The Structure And Control Of Roof And Rock Coal In Passing The Roadway(Group)in Re-mining Face

Recycling the high quality resources left in the mined-out area and realizing the re-use of the old mining residue is of great significance to China's economic development and sustainable utilization of resources.Based on the geological background and the geophysical means of Shenghua Coal Mine,this paper analyzes the occurrence of coal seam in this paper,and analyzes the occurrence of coal seam,The top plate mechanics model of the two boundary conditions under different boundary conditions is calculated and the roof form is calculated and simulated.Through the numerical simulation method,the form and the law of the roof collapse and the two kinds of conditions are analyzed,and the stress distribution and the shaping area change of the remaining coal pillar with the working face are analyzed.Aiming at the large pressure of the support face of the mining face in the key block B,the paper puts forward the technical method of advanced grouting and filling technology,and the grouting parameters are optimized.Its main work is as follows:(1)The depth of the reserved lane is mainly 2 ~ 10 m and the width of the remaining coal pillar is 4 ~ 20 m by means of geophysical method.The coal seam is divided into five cases,namely,the state of solid coal,,There is empty state,direct top good,top coal caving state,bottom coal,top coal all mining,direct top good state,direct top of the state.(2)The based thickness of the No.3 coal is 4.66 m and the direct top thickness is 16.10 m.According to the theory of elastic thin plate,it is proved that the possibility of taking Shenhua coal directly as the elastic sheet is provided,which provides a theoretical basis for the following analysis.(3)The mechanical model of "coal pillar + roof" system under the condition of mined-out area is constructed.The formula of the center deflection of the roof is calculated,and the maximum deflection of the roof is 3cm under the condition of "pillar + roof" system The amount of sediment is small and the whole area is stable.(4)The model of roof boundary condition change in the process of initial collapse and cycle collapse in the face of the mining area is constructed.The roof boundary condition is fixed from the four sides to the two sides of the initial collapse.The collapse of the roof can be considered as a simple and vertical "O-X" type of fracture;the cycle of the collapse of the roof can be seen from the side of the simple side of the three sides of the support,to the side of the simple three-sided The shape of the roof fracture is asymmetrical vertical "semi X-O" type of fracture.Compared with the recovered solid coal,theexistence of the remaining coal pillars and the empty lanes causes the vertical cracks in the middle of the roof to appear on the side of the deviation.(5)Through the numerical simulation of FLAC3 D two different lane width along with the face to promote the role of the remaining coal pillars and roof are compared.As the following conclusions: When the width of the alley is large,the area of the coal pillar is changed rapidly,resulting in the vertical stress of the coal pillar and the superposition value of the advance pressure of the working face,and the acceleration of the stress is accelerated in the process of advancing the working surface,Especially after exposing the empty lane,the vertical stress changes strongly,the phenomenon of premature coal pillar instability;The change of the width of the lane causes the difference between the length of the key block B and the length of the key block C,and the positive correlation is that the vertical crack in the roof is always biased towards the rear of the goaf.(6)The mechanics model of "key block B" is established based on the condition of over-the long lane.And the working resistance of the stent is obviously higher than the rated working resistance of the bracket 3.In order to be able to smooth the work area,it is proposed to adopt the advanced grouting filling technology for the empty alley or the caving zone.The thickness of the bearing layer is 4.5m,the thickness of the cutting layer is 2m,the strength requirement of the bearing layer is 2MPa,and the strength requirement of the cutting layer is 1.5MPa.At the same time,the parameters such as grouting pressure,grouting volume and drilling angle were optimized.