Study on New Type of Roadway Side Support Technology in Coal Mines

In order to solve the problems of coal pillar loss and relieve the tension of mining replacement in the coalface of a coal mine, this study proposes an adaptive method of retaining roadway along gob with supporting body (pier column) near loading roadway. The supporting technology of pier column retaining roadway along gob is studied through theoretical analysis and numerical simulation. The results show that the roof activity of roadway along gob can be divided into three distinct stages, namely, the stage influenced by primary mining, the stability stage of roadway retention, and the stage influenced by secondary mining. By establishing a roof mechanics model, equations are derived for calculating roof cutting resistance in three stages of gob retaining roadway, and the parameters of the supporting pier are determined. Combined with FLAC 3D numerical simulation, this study develops a numerical model to investigate the surrounding rock stress distribution characteristics and deformation rules, as well as the stress and deformation rules of piers and pillars during the two mining periods of gob retaining roadway. The numerical results demonstrate that the compressible pier column supporting body adopted in this study can not only achieve better retaining effect in the roadway along the goaf, but also reduce the cost and labor. Keywords: Gob-side entry retaining, compressible pier column, surrounding rock movement, numerical simulation, pressure monitoring.