Failure Mechanism And Stability Control Of Surrounding Rock In Mining Roadway Under Tectonic Stress

The large deformation of the mining roadway has been one of the major problems that perplex the safe and efficient production of the coal mine.It has important theoretical and engineering significance for the study of the deformation and failure mechanism of the surrounding rock of the mining roadway and the support technology under the action of the structural stress.Based on the engineering background of Xinxin coal mine 110907 machine haulage roadway in Wantian coal industry,this paper adopts many research methods,such as field measurement,indoor experiment,theoretical analysis and numerical simulation,and starts with the distribution and evolution law of the surrounding rock stress field of the stope roadway,and discusses the failure mechanism of the surrounding rock of 110907 machine haulage roadway,the relationship between the stress field and the plastic zone and the surrounding rock deformation,and the optimization of the supporting parameters of the stope roadway The main research results are as follows:Through field sampling and measurement,it is found that the surrounding rock of 110907 machine haulage roadway is soft mudstone and sandy mudstone with low mechanical strength and poor deformation resistance.In addition,the results of mineral composition analysis show that there are high proportion of siderite,mica and kaolinite in the surrounding rock of 110907 machine lane.These minerals are easily softened and disintegrated when exposed to water and air,which can greatly reduce the strength of the surrounding rock.Based on the observation of the 110907 mechanical haulage tunnel,it is concluded that the deformation of the side of the tunnel is asymmetric,and the surrounding rock fracture of the tunnel is developed.The results of in-situ stress test show that the maximum principal stress of the roadway is 36.9mpa,the direction is 94.3 °,the dip angle is-10.2,the middle principal stress is 13.2mpa,the direction is 6.9,the dip angle is 14.1 °,the minimum principal stress is 12.1mpa,the direction is 149.7 °,the dip angle is 72.5 °,the horizontal principal stress is more than three times of the vertical principal stress,and the coal seam is obviously affected by the structural stress.The stress,plastic zone and displacement of the 110907 machine haulage roadway in Xinxin coal mine are simulated by using the finite element simulation software FLAC3 D.It is found that when the working face is pushed forward,the strata will move,the self weight stress of the rock above the goaf will transfer to the rock around the goaf,and the stress field will be redistributed.The disturbance intensity of the mining face is large and the scope is wide.The release of mining stress to the goaf will cause the rapid increase of the plastic area of the roadway,which will cause the plastic area to enter the malignant expansion stage from the slow expansion stage.The displacement of the surrounding rock is highly consistent with the expansion trend of the shape of the plastic zone of the surrounding rock.The plastic zone of the surrounding rock in the direction of small displacement of the surrounding rock is also smaller,and the plastic zone of the surrounding rock in the direction of large displacement is also larger.Finally,based on the control principle of surrounding rock stability of mining roadway under the action of structural stress,combined with the field conditions of 110907 roadway,it is found that the "hard shoulder" with high strength and high rigidity supporting structure can not achieve the ideal supporting effect.Therefore,adopting the support concept of "combination of let and resist" and the way of reserving a given deformation for the roadway,a comprehensive support mode of "bolt,steel mesh,shotcrete,ordinary anchor cable,high-strength hollow grouting anchor cable" is proposed.The numerical simulation results show that the optimized support scheme can effectively control the concentrated stress of the surrounding rock,greatly reduce the scope of the plastic zone,improve the integrity of the surrounding rock,and achieve the expected control effect.