Application Of Catastrophe Theory In Stability Of Goaf

The problem of goaf instability has always been a hot and difficult research topic at home and abroad,but the traditional mechanical method can not explain the catastrophe and non-linearity of goaf instability and failure well,which has certain limitations.Based on the strong catastrophe and obvious non-linearity of the instability of goaf,combined with the project of "Wuping Zijin Mining Method Design" and the engineering background that Wuping Yueyang Silver Polymetallic Mine is in the stage of residual mining,the catastrophe theory is applied to study the instability of goaf,and AB is used to study the instability of goaf.AQUS numerical simulation software is used to simulate the instability of goaf.The main contents are as follows:Based on the basic mechanics theories such as material mechanics and elastic-plastic mechanics,the mechanical models of roof-pillar under different mining conditions are established,and the total potential energy of roof-pillar system under different mining conditions is calculated.With the help of catastrophe theory,the cusp catastrophe model of roof-pillar instability under different mining conditions is established.The mechanism of energy release during goaf instability under different mining conditions is analyzed,the necessary and sufficient conditions for roof pillar system instability under different mining conditions are derived,and the expressions of pillar compression and system energy release under different mining conditions are further derived.The stability of three goafs under different mining conditions is numerically simulated by using finite element software ABAQUS.The magnitude of pillar compression and the change of total energy of the system under different asymmetric coefficients are emphatically analyzed,which verifies the rationality and scientificity of the application of catastrophe theory in the study of goaf stability.Furthermore,it is further verified that the goaf under symmetrical mining conditions is more vulnerable to instability damage than the goaf under asymmetrical mining conditions.Combined with the catastrophe series method,using three catastrophe models of cusp,swallow tail and folding,several main factors affecting the stability of mined-out area are selected,and the catastrophe series evaluation model of the stability degree of mined-out area is established.The stability degree of several mined-out areas in Yueyang Silver Polymetallic Mine of Wuping is evaluated,and the evaluation results are obtained.The model provides an effective way to predict the stability of goaf reasonably.