Research On Stability And Support Technology Of Coal Pillar Along Gob-side Roadway Of Fully Mechanized Caving Face In Extra-thick Coal Seam

With the development of mining technology,comprehensive mechanized caving coal mining has been widely used in the production of thick coal seams.Aiming at the mining of ultra-thick coal seams,how to improve the coal recovery rate and ensure the stability of the roadway during driving and working face mining has been the subject of mining research.Therefore,it is of great significance to study the width of coal pillars and roadway supporting technology of fully mechanized top coal caving face in extra-thick coal seam,which ensuring the safe and efficient production of working face.This paper focuses on this issue,taking the 61102 working face of Tangjiahui Coal Mine as the research background,using theoretical analysis,numerical calculation and on-site investigations comprehensive research methods to analyse the stability of the coal pillars and surrounding rock of the roadway,and discuss the design and optimization of the supporting scheme and parameters of the roadway along the goaf,and propose the control technology for the surrounding rock reinforcement of the roadway along the goaf was proposed.The following results have been achieved:1)Based on the key block viewpoint of the overlying rock mass structure along the gob along gob,the characteristic parameters of key block of the overlying rock mass were determined.The stability analysis model of the overlying rock mass structure was established,and the stability of the overlying rock mass structure before,during,and after mining was analyzed.2)The equilibrium equation of the coal body edge based on the limit equilibrium theory was modified,the mechanical model of the coal body at the edge of the coal pillar at the goaf side was established,and the relationship between the stress in the plastic zone at the edge of the coal pillar and the plastic zone width was derived,and reasonable formula for calculating the width of coal pillar is put forward.3)Numerical simulation method was used to simulate the stress distribution and deformation characteristics of surrounding rock of roadway under the conditions of different width coal pillar.The bearing stability of the coal pillar and the surrounding rock along the empty roadway at different stages of excavation and mining were analyzed.Affected by the variation of coal pillar width.4)Based on the engineering background,the anchoring parameters of bolts and cables are selected according to the natural equilibrium arch theory,and the supporting scheme of roadway in full-mechanized caving mining of extra-thick coal seam is designed.The deformation of roadway along the roadway is studied by using FLAC3D,and the supporting parameters are optimized.5)According to the deformation of the surrounding rock of the roadway and the stress of the anchor rod during the roadway excavation and the mining face,the rationality of the support design of the roadway and the effectiveness of the control of the surrounding rock are analyzed.Through systematic research and analysis,the designed 21m roadway coal pillar and roadway support scheme is applied to the engineering practice of the 61102 fully mechanized caving face,which improves the coal seam recovery rate and verifies the rationality of surrounding rock support design of gob side entry.Figure 40 table 5 reference 62...