Research On Stability Control Of Surrounding Rock In Tunnels With Weak Interlayers In Jinfeng Gold Min

The existence of weak interlayer will significantly affect the stability of roadway surrounding rock.With Jinfeng Gold Mine as the engineering background,this paper adopts Comprehensive use of a variety of research methods.The distortion and failure features of deep roadway with weak interlayer are summarized,the main control factors impacting the distortion and failure of such roadway are analyzed.On this basis,the optimal support pattern is put forward.The principal conclusions are indicated as below:(1)Through on-the-spot inquiry of the underground roadway,it is found that the surrounding rock of the orebody in the study area is mainly composed of sandstone interbedded with mudstone.The rock mass quality is poor,the roadway stability is poor,and the surrounding rock structural plane is developed and concentrated.The surrounding rock deformation of roadway generally has the following characteristics: the two sides of roadway have large deformation,roof collapse and floor heave occur asymmetric deformation and failure.(2)Through theoretical analysis,it is obtained that the main controlling factors affecting the stability of surrounding rock of roadway with weak interlayer are as follows: buried depth of roadway,dip Angle of soft interlayer,position of soft interlayer in roof.An improved model for the stability evaluation of roadway surrounding rock with weak interlayers was established,and the stability evaluation of the study area was carried out,and it was found that the stability of the roadway was unstable.The evaluation results of the model were consistent with the reality,which indicated that the model had good adaptability in engineering application.(3)The influence of dip Angle and position of weak sandwich on the deformation and failure of the model is studied by means of physical test.When the dip Angle of the weak interlayer is not0,the asymmetric deformation and failure of the model occur.As the dip Angle of soft interlayer increases,the main strain concentration area of the model increases.As the position of soft interlayer gradually moves away from the tunnel head,the main strain concentration area of the model decreases.(4)Through the approach of numerical simulation,the influence of different roadway buried depth,weak interlayer dip angle and position on the stability of roadway working face is studied.With the increase of tunnel depth,the deformation and failure of surrounding rock become more and more serious.With the increase of the dip Angle of soft sandwich,the Mises stress value increased first and then decreased,but the stress concentration range increased gradually,and the deformation and plastic zone volume of the surrounding rock increased constantly.With the increase of the distance between the soft sandwich and the roof,the Mises stress and plastic zone decreased,and the Mises surface displacement decreased gradually.(5)On the basis of the previous research,using the supporting principle of large strength and small weakness,the optimization scheme of composite support is proposed pertinently.Numerical simulation and industrial test are applyed to prove the credibility of the support technology.The research results can provide some reference for resembled roadway engineering support.