Research On The Mechanism And Prevention And Control Of Coal Column Induced Active Load Ore In Room Collection

Due to the disorderly mining of the small coal kiln,a large number of room-pillar goafs have been formed in the coal seams that are relatively shallow from the surface.The irregular coal pillars left over from the goaf have greatly affected the mining of the lower coal seams.The energy accumulation near these remaining coal pillars is prone to form stress concentrations.During the mining process of the lower coal seam working face,the stress field of the surrounding rock of the stope is liable to change.When the working face is advanced to a certain position,the coal pillar in the housing mining area suddenly breaks down,the roof supported by the coal pillar collapses in a large area,and a dynamic load pressure is formed on the working face of the lower coal seam,causing a roof accident on the working face of the lower coal seam.Therefore,this article takes the mining of the 12402 fully mechanized working face under the room-pillar goaf in Shijietai Coal Mine as the background.It affects the stability of the coal pillar in the mining area under the influence of mining in the lower coal seam,and the surrounding rock is affected during the process of entering and exiting the coal pillar.Force,coal pillar failure and deformation state are analyzed,and the following conclusions are mainly drawn:1.According to the theory of elasticity and catastrophe,the calculation formula of the width of the elastic zone necessary for the stability of the coal pillar is obtained,and it is used as the basis for judging whether the coal pillar is unstable or unstable.After calculation,it is found that during the mining process of the 12402 working face,the residual coal pillars in some mining houses will undergo instability and damage,which will cause other domes in the mining area to have a domino instability effect.2.When the 12402 working face is located below the coal pillar and the coal pillar is in and out,the coal pillar and roof failure in the mining area are analyzed,and the stress characteristics of the roof when the working face is at different positions relative to the coal pillar are analyzed,and the inlet and outlet are explained.Coal pillars are susceptible to the accident caused by dynamic loading and pressure.3.Using numerical simulation experiments,it is concluded that the coal body in front of the coal wall and the roof and coal pillars of the working face are subject to shear stress during the entry and exit of the coal face.Under the conditions of shallow burial depth,the top-cut phenomenon is easy to occur.Especially in the coal pillar stage,the coal pillar in the house has plastic failure as a whole.With the destruction of the remaining coal pillars in the goaf,the roof of the working face will be cut along the coal wall,which will cause dynamic load impact on the working face.According to the results of the above research,measures were taken to control the coal pillars of the house by using pre-split blasting in advance.The feasibility of the pressure relief of the coal pillar blasting roof was demonstrated.The pressure relief parameters and organization scheme of the coal pillar blasting roof were determined.The test proves that the pre-split blasting concentrated coal pillar has a significant effect on roof control and disaster prevention,and has certain guiding significance for the safe mining of the lower working face in the housing mining area.