Destruction mechanism and control technology of peripheral rock of shallowly buried large mining height roadway under concentrated coal pillar

Abstract

To study the damage mechanism of the return roadway of shallow burial depth, thin bedrock, and large mining height working face under the action of concentrated coal pillar. In this paper, we take the 22408 return roadway of Bulianta Mine as the research background and focus on the problem that the mine pressure appears drastically when it passes over the overlying concentrated coal pillar. Through theoretical analysis and numerical simulation, the mine pressure manifestation law of 22408 working face back to the mining roadway is studied. We analyzed the reasons that led to the drastic manifestation of mine pressure in the 22408 return roadway over the overlying concentrated coal pillar, revealed the damage mechanism of the roadway under this condition, and put forward a reasonable and effective method of controlling the stability of the surrounding rock for this problem. (1) Propose to utilize hydraulic fracturing to control the problem in advance, and set up a drilling field in the 22407 return tunnel to fracture the medium-grained sandstone 20m above the 2–2 coal in advance; (2) Strengthen the support of the area affected by the coal pillar in advance, and replenish three Φ21.6×8150 mm anchor cables with the spacing of 1200 mm-1500 mm-1500 mm-1200 mm on the roof of the tunnel; (3) Strengthen the support of the area affected by the coal pillar in advance; (4) Strengthen the support of the area affected by the coal pillar in advance, and strengthen the support of the area affected by the coal pillar in advance. At this time, three Φ21.6×5150 mm anchor cables with PVC belts were installed on the side gang of the return tunnel, and the optimized return tunnel was monitored on site, and the effect was good.