近距离煤层群综采工作面瓦斯治理优选措施

相对于单一煤层或其他煤层群开采,近距离煤层群在开采过程中邻近层受到开采层应力影响更为剧烈,瓦斯更容易通过发育的裂隙涌入开采层,造成开采层工作面瓦斯积聚。现有的针对近距离煤层群的瓦斯治理研究主要侧重于单一措施参数的确定及效果分析,没有深入研究瓦斯治理措施在时间、空间层面之间的联系,对综合瓦斯治理措施的优选组合、具体参数的确定依据及措施采取后的效果分析不够深入。针对上述问题,以阳煤一矿81403综采工作面为研究对象,通过数值模拟方式分析了近距离煤层群条件下开采应力分布及演化过程,研究了上覆岩层破坏及裂隙发育变化规律,得到了81403综采工作面瓦斯主要来源为煤层解吸瓦斯、上邻近层卸压瓦斯、采空区瓦斯等,针对不同瓦斯涌出源头和特点,优先采取顺层预抽+高抽巷+高位钻孔+采空区埋管的瓦斯抽采措施,即在开采前充分预抽减少煤层解析瓦斯量,通过高位钻孔、高抽巷处理邻近层瓦斯涌入,采用埋管治理上隅角瓦斯局部聚集,在时间和空间上形成综合的治理体系,从而达到瓦斯治理目的。实际应用结果表明,工作面回采期间瓦斯抽采率达到了89.9%,回风巷及上隅角瓦斯体积分数保持在1%以下,保证了工作面的安全回采。

Optimal measures for gas control on fully mechanized working face of close-distance coal seam group

Compared with single coal seam or other coal seam group,the mining process of the close-distance coal seam group is more likely to be affected by the stress of the adjacent seam.Moreover,the gas is more likely to gush into the coal seam through the developed fissures,causing gas accumulation on the working face of the mining seam.The existing gas control research for close-distance coal seam group mainly focuses on the determination of single measure parameters and effect analysis,without in-depth research of the relationship between gas management measures in time and space.The researches on the optimal combination of comprehensive gas management measures,the basis for determining specific parameters and the effect analysis after the measures being taken are not sufficient enough.In order to solve the above problems,taking the 81403 fully mechanized working face of No.1 Coal Mine of Yangquan Coal Industry(Group)Co.,Ltd.as the research object,the paper analyzes the stress distribution and evolution process of mining under the conditions of close-distance coal seam group through numerical simulation.The research studies the overlying rock destruction and fissures development change law,and proposes that the main sources of gas on the 81403 fully mechanized working face are coal seam desorption gas,pressure relief gas in upper adjacent coal seam and goaf gas,etc.Based on the different gas emission sources and characteristics,the paper proposes the gas extraction measures of bedding pre-extraction+high extraction roadway+high borehole+buried pipes in the extraction area.Before mining,pre-extraction is applied to reduce the amount of coal seam desorption gas.High extraction roadway and high borehole are used to deal with gas gush from adjacent coal seam.Buried pipes are used to control local gas accumulation in the upper corner.The measures form a comprehensive management system in time and space so as to achieve the purpose of gas control.Practical application results show that the gas extraction rate reaches 89.9%on the working face,and the gas volume fraction of the return airway and upper corner is kept below 1%,ensuring the safe mining of the working face.