Reasonable Width of Narrow Coal Pillar of Gob-side Entry Driving in Large Mining Height

To determine the reasonable width of the gob-side entry driving coal pillar in Xieqiao Mine, firstly, the theoretical analysis method was applied to construct the mechanical model for limit equilibrium area of coal seam edge, and the distance obtained via analysis between the bearing pressure extremum and the coal edge was 3.34 m. Secondly, the numerical simulation method was applied to analyze the roadway rock mechanics with different coal pillar widths, and it is concluded that the width of the coal pillar was staying in a chaos area which was not conducive to the stability of the system when the peak stress position of the roof changed suddenly and the reasonable width was determined at 5 m. Finally, the high-strength, high pre-stressed bolt and cable anchor supporting test was carried out in the roadway, with 60 mm of roof subsidence, 207 mm of two sides displacement, 305 mm of floor heave, 135 mm of lateral displacement of coal pillar, 7 d duration of strong roadway rock deformation in pressure, in which the deformation meet the safety production of mine and increased the technical and economic benefit remarkably.