Study On Stability Of Gently Inclined Floor Rock Formation Based On Catastrophe Theory

There are many types of coal in China,the proportion of near-level and gently inclined coal seam is 85.96%,and the inclined coal seam is 10.16%,the steeply inclined coal seam is 3.88%.In the existing research,people pay more attention to the problem of horizontal deformation of the horizontal floor,and less research on the equilibrium stability state of the gently inclined floor rock after breaking.Therefore,the stability analysis of the slow-sloping floor rock formation after breaking is an indispensable research content in the stability of coal mine roadway floor.In this paper,based on the occurrence characteristics and fracture characteristics of the gently inclined floor rock,the initial post-buckling theory and the catastrophe theory are used to investigate the instability and breaking mechanism of the gently inclined floor rock and the buckling behavior after the bifurcation,and the fracture of the gently inclined floor rock is determined.After the amplitude of the ridge displacement and the relative displacement of the two ends,the relationship between the displacement amplitude of the floor rock and the relative displacement of the two gangs is given,and the curves of the relative displacement and displacement amplitude with the inclination of the rock are obtained.The Lagrange median value theorem is used to determine the breaking position of the floor swell,and the breaking position of the gently inclined floor rock and the relative displacement after breaking are analyzed.The paper also analyzes the equilibrium configuration and equilibrium path of the gently inclined floor rock at the bifurcation point and the influence of other related factors on th,e stability.The accuracy of the relative displacement and displacement amplitude analysis results is verified by an example.Based on the theoretical study of the stability of the gently inclined floor rock,the stability evaluation system of the floor rock layer is established,including internal factors and principal component analysis method is proposed to construct the comprehensive evaluation model of rock formation stability of gently inclined floor Taking 10 coal mine roadway floors as samples and using SPSS software,two principal methods of principal component analysis and correlation analysis are used to determine the importance ranking of the same system indicators and the correlation between the indicators,using the normalization formula and the correlation of the same system index to calculate the catastrophe level value,and the total mutation membership function value is obtained through layer-by-layer hierarchical calculation.With reference to the national mine geological regulations,combined with the geological data of the coal mine,the stability of the coal seam floor is divided into five levels:extremely stable,stable,moderately stable,unstable and extremely unstable.The evaluation results of the stability of the gently inclined floor rock layer are verified,and the results show that the evaluation system is effective.