Research On Arrangement Of Fully-Mechanized Caving Face's Top Tunnel Outside Bottom Return Air Laneway And Stability Of Surrounding Rock

Gas disaster has become a major hazards in coal mine's safety production, especially thick and extremely thick coal seam. While work face lengths, mining height sends up, production increases speedily and gas accumulates full of upside corner, it will inevitably result in ventilation and gas management difficultily, which seriously restricts the safe production and production schedule of mining face. How to disign well the air volume and to selecte a more suitable gas roadway layout system, which is one of the most effective way to solve gas and coal dust accumulation.This paper proposes a new working face ventilation system: top gas tunnel small pillar outside the bottom return air laneway layout, in other words, which is gas tunnel location evolution. It is a fundamental solution to gas and dust accumulation full of the work surface caving section and upper corner of mined area, which provide a safe, efficient ventilation system, achieve small coal pillar arrangement in the top-coal caving, create a good mechanical environment to improve the recovery rate of coal and increased the recovery of the end coal of work face. Meanwhile, the top tunnel existing, can effectively absorb the coal's deformation produced in a large number of high-stress, release of elastic energy accumulated in the coal , promote effectively the stress caused by mining to distribute again, improve the high-stress environment in pillars, and make the tunnel protected in the region of low stress.The orthogonal experimental program obtained related laws of coal thickness, buride depth, coal strength and roof strength how to influence the stability of surrounding rock, arrange the inportant role in order and determine reasonable size of small pillar, based on the top tunnel outside bottom return air laneway arrangement.On these basis, by comprehensively using engineering analogy based on the classification of surrounding rock stability of roadway, design method of expert system, 3-dimention numerical simulation based on the geomechanics condition, the paper summed up reasonable tunnel support scheme while using top tunnel outside bottom return air laneway layout. Finally, these conclusions are applied successfully in thick and extra-thick seam and achieve the desired results.