Study On The Gob-Side Retaining Wall Of Pillar-Free Mining Technology With Great Mining Height In Sijiazhuang Coal Mine

Based on the mining conditions of 15117 coal face in Sijiazhuang mine,the problem of no pillar mining is solved by using the technology of retaining wall along the goaf,and from the point of view of theoretical analysis,analyses the factors influencing the stress and stability of the inner wall of the roadway under the action of overburden suspension roof in the goaf.Through numerical analysis,the method of controlling variables is adopted to further determine the factors influencing gob-side retaining.The main factors of wall stability,reasonable wall filling materials and technology and equipment were selected,and good effect of retaining wall along the goaf was achieved in field practice.The following specific research work has been carried out in this paper:(1)The problem of no pillar mining is solved by using the technology of retaining wall along the goaf,that is,concrete wall is poured along the solid coal side of adjacent coal face in mining roadway while mining at present,which provides conditions for the rapid implementation of gob-side roadway driving in adjacent coal faces.(2)The stability of the retaining wall along the goaf is studied,and the stress expression of wall force under the action of suspended roof in goaf is obtained.The results show that the length of suspended roof in goaf,the supporting performance of gangue,the bearing characteristic of solid coal and the mining height of coal seam are all important factors affecting the stability of the wall in the roadway.(3)The sensitive factors that affect the stress and deformation of the retaining wall were analyzed,and obtains that the location of the roof fracture in the goaf is also the key factor that affects the bearing capacity of the wall,then design the reasonable filling parameters,and obtain the good effect of retaining wall.This paper has 38 figures,5 tables and 87 references.