Stady On The Mechanism Of Mutation Instability And The Stability Of Large Goaf In Gypsum Mine

As the gypsum mine is more backward mining technology and mining time earlier,a lot of gypsum ore retained a large number of mined areas,the history of many times by the gobatic instability caused by major production safety accidents,a serious threat to people's lives and property safety.Systematically studying the stability of the gypsum ore pillar and roof,the mechanism of the chain-type instability reaction in the goaf and the stability of the large-area suspension roof by using field research,laboratory test,theoretical analysis and numerical calculation.The results are as follows:(1)The gypsum rock mass in gypsum mine goaf was studied by means of experimental method.The uniaxial compressive strength,uniaxial tensile strength and shear strength of gypsum rock mass were tested by electronic universal testing machine.(2)Obtained the damage constitutive equation of gypsum rock mass by establishing the shape evolution parameter of gypsum rock mass on the basis of considering the failure characteristics of surrounding rock.Based on the catastrophe theory and the damage constitutive equation of the gypsum rock mass,the cusp catastrophe equation of the pillar is deduced,and the instability criterion of the pillar is obtained.Based on the analysis of the deformation and failure characteristics of the roof and the pillar and the thin plate theory,the mechanical model of the roof and the pillar is established to reveal the failure law of the pill in the gypsum mine.(3)According to the relationship between the pillar load and the strength of the pillar,the safety factor of the pillar is calculated,and the dynamic calculation method of the zombing reaction in the goaf is put forward.The mechanical model of the pallets with large area suspended in the goaf is established,and the stress distribution of the large area suspended roof in the goaf area is revealed.(4)The typical area is simulated by Flac3 D based on the geological characteristics of the SuBei gypsum deposit which's geological form of the goaf and the roadway is classified.The large-scale suspension roof formed by the failure of the pillar and the pillar is calculated by using dynamic calculation method.The results show that the numerical calculation is basically the same as the simulation results.