关键词: 特厚煤层, 小煤柱, 沿空掘巷, 围岩控制, 支卸协同, 双层连续承载结构

Abstract: Gob-side entry driving with small coal pillar is an important way to realize high recovery mining in extra thick coal seam. But large space and high strength mining of extremely thick coal seam leads to high intensity mine pressure behavior, meanwhile, the gob-side roadway is in plastic zone of whole coal. So it is difficult to control surrounding rock. In order to solve the supporting Problem of gob-side roadway in large scale plastic zone of whole coal using anchor-net –cable, taking 8204-2 Small Coal Pillar working face of Tashan coal mine as engineering background. This paper revealed the supporting mechanism of bolt and anchor cable for large-scale plastic zone of gob-side roadway: Bolt support acts on shallow secondary crushing area of surrounding rock, forming shallow continuous load-bearing structure; anchor cable acts on the stable surrounding rock in deep three-way stress state to form a larger range of continuous stable bearing structure. Based on this, the calculation method of effective length of bolt and anchor cable is further clarified. And the synergetic control technology of surrounding rock for gob-side entry driving in extremely thick coal seam was formed, which based on the support of anchor-mesh-cable with high pre-tightening force and high strength, and using abrasive water jet cutting roof pressure relief in hard roof, large diameter borehole pressure relief in roadway side, bottom plate pressure relief groove pressure relief as auxiliary. The engineering application results show that, the maximum deformation of surrounding rock of test roadway is less than 700 mm, which can meet the use requirements.