Mining Pressure Law And Coal Pillar Size Optimization For The Top Coal Caving Face Of A Coal Mine

It is easy to occur the mining pressure problems such as roof breakage,support crushing,roadway deformation and so on,which are caused by roof crushing and roof breaking in advance,due to the overlying strata in fully mechanized caving mining of thick coal seam have a large activity space and a strong mining pressure.In this paper,the fully mechanized caving face of ZF201 thick coal seam in the A coal mine is the research object.The law of surface pressure is studied by means of field measurement and theoretical research.A numerical model was established to calculate the influence range of goaf roof movement,the vertical stress distribution and the horizontal displacement of roadway pillar,and the reasonable size of section pillar was analyzed according to the results.Finally came to the following conclusion.(1)Face caving down with the collapse of the basic goaf can be filled.Because the mining space is high,the working face pressure is obvious in the caving process.(2)In the early stage of the working face,the average period pressure distance of the old roof is 13.4m.As the speed of the working face is accelerated,the period pressure distance is increased to an average of 18 m.The average period pressure distance of the whole working face is 15.7m.(3)The working resistance distribution of the working face support is basically normal along the working face direction,and most of the supports are in good working condition.The working face should try to improve the initial support of the support as much as possible.The actual measurement shows that the selection of ZF10000/18/33 hydraulic support on ZF201 working face is reasonable and can adapt to the conditions of coal seam and roof on site.(4)Combined with the bolt stress,surrounding rock stress and roof separation observation of the two roadways on the working face,the influence range of the leading abutment pressure on the working face is about 101 m in front of the working face.The obvious influence range of advanced abutment pressure is about 53.8m from the working face to its front,and the severe influence range is about 30.6m from the working face to its front.(5)The influence range of inclined plastic deformation in the goaf of the working face is 7m,and the distribution range of peak stress is beyond 7m.The horizontal displacement and plastic deformation of pillar side in roadway are larger when pillar size is less than 7m,and tend to be flat when pillar size is greater than 7m.The numerical calculation optimization result of coal pillar size along the roadway is 7m.This paper consists of 30 pictures,17 tables,and 96 references.