Study On Mechanism And Control Technology Of Slope Instability Caused By Underground Mining

In this paper,in order to solve the problem of slope instability caused by underground mining,through theoretical analysis and numerical simulation,the instability mechanism and control technology of mining slope are studied systematically.Firstly,according to the influence of different geological conditions and mining activities on slope stability,the types of mining slope,the instability modes and instability types of mining slope are summarized.Based on the stress-strain state of slope before and after mining,the displacement characteristics caused by mining,the relationship between underground mining and slope sliding structure,and the influence of rainfall on slope stability,the general instability mechanism of mining slope is analyzed;On this basis,the instability laws of different types of mining slope are studied,and FLAC3D numerical simulation is used to reproduce the instability deformation process of different types of mining slope.Research shows:for the mining slopes with different slope angle,the greater the slope angle,the worse the stability affected by mining;for mining slopes with different slope shapes,the overall stability of concave slope is better than convex slope under the influence of mining.Based on the above study,taking concave slope as an example,the instability process and characteristics of mining slope under different instability modes are studied,including five instability modes,reverse slope mining,along slope mining,strike mining,upward mining and downward mining.Based on the principle of FLAC3D strength reduction method,the safety factor of slope under different instability modes is calculated.Research shows:in different working face advance directions,the reverse slope mining has the least influence on the stability of slope,followed by the along slope mining,and the strike mining is the most unfavorable to the stability of slope;on the basis of reverse slope advancing,in different coal seam inclinations,the upward mining is more likely to cause slope instability than the downward mining.Finally,The type,instability mode and failure characteristics of mining slope in specific research area are analyzed,the underground and surface control measures for the stability control of mining slope are listed.Starting from the main causes of the instability of the mining slope,the underground control measures for the mining slope filled with the goaf at the slope toe while adopting the reverse slope mining are proposed.Through the comparative analysis of the displacement,stress,plastic zone and safety factor of the mining slope before and after the control measures are taken,it is concluded that the control measures have significant effect on the stability control of the mining slope.The research results of this paper are of great significance for guiding the safe mining and mining slope control under the slope,and can provide certain reference value for the engineering under the same geological conditions.