Numerical Simulation Of Mining Effect On The Bottom Plate Hidden Collapse Column Activated Water Conducting Mechanism

In the process of coal mine production,the collapse column seriously affects the layout of the mining area and the working face,reducing the coal mining rate,reducing the service life of the mine,and threatening the safe production of the mine.In all mine accidents,the economic loss caused by the collapse column is the greatest.Therefore,it is of great significance to study the development characteristics of the collapse column and the mechanism of water-inrush of the collapse column to improve the safety of mine production,rationally arrange the mining area and working face,and improve the coal mining rate.This paper mainly studies the water inrush situation of the concealed collapse column in the floor.The main work and conclusions are as follows.(1)Combining with the relevant mechanics knowledge to analyze the stress distribution of the column and the surrounding of the column,and to analyze the stress distribution formula under the condition of self-weight,top pressure,side confining pressiure and groundwater pressure,and the criterion of the activated water diversion of the collapse column is derived.Based on the analysis of the activated water diversion of the subsurface collapse column,the infiltration width of the surrounding rock,the width of the surrounding plastic damage,the depth of the excavation failure of the roadway floor are calculated,and the water inrush criterion is give.(2)In this paper,FLAC3D numerical simulation software is used to analyze the influence of different lithologic combination conditions on the activated water inrush of the strata.The FLAC3D numerical simulation software is also used to analyze the influence of the position of the concealed collapse column on the activated water inrush of the collapse column.The simulations show that the water separation of"soft,hard,soft hard"and "hard,soft,hard,soft" combinations are the best,and the water separation of "soft,hard,hard,soft" and "hard,soft,soft hard" combinations are the second.The water separation of "soft,soft,hard,hard" and "hard,hard,soft,soft"combinations are the worst.Under the same conditions the concealed collapse column on the side of the working face is less affected by the mining operation than which at the center of the working surface.(3)Through the lithology analysis of the rock strata from the bottom plate to the top of the collapse column of the 31120E working face containing the hidden collapse column of the bottom plate,it is found that the combination type between the two is "hard,soft" type,which is the most likely type of water inrush.The mining condition of the working face was simulated,and it was found that when the mining was pushed to the position 10m from the axis of the collapse column,the collapse column might have an activated water inrush.(4)The measures to prevent water inrush of collapse column are studied.In addition,the 31120E working face was specifically governed and the governance effect was monitored.