The Disturbance Law Of Coal Floor In Yongan Hetuo Coal Mine And Water Inrush Risk Division

The Hetuo coal mine is located in the middle of the Anhe coalfield.By analyzing the engineering geological and hydrogeological data of the mining area,it can be seen that the geological structure of the mining area is relatively complicated.The confined water pressure is high,the water richness is uneven,the permeability coefficient is large,and the internal structure of the mine in this mining area has damaged the integrity of the water barrier of the coal floor to a certain extent.There is a certain risk of water inrush at work.This paper collects the master geological data of the Hetuo coal mine,carefully analyzes the engineering geological and hydrogeological conditions of the mine,and uses computer software numerical simulation and vulnerability index method to study the disturbance law of the floor of the No.2 coal seam of the mine.The danger of water inrush from coal seam floor was specifically divided,and the following results have been obtained:(1)This paper uses FLAC3 D numerical simulation software and calculates by establishing relevant models to analyze the damage depth and stress change law of the coal seam floor in the direction and inclination when it advances 200 times.It is obtained that when the working face advances to 160 m,the roof failure depth after reaching the maximum,it is 62.78m;after that,the depth of the roof failure no longer changes,and the scope of damage continues to increase;when the working face is advanced to 200 m,the depth of the coal seam floor reaches the maximum,22.41 m.It can be seen that the damage caused by coal mining is limited.However,it should be noted that the mining activities of each layer will affect the integrity of the roof and floor of the coal seam,so it is necessary to pay attention to the water inrush accident caused by the damage to the coal seam during the mining process;(2)In this study,four factors were selected as the main evaluation factors for coal seam spouting: aquifer water pressure,equivalent thickness of aquifers,aquifer water richness,and permeability coefficient,and the corresponding ones were established by using GIS software.Thematic maps and normalized thematic maps,in order to complete the analysis of the impact of various factors.And by superimposing each thematic map,the water inrush danger zone map is finally obtained.Its water inrush danger level is divided into the following five levels: danger zone,more dangerous zone,transition zone,safer zone and safe zone.After comprehensive evaluation,it was found that the danger zone and the more dangerous zone are mainly distributed in the central area of the mining area.The main determinants are the large confined water pressure in the middle of the mining area and the large permeability of the rock formation,which makes it easy for the water in the aquifer to break through the bottom layer of the coal seam and enter the mine,causing water inrush accidents.