Width Optimization of Narrow Coal Pillar of Gob-side Entry Driving in Isolated Fully Mechanized Caving Face

In order to solve problems of the severe strata pressure characteristics of the gob-side entry driving and the difficulty in controlling roadway surrounding rock in the isolated fully mechanized caving face, the surrounding rock stability of roadway at isolated fully mechanized caving face under the condition of different width coal pillars was studied based on the theory analysis, numerical simulation and practice method. Based on the abutment pressure distribution regularities combined with the structural mechanical model of roadway driving along goaf, calculating and analyzing respectively from internal stress field and limit equilibrium theory, it is determined that the reasonable width of narrow coal pillar is between 4.46 m and 7.3 m. Using numerical simulation method, the size of narrow coal pillar is compared and analyzed, and the optimal size of narrow coal pillar is 5 m. Field monitoring indicated that the maximum deformation amount of the two sides of the roadway in the working face of 3204 is 147 mm, and the maximum deformation amount of the top and bottom is 95 mm, which can meet the requirements of safety production.