodic pressure are particularly critical to the control of surrounding rock.During the mining period of the upper working face,the support is strengthened 20-40 m ahead of the working face,and the stability control area 100 m behind the working face includes the lag strengthening support.According to the stress characteristics of the gangue in the side wall of the caving and filling roadway in the top cut goaf,a coupling flexible support technology composed of steel wire rope,steel mesh and diamond metal mesh is proposed to adapt to the large deformation and dynamic pressure impact of the gravel side.The combined support form of single pillar and hydraulic support combined support is determined,which is roadway support and roof and solid coal side high strength and high rigid anchor(bar)cable reinforcement support and roof cutting and filling roadway side coupling flexible support.Based on the above research results,an effective mine pressure observation scheme is proposed to measure the convergence of the two sides of the roadway,the convergence of the roof and floor,the roof separation layer,and the stress of the anchor(rod)cable.Through the analysis and induction of the obtained data,the feasibility and reliability of the above research results are tested,and the technical and economic effects are compared and analyzed to comprehensively verify the research results of this paper.