Study On Empty-support Roof's Self-stabilization Regulation For Fast Driving Coal Roadway And Optimization Of Construction Scheme

Rapid drivage of coal roadway is an important supporting technology for improving the speed of single excavation,resolving the contradiction of mining and promoting the mechanization of coal mine.Its technical essence is to solve the problem of allocation between three major processes of breaking rock,supporting and loading in the optimized empty roof,edge or interior,and optimizing the tunneling technology.Scientific and reasonable empty-support distance is the prerequisite for safe and rapid excavation.At the same time,the support technology optimization is the core to improve the single excavation because the support approximately occupies 70% of the roadway excavation time.In this thesis,Jining No.3 Coal Mine 183?05 working face haulage entry as the engineering background.Using the method of theoretical analysis,numerical calculation and industrial test combination,with empty top roof plate theory as the breakthrough point,analyzes the layered rectangular tunnel roof area sheet model's mechanical behavior,revealing the empty-support area roof's stability evolution law under rapid excavation,and clarifies the stress environment on the impact from the characteristics of maximum empty-support distance.Finally,on the basis of the optimization of roadway support density,the optimization of tunneling construction technology is carried out by using multi process cross parallel method based on the principle of minimizing working time.The following conclusions are obtained:(1)Established four clamped edges of head plate roof mechanical model.Using the theory of elasticity on the sheet model are analyzed,derived and calculated the deflection model and stress distribution of the theoretical formula,and the tensile failure criterion was obtained from the theoretical formula of empty top limit.(2)Using FLAC3 D software to study the influence of the empty-support distance on the stress,displacement and plastic distribution characteristics of the empty-support area,the support area and the front of the head.The results show that the roof spacing has little influence on the stability of the surrounding rock of the supporting area and the front of the tunnel,and has a significant influence on the stability of the surrounding rock of the roadway in the supporting area.(3)The influence of the stress environment on the ultimate void spacing is simulated.Different depth and lateral pressure coefficient,empty top zone deformation law of surrounding rock with the same distance support end row distance increasing,roof subsidence,floor closer and closer to the left side volume increased firstly and then decreases,the maximum distance between the supporting end row 3~4m;when the tunnel buried depth more than 600 m and 1~2 in the lateral pressure coefficient,deformation of surrounding rock increases obviously.(4)By means of theoretical analysis,numerical simulation and field measurement,the original construction scheme of Jining No.3 Coal Mine was optimized.The average speed of excavation is increased from 6m/d to 9m/d,and good results have been achieved.