| In this thesis,the III4 gangue roadway of Luling Coal Mine is taken as the engineering research background.On the basis of field investigation and analysis,the development of joint fissures in roadway surrounding rock and the determination of physical and mechanical parameters are carried out,and the characteristics and causes of instability and deformation of roadway surrounding rock are analyzed.Theoretical analysis and numerical simulation were used to analyze the deformation and stress variation of surrounding rock in roadways with different normal distances under coal pillars.Based on the stability variation law of surrounding rock of roadway with different normal distances and the support principle of dynamic pressure roadway under coal pillar,two reinforcement schemes of surrounding rock suitable for roadway with different normal distances are proposed,and field industrial tests are carried out.(1)The crack development range of roadway surrounding rock is tested,and the crack development of roadway surrounding rock is mastered.The physical and mechanical parameters of coal and rock mass were measured by laboratory experiments.The investigation and measurement of the engineering site were carried out,and the influence range of the advance abutment pressure of the III1022 working face was determined.The deformation and failure characteristics of the roadway surrounding rock were summarized,and the main reasons for the instability and failure of the roadway surrounding rock were analyzed.(2)The influence of working face mining on the stability of surrounding rock of lateral floor roadway is analyzed.Based on the Mohr-Coulomb strength criterion,the stability analysis of the micro-units of the roadway side,shoulder and floor is carried out,and their respective failure processes are expounded.The influence of the change of normal distance under coal pillar on the stability of roadway surrounding rock is compared and analyzed by means of theoretical analysis and numerical simulation.When the working face of the floor roadway is 25 m,with the decrease of the normal distance between the roadway and the coal seam,the peak value of the vertical stress of the surrounding rock of the roadway increases,the horizontal stress of the surrounding rock of the roadway increases,the deformation degree and plastic zone area of the surrounding rock of the roadway increase,and the displacement and stress difference of the surrounding rock of the left and right sides are more obvious.(3)Based on the principle of bolt-anchor cable synergistic support,the weak parts of the anchor net support bearing structure are reinforced by the beam anchor cable,and the optimal preload value of the anchor cable is calculated by the bolt cable preload matching formula.There are a large number of cracks in the deep rock mass of the roadway roof,and the integrity of the surrounding rock of the bolt anchorage section is poor.It is proposed to use deep and shallow hole grouting to reinforce the surrounding rock of the roadway,and analyze the reinforcement effect of deep and shallow hole grouting on the broken surrounding rock of the roadway.(4)Combined with the variation law of surrounding rock stability of roadways with different normal distances under coal pillars and the causes of surrounding rock instability and failure,two surrounding rock reinforcement schemes suitable for roadways with different normal distances are proposed respectively.The numerical simulation method is used to analyze the stability of the surrounding rock of the roadway after the reinforcement of the two schemes.After the support is strengthened,the plastic zone and displacement of the surrounding rock of the roadway are reduced,and the stress and strain difference between the left and right sides are reduced.(5)The field test results show that the deformation of the surrounding rock in the reinforced section is significantly smaller than that in the unreinforced section,and the displacement of the surrounding rock in the roof and the side wall of the working face is the most obvious.Reinforcement anchor cable bearing stability,roadway surrounding rock deformation is effectively controlled.The dissertation has 57 figures,9 tables and 85 references. |
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