The Research And Application Of The Special Thick Coal Seam Support Forms Along Gob Roadway In Tashan Mine

In order to study the support parameters of gob-side entry driving in extra-thick seam,this paper takes the coal pillar changing section of 5204-2roadway in 8204-2 working face of Tashan mine as the engineering background,and combines the methods of theoretical calculation,numerical simulation,field test and effect test,etc.,based on the study of the failure mechanism of the surrounding rock of the roadway,the distribution curve of the lateral supporting stress and the width of the plastic zone in the adjacent GOAF are derived,this paper analyzes the influence of lateral support pressure on roadway support under the condition of different coal pillar widths,and calculates the curve distribution of support stress along working face strike,in order to determine the best time period for monitoring the effectiveness of roadway support,the area and peak value area of roadway support affected by mining face are Quantitative analysis On the basis of theoretical research results and measured tunnel geomechanical parameters,the most reasonable support form and strength of the tunnel are calculated by numerical simulation method,finally,a roadway support form which accords with the actual conditions of 5204-2 roadway is designed,and various ground pressure observation methods such as surface displacement of roadway,deep displacement of surrounding rock,stress monitoring of support and roof abscission layer observation are adopted,in order to verify the science and rationality of roadway support design,the deformation and support failure of roadway surrounding rock were observed and analyzed.Based on the theoretical analysis and experimental results,the following conclusions are drawn:(1)the distribution of the stress field of the surrounding rock is the main factor affecting the support effect during the gob-side entry driving in extra-thick seam,the main aim of roadway support design is to control the deformation of roadway under different surrounding rock characteristics.(2)under the condition of different coal pillar widths,the stress of roadway driving along Goaf is greatly influenced by the stress field,and the design of coal pillar widths should try to satisfy the stress distribution law,the effectiveness of roadway support can be protected more effectively in the area of stress reduction.(3)under the condition of two-way stress superimposition,the strata pressure of roadway is much larger than that of one-way stress,and the displacement of Roadway surface is obviously larger than that during excavation,it is very necessary to reinforce the support with anchor cable.(4)under the condition of the same supporting form and strength,the side deformation of the real coal body in the roadway is larger than that of the coal pillar,and the deformation of the two sides is larger than that of the roof.According to the actual width of coal pillar,the support strength in the area with large deformation can be properly strengthened.(5)the designed support form and strength have strong adaptability to the gob-side entry driving in the extra-thick coal seam with the width of coal pillar ranging from 6m to 30 m,but when the width of coal pillar is from 30 m to 50 m,the current support form and strength,especially the roof support of roadway,under the condition of superimposed stress of advance support,the roadway support is invalid,the surrounding rock is destroyed seriously,and the support requirement of safe production can not be met without other decompression measures.The research results can be used as a reference for roadway design in the later stage of Tashan coal mine under the condition of various coal pillar widths.