Study On Mining Effect Of Mechanical Behavior Of Surrounding Rock Under The Condition Of Difference Between Stope Buried Depth And Space Span

In the field of mining research and development engineering in China,the mining of metal mines is often restricted by geological and mining conditions,and there will be great differences in the buried depth distribution and spatial structure of goaf.Different buried depth distribution and span differences will have different effects on the stress effect of surrounding rock and endanger the production safety of mines,Therefore,it is of great engineering value to analyze the stability of stope surrounding rock during excavation under the conditions of different buried depth and empty span.Based on the north high stage stope project of 20 joint roadway in an iron mine in East China,through theoretical analysis,numerical test and other means,this paper studies the stress redistribution mechanism and spatial displacement deformation law of surrounding rock in goaf during stope excavation under the conditions of different buried depth and empty span,and obtains the following main research results:(1)Using a variety of mechanical theoretical analysis methods,the stope roof is simplified,and the theoretical calculation formula of stope limit span is obtained.Through the integration of the stress and deformation theory related to the stress of the surrounding rock of the stope and the previous research results,the roof structure of the stope is simplified.Under the influence of the force on the roof,the roof stress mode of the surrounding rock of the stope is analyzed.(2)The mechanical model of stope surrounding rock is established by combining mathematical and mechanical methods,and the stress component expression of stope surrounding rock is established and solved.The establishment of mechanical model is one of the key steps to explore the stability of stope.In this paper,the stope engineering in the north of 20 combined roadway in an iron mine in East China is simplified,and the mechanical model of stope surrounding rock is established.The stress analysis of the stope is carried out by using the theoretical analysis method of elasticity,the relationship between the force and displacement of the surrounding rock mass of the deep buried stope is studied,and the relationship between each component and the horizontal and vertical parameters is explored,which provides a solid theoretical basis for the numerical simulation test of engineering scale.(3)Taking eight indexes such as stress,displacement,failure zone and plastic zone as the evaluation factors of surrounding rock stability,the stability law of stope surrounding rock during the excavation of stope under the condition of empty span difference and different buried depth is explored.On the basis of the above research results,the numerical simulation test was carried out on the high-level stope project north of the 20 th lane in an iron mine in East China.The results show that the stope span has a decisive influence on the stability of surrounding rock under the condition of 450 m buried depth,and 18 m is suitable for the stope span;Under the same span and different buried depths,the change of buried depth also has a certain influence on the stability of surrounding rock,and the change of stress has a certain linear proportional relationship with the buried depth.