Research On Deformation And Failure Mechanism Of Deep Soft Rock Roadway And Support In Mujiazhuang Coal Mine

With the continuous increase of coal mining depth,deep mining has gradually become a common mining mode.According to the conditions of deep mining,it is necessary to use corresponding support means to control the deformation of the surrounding rock of the roadway.In a large number of deep mines,the surrounding rock is mainly composed of engineering soft rock,which poses a challenge to how to effectively carry out support work.Under the conditions of deep soft rock,the surrounding rock deformation of the roadway is very serious,and the bottom heave is serious,which threatens the safety of production and life in underground coal mines.Aiming at this kind of roadway surrounding rock deformation,this thesis takes the No.5 coal downhill roadway support in Mujiazhuang Coal Mine as the engineering background,and studies the deformation mechanism of deep soft rock roadways in coal mines through theoretical analysis,numerical simulation,and on-site engineering tests;After summarizing various influencing factors,using numerical simulation methods,reasonable support methods that meet the engineering conditions are analyzed,and field applications are carried out.The main research results are as follows:(1)By establishing an ideal mechanical model for the deformation of the surrounding rock of the roadway,the law and characteristics of the deformation of the surrounding rock of the roadway are analyzed,and the expressions of the radius and displacement of the plastic zone of the surrounding rock of the roadway are obtained.(2)Research on the deformation mechanism of the surrounding rock of the roadway found that:as the buried depth of the roadway increases,the distribution range of the plastic zone of the surrounding rock of the roadway will also expand and the displacement will increase;while the nature of the surrounding rock of the roadway,the internal friction angle has an effect on the plasticity of the surrounding rock of the roadway.Zone changes have little effect.Relatively,cohesion can positively affect the stability of the surrounding rock mass;the faults distributed near the surrounding rock change the stress environment of the roadway and cause the roadway instability;the pressure generated by the groundwater will also promote the surrounding rock mass.The appearance of cracks,causing deformation and failure(3)Use FLAC^3Dsoftware to establish a three-dimensional model of the No.5 coal downhill roadway in Mujiazhuang Coal Mine.According to the model,the plastic displacement,stress distribution and changes in the distribution of plastic zone during the deformation process of the roadway are studied,and the new design is passed The new roadway support scheme with the addition of anchor cables to control the surrounding rock of the roadway is verified with the roadway model.It is found that the new scheme can effectively control the deformation of the roadway surrounding rock and reduce the displacement and deformation speed of the roadway surrounding rock deformation.(4)In the test section of the newly excavated roadway of the No.5 coal downhill roadway in Mujiazhuang Coal Mine,the new support scheme was verified on site.After180 days of observation,the results showed that the ground heave of the roadway surrounding rock decreased from about 500 mm to below 240 mm,the approaching amount of the roof and floor drops from nearly 1000 mm to about 450 mm,that is,the deformation of the surrounding rock of the roadway has been effectively controlled.